Mosses: Not as Simple as You Think (Taxon of the Week: Ectropothecium)

Ectropothecium sandwichense, a moss species with a scattered, mostly tropical distribution on islands in the South Pacific. Photo from here.

I have to admit to becoming increasingly glad that I don't work on mosses. The new Taxon of the Week is a moss, and looking up stuff on it has driven me into a strange world of unfamiliar terminology and fine-scale features. If I mess anything up here, I only hope that the legions of moss fans out there* forgive my transgressions.

*Do not doubt that they're out there. As I've commented before, bryologists are a dedicated bunch.

Ectropothecium is a genus of mostly hydrophytic mosses found worldwide (hydrophytic plants grow either in water or in completely waterlogged soil; some Ectropothecium species do the former, others the latter). It belongs to a clade of mosses known as the pleurocarpous mosses; while other (acrocarpous) mosses branch only rarely and produce terminal archegonia (the female reproductive organs - see the diagram at the posts linked to above) at the end of the stem, pleurocarpous mosses produce lateral archegonia on highly branched and extensively interwoven stems (Shaw & Renzaglia, 2004). Pleurocarpous mosses are divided molecularly into three orders, Ptychomniales, Hookeriales and Hypnales; Ectropothecium belongs to the Hypnales which have a smooth spore capsule with a calyptra (protective cap) that usually opens by splitting along one side (Buck et al., 2004). Within the Hypnales, Ectropothecium is placed in the family Hypnaceae; however, phylogenetic studies of Hypnales (e.g. De Luna et al., 2000) suggest that members of the Hypnaceae may be para- or polyphyletically placed within the order.


Ectropothecium zollingeri, a species with a distribution centred in south-east Asia. Photo from here.

Ectropothecium itself is distinguished by having spore capsules that are very small (usually less than 1 mm long) and almost spherical (Buck & Tan, 2008), non-decurrent leaves (not extending down the stem where they join), short and broad leaf cells and filamentous pseudoparaphyllia that are two or three cells wide at the base (Ireland, 1992). Pseudoparaphyllia are small outgrowths of the stem that cluster around the base of new side-branches (as opposed to paraphyllia which are normally scattered more evenly along the entire stem); they may be thread- or blade-shaped. See Ignatov & Hedenäs (2007) for a review of the distinctions between paraphyllia, pseudoparaphyllia and proximal branch leaves, though to be honest if you understand the difference you're somewhat ahead of me (as far as I can tell, pseudoparaphyllia grow on the stem around the primordium of a new branch and remain on the stem, while proximal branch leaves may start growing around the primordium but end up being transferred to the new branch).

REFERENCES

Buck, W. R., C. J. Cox, A. J. Shaw & B. Goffinet. 2004. Ordinal relationships of pleurocarpous mosses, with special emphasis on the Hookeriales. Systematics and Biodiversity 2 (2): 121-145.

Buck, W. R., & B. C. Tan. 2008. A review of Elmeriobryum (Hypnaceae). Telopea 12 (2): 251-256.

De Luna, E., W. R. Buck, H. Akiyama, T. Arikawa, H. Tsubota, D. González, A. E. Newton & A. J. Shaw. 2000. Ordinal phylogeny within the hypnobryalean pleurocarpous mosses inferred from cladistic analyses of three chloroplast DNA sequence data sets: trnL-F, rps4, and rbcL. Bryologist 103 (2): 242-256.

Ignatov, M. S., & L. Hedenäs. 2007. Homologies of stem structures in pleurocarpous mosses, especially of pseudoparaphyllia and similar structures. In Pleurocarpous Mosses: systematics and evolution (A. E. Newton & R. Tangney, eds) pp. 227-245. The Systematics Association Special Volume Series 71. Taylor& Francis / CRC Press: Boca Raton.

Ireland, R. R. 1992. Studies of the genus Plagiothecium in Australasia. Bryologist 95 (2): 221-224.

Shaw, J., & K. Renzaglia. 2004. Phylogeny and diversification of bryophytes. American Journal of Botany 91 (10): 1557-1581.

Possibly The Coolest Thing I Had Published This Year

Dorsal view of male Australiscutum hunti (missing a few legs, I'll admit). Photo by yours truly.

In 1991, Hunt and Cokendolpher published a paper describing the new harvestman subfamily Ballarrinae and comparing to a selection of long-legged harvestmen from around the globe. In that paper, they referred to an undescribed species of the subfamily Monoscutinae from eastern Australia. For whatever reason, Glenn Hunt never completed a description of this new species before his death but I am happy to say that it has finally been brought into print by Taylor (2009) with the description of three species of the new genus Australiscutum.

Except for the minor detail that Australiscutum is not actually a monoscutine. Monoscutines are small harvestmen from New Zealand; despite belonging to the Phalangioidea, which are known as long-legged harvestmen, monoscutines have relatively short, robust legs. They also have the entire dorsal surface sclerotised (hence the name 'monoscutine' or 'single shield'; in most other phalangioids, only the prosoma or cephalothorax is sclerotised) and ornamented with small nodules. Australiscutum resembles monoscutines in having relatively short legs and while the dorsal surface of the opisthosoma (or abdomen) is not sclerotised, it is covered in small spine-like setae. However, in other features such as genital morphology Australiscutum is quite distinct from monoscutines. Shorter legs and hardened bodies have evolved in a number of different harvestman lineages, such as troguloids and various groups of Laniatores, and are probably an adaptation to a soil-dwelling lifestyle. Though it hadn't been run at the time I submitted this paper, my phylogenetic analysis of Monoscutidae (for which I'll probably be submitting the manuscript in a few days' time) corroborates the lack of a connection between Australiscutum and monoscutines and that the short-legged morphology has arisen twice within the family.

Neat as that is, though, that's not the really cool thing about Australiscutum. This is:



These are the chelicerae (the pincers) of males of the three species of Australiscutum as seen from the front and to roughly the same scale. Except for the appearance of the chelicerae, the differences between each of the species are relatively minor (though A. hunti is the most distinct of the three). Australiscutum hunti has large swollen chelicerae; A. graciliforceps has much smaller slender chelicerae. But when we reach A. triplodaemon, we see that it has one larger, more swollen chelicera and one smaller, more slender chelicera*. This cheliceral asymmetry is unique among monoscutids and, so far as I've been able to find, is unique among harvestmen. In fact, I haven't yet found any previous record of asymmetrical pincers like these for any arachnid.

*The species name of Australiscutum triplodaemon is a reference to the Triple Demons of Compromise in Norton Juster's The Phantom Tollbooth. Of these three, one demon was very tall and thin, the second was very short and fat, and the third one looked exactly like the other two.

So far, I can only make a few vague inferences about why A. triplodaemon has these uneven chelicerae, based on comparisons with asymmetrical pincers in crustaceans (where they are known in a number of different lineages). One thing I can say for sure that it is a true morphological feature and not a pathology. If a crustacean such as a crab or lobster looses a pincer while growing, the new claw that grows back may be smaller, but A. triplodaemon can be inferred to have naturally asymmetrical pincers because (a) it's always the left chelicera that is smaller, and (b) of the other two species in the genus, the one that is closest in appearance to A. triplodaemon (and hence the one that would represent its non-pathological form if it was a developmental accident) is the small-pincered A. graciliforceps and not the large-pincered A. hunti. Many crustaceans develop differently-sized pincers as an adaptation for handling food (for instance, they may use one pincer to hold a prey mollusc and they other to break open its shell) but, again, this seems unlikely to apply to A. triplodaemon as the asymmetrical chelicerae are only found in males. Female Australiscutum have small discrete chelicerae like other monoscutids; unless the females were eating a different diet from the males (not impossible, but unusual), we might expect both sexes to have asymmetrical chelicerae if they were related to food-processing.

The third role that has been recorded for asymmetrical pincers among crustaceans is as part of mating displays (fiddler crabs are the most famous example) and their presence in males only suggests that this is also they role they play for A. triplodaemon*. Determining just how A. triplodaemon uses its odd-shaped pincers will require observation of living specimens.

*Though I say that in the full knowledge that I am largely invoking the old line that "if you don't know what it's for, then it's for display".

I'd like to share one more interesting thing that came out of the review process for this paper. The two most similar species of Australiscutum, A. triplodaemon and A. graciliforceps, are in fact identical except for their chelicerae. Their recorded ranges also overlap, and the possibility occured to me when I was first describing them that they might be different male forms of a single species. Male dimorphism has been recognised in a number of harvestman species, including monoscutids, but because the mode of dimorphism in Australiscutum would differ from modes described previously I decided that the safest approach for now was to treat the two forms as separate species. I hemmed and hawed as to whether I should point out the possibility of their being dimorphs of a single species in the manuscript but eventually decided that it was perhaps too much speculation on my part and left it out (I tend to be fairly cautious in drawing inferrences; I've never been able to decide whether this is a good or bad thing). However, when I received the reviewers' comments, two of the three reviewers had thought of the same possibility without any prompting from me and suggested that I comment on it. So it's there.

REFERENCE

Taylor, C. 2009. Australiscutum, a new genus of Monoscutidae (Arachnida: Opiliones) from eastern Australia, with the first record of asymmetrical chelicerae in Opiliones. Insect Systematics and Evolution 40 (4): 319-332.

Insectivores: Possibility of Puggles (Taxon of the Week: Australosphenida)

A baby echidna or puggle. Normally, the puggle would be contained in a pouch on its mother's underside. Photo from here.

The Australosphenida is a group of mammals that has been studied fairly extensively in recent years, which is not bad going when one considers that, at most, less than twenty species have been assigned to it and some authors are of the opinion that the majority of those should not be regarded as australosphenidans at all.

The undoubted Australosphenida (or, more correctly if dealing with the restricted grouping, Ausktribosphenida) are five small Mesozoic insectivores (Rougier et al., 2007) - Asfaltomylos patagonicus and Henosferus molus from Jurassic South America, Ambondro mahabo from Jurassic Madagascar, and Ausktribosphenos nyktos and Bishops whitmorei from Cretaceous Australia. Despite their probably being fairly unprepossesing animals in life (as far as we can tell - so far, ausktribosphenids are only known from teeth and jaw bones), ausktribosphenids have provoked a fair amount of interest because of the resemblance between their teeth and those of modern marsupials and placentals. All three groups possess an arrangement called the tribosphenic molar, in which the lower molars each have a large posterior depression that contacts with a large cusp in the corresponding position on an upper molar, facilitating the grinding of food ("like a mortar and pestle", is the comparison that has been used in print).


Evolution of the tribosphenic molar as presented in Luo et al. (2001). Steropodon is an early monotreme; Northern Hemisphere tribosphenids are the clade marked "Boreosphenidans".

The discovery of tribosphenid mammals in Gondwana earlier than they had been found in northern continents (where they appear in the early Cretaceous) therefore led to the suggestion that tribosphenid mammals may have evolved in the Southern Hemisphere and only later spread to the North (modern marsupials, despite their current Southern Hemisphere distribution, were derived from Northern Hemisphere Mesozoic ancestors). However, further phylogenetic analyses lead to the alternative suggestion (Luo et al., 2001) that ausktribosphenids evolved the tribosphenic molar independently from Northern Hemisphere tribosphenids. Instead, Luo et al. (2001) placed ausktribosphenids as related to modern monotremes, which lack tribosphenid molars but share with ausktribosphenids a distinct shelf (the cingulum) around the front of the molars. This ausktribosphenid + monotreme grouping is what Luo et al. (2001) dubbed the Australosphenida. Later analyses (e.g. Rougier et al., 2007) make the 'ausktribosphenids' paraphyletic with regard to monotremes. Alternatively, some analyses have continued to support a monophyletic tribosphenid clade uniting ausktribosphenids, marsupials and placentals that excludes monotremes (Rowe et al., 2008). Things are not made easier by the point that, while ausktribosphenids are known from little else than teeth, known monotremes, both living and fossil, mostly have teeth that are vestigial, absent or just plain wierd (Kollikodon, I'm looking at you).


Kollikodon ritchiei. This Cretaceous monotreme had strangely rounded molars (it has been informally referred to as "Hotcrossbunodon") that may have been used for crushing molluscs. Or they may have been used for something else entirely.

Living monotremes are, of course, restricted to Australia, though it wasn't always so - Monotrematum sudamericum is a monotreme known from the Palaeocene of South America. Other known fossil genera are all Australian. I won't bore you with the things everybody already knows about monotremes - the presence of venomous ankle spurs in platypuses, the four-headed penis of echidnas, or the fact that baby echidnas (which are held in a pouch on the mother's underside) are known as puggles. Some things I will mention - if you've never seen a live echidna, they're a lot bigger than you think they are (I don't know how big you think they are, but I can assure you that they're bigger). According to Wikipedia, Tachyglossus aculeatus, the short-beaked echidna (the species found in mainland Australia), reaches about a foot and a half in length, while the New Guinean Zaglossus species are even bigger. The extinct mainland Australian species known as 'Zaglossus' hacketti (probably not a Zaglossus, but unrevised) would have been as large as a sheep. Echidnas when disturbed are able to dig with their fore-feet in such a way that they effectively sink into the ground while remaining horizontal, meaning that they retain full protection from their spines. In some areas (best known on Kangaroo Island in South Australia; see here) echidnas may form trains - shortly before a female becomes sexually receptive, a train of up to ten males will begin to follow her around in single file, waiting for her to give them the go-ahead*. Echidnas mate lying on their sides dug into a trench made by the male.

*If humans were to do this, it would be regarded as creepy. Echidnas don't seem to have this problem.

And in case you were wondering, I have been informed that the best way to deal with the spines when cooking an echidna is to roast it whole with the spines still on; after it's finished cooking, the spines can be pulled out fairly easily.

REFERENCES

Luo, Z.-X., R. L. Cifelli & Z. Kielan-Jaworowska. 2001. Dual origin of tribosphenic mammals. Nature 409: 53-57.

Rougier, G. W., A. G. Martinelli, A. M. Forasiepi & M. J. Novacek. 2007. New Jurassic mammals from Patagonia, Argentina: a reappraisal of australosphenidan morphology and interrelationships. American Museum Novitates 3566: 1-54.

Rowe, T., T. H. Rich, P. Vickers-Rich, M. Springer & M. O. Woodburne. 2008. The oldest platypus and its bearing on divergence timing of the platypus and echidna clades. Proceedings of the National Academy of Sciences of the USA 105 (4): 1238-1242.

Name the Bug #8: Prosobonia cancellata

Prosobonia cancellata - photo by Ron Hoff.

Prosobonia cancellata, the Tuamotu sandpiper, is a small to medium-sized bird found on a small number of coral atolls in French Polynesia. It is currently endangered with probably about 1200-1300 surviving individuals in 2003, mostly on the two islands of Tenararo and Morane (Pierce & Blanvillain, 2004). Zusi & Jehl (1970) included Prosobonia in the subfamily Tringinae, which also includes the Tringa sandpipers, Numenius (curlews) and Limosa (godwits). Prosobonia differs from these genera in living higher up on the shoreline, including the atoll forest, feeding on small invertebrates gleaned among leaf litter and off trees. They also seem to eat a reasonable amount of plant material such as seeds.

Other Prosobonia species were once found on a number of tropical Polynesian islands, while P. cancellata itself was previously more widespread with a range extending to Kiritimati (Christmas Island) in Kiribati. Some authors have regarded the Tuamotu and Kiritimati populations as separate subspecies or species, but Zusi and Jehl (1970) pointed out that the only known specimen from Kiritimati (unfortunately no longer available) probably lay within the known range of variation for Tuamotu specimens. Prosobonia leucoptera was found on Tahiti and Moorea (again, some authors have regarded the two populations as separate species) while undescribed subfossils have been found on Henderson, Marquesas and Cook Islands. Prosobonia cancellata has also been placed in a separate genus, Aechmorhynchus, from P. leucoptera, but again Zusi & Jehl established that significant differences between the two species were few except for coloration pattern (P. cancellata has barred plumage, while P. leucoptera was plainer) so there can be little doubt of their close relationship relative to other taxa.

REFERENCES

Pierce, R. J., & C. Blanvillain. 2004. Current status of the endangered Tuamotu sandpiper or titi Prosobonia cancellata and recommended actions for its recovery. Wader Study Group Bulletin 105: 93-100.

Zusi, R. L., & J. R. Jehl Jr. 1970. The systematic relationships of Aechmorhynchus, Prosobonia, and Phegornis (Charadriiformes; Charadrii). Auk 87: 760-780.

Name the Bug #8

Attribution, as always, to follow.

Update: Identity now available here. Photo by Ron Hoff.

Name the Bug # 7 - Apalopteron familiare hahasima

Apalopteron familiare hahasima - photo by Outsuka Hiroyuki.

Apalopteron familiare, the Bonin honeyeater, is a small bird of the Japanese Ogasawara (or Bonin) island group in the north-west Pacific. Phylogenetically speaking, it's been shuffled around a bit over the years - originally described as a species of bulbul, it seems to have been regarded by many authors as some sort of timaliid (babbler) until Deignan identified it in 1958 as belonging to the Meliphagidae (honeyeaters), mainly on the basis of its branched, brushed tongue. There it stayed until molecular analysis re-identified it as a member of the white-eyes (Driskell & Christidis, 2004). There are two funny things about this - (1) Apalopteron really does look like a white-eye (albeit a large one), so identifying it as one is hardly surprising; (2) further phylogenetic analysis has also placed the white-eyes (previously regarded as a separate family) within the Timaliidae (Gelang et al., 2009), making Apalopteron's older position correct after all.

The Ogasawara islands are arranged in three groups - from north to south, these are the Mukojima, Chichijima and Hahajima groups. Shima (which often becomes voiced to -jima when used in a compound) is Japanese for "island", while chichi is "father" and haha is "mother" (other islands in the group include ani and otōto [elder and younger brother] and ane and imōto [elder and younger sister]). Apalopteron familiare was originally found on all three groups, but currently survives only in the Hahajima group. As on many Pacific islands, the Ogasawara fauna has been pretty heavily hit since the arrival of humans due to habitat disturbal and introduced predators - among the endemic species to have become extinct in the group are a heron (Nycticorax crassirostris), pigeon (Columba versicolor), thrush (Turdus terrestris), finch (Chaunoproctus ferrugineus) and bat (Pipistrellus sturdeei) (Iwahashi, 1992). The type subspecies of Bonin honeyeater (Apalopteron familiare familiare) became extinct on Mukojima by the 1940s (Morioka & Sakane, 1978)*. Kawakami et al. (2008) found that dispersal between populations of Apalopteron on separate islands was very low, which would further increase its vulnerability.

*It is possible that a bit of revision may be required here. Suzuki & Morioka (2005) indicated that the type locality for Apalopteron familiare was probably Chichijima rather than Mukojima. Chichijima is considerably closer to Hahajima than it is to Mukojima, raising the question of whether the correct subspecies has been identified as the type.

REFERENCES

Driskell, A. C., & L. Christidis. 2004. Phylogeny and evolution of the Australo-Papuan honeyeaters (Passeriformes, Meliphagidae). Molecular Phylogenetics and Evolution 31 (3): 943-960.

Gelang, M., A. Cibois, E. Pasquet, U. Olsson, P. Alström & P. G. P. Ericson. 2009. Phylogeny of babblers (Aves, Passeriformes): major lineages, family limits and classification. Zoologica Scripta 38: 225-236.

Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.

Kawakami, K., S. Harada, T. Suzuki & H. Higuchi. 2008. Genetic and morphological differences among populations of the Bonin Islands white-eye in Japan. Zoological Science 25 (9): 882-887.

Morioka, H., & T. Sakane. 1978. Observations on the ecology and behavior of Apalopteron familiare (Aves, Meliphagidae). Memoirs of the National Science Museum, Tokyo 11: 169-188, pl. 7-8.

Suzuki, T., & H. Morioka. 2005. Distribution and extinction of the Ogasawara Islands honeyeater Apalopteron familiare on Chichijima, Ogasawara Islands. Journal of the Yamashina Institute for Ornithology 37 (1): 45-49.

Conodonts: They Just Got Scarier

Reconstructed apparatus of Besselodus arcticus, from Dzik (1991).

I've told you before about conodonts, Palaeozoic microcarnivores with impressive tooth arrays. In the earlier post, I referred mostly to ozarkodinids, later conodonts that had grasping teeth in the front of their mouths and crushing plates towards the back. In this post, I'll be referring to panderodontids, an earlier group that lacked the crushing plates of ozarkodinids and had a tooth apparatus made up of simpler fang-like elements, similar to the reconstruction above. Apparatus of panderodontids have been found preserved in association, but we don't yet have preserved examples as good as available for the ozarkodinids.



With such different apparatus, panderodontids were obviously capturing and processing prey differently to ozarkodinids, and a paper just out by Szaniawski (2009) suggests one of those differences. Panderodontids and many other conodonts with coniform teeth had long grooves on the inner surface of some of their teeth (as seen in the photo of a Dapsilodus mutatus element above from Szaniawski, 2009) and Szaniawski points out that these grooves are extremely similar to those seen in the fangs of many venomous fish, lizards and snakes. He therefore infers that panderodontids were similarly venomous. As well as making conodont apparatus even more impressive than they already were, this would make panderodontids the earliest known venomous chordates*.

*Szaniawski refers to them as the "oldest known venomous animals". However, cnidarians had already been around for some time, and while the cnidarian venom delivery system doesn't fossilise, the fact that these were crown-group cnidarians makes it a pretty sure bet that they had it by then.

Earlier suggestions that the groove provided an anchoring point for muscles were couched in the belief that conodont elements were permanently internal, a view that is no longer standard*. Other forms of conodont lacked the venom groove, further evidence of the conodonts' ecological diversity.

*Conodont elements grew as new layers were put down over the outer surface, which is admittedly a little difficult to reconcile with their current interpretation as grasping teeth (which would require the absence of tissue cover). It seems likely that conodont teeth were only exposed when being actively used; at other times they would have been retracted into a covering pocket, in the same manner as the grasping spines of modern chaetognaths.

REFERENCES

Dzik, J. 1991. Evolution of oral apparatuses in the conodont chordates. Acta Palaeontologica Polonica 36 (3): 265-323.

Szaniawski, H. 2009. The earliest known venomous animals recognized among conodonts. Acta Palaeontologica Polonica 54 (4): 669-676.

Re-opening the Door (Taxon of the Week: Clausilioidea)

The latest Name the Bug challenge has been successfully identified as Apalopteron familiare, the Bonin honeyeater. I'll put up a descriptive post for that species in the next few days, but for now it's Taxon of the Week time.


A fantastic shot of the clausiliid Cochlodina laminata by Dietrich Meyer. The shell of this individual was 17 mm long.

The new Taxon of the Week is a repeat performance - Clausilioidea or door snails were featured here earlier this year and I'd recommend reading that post before this one. As mentioned there, one of the characteristic features of Clausiliidae (the family including all living clausilioids) is that they have very narrow, tall shells. Cain (1977) found that the distribution of shell shapes among terrestrial snails tended to be bimodal - shells were usually very long and thin or short and flatter, with very few being only slightly elongate. At least one factor in this difference in shell shapes appears to be choice of feeding territory* - elongate snails prefer grazing on very steep or vertical surfaces while shorter snails prefer more horizontal surfaces (Goodfriend, 1986). Studies on the behaviour of the clausiliid Cristataria genezarethana by Heller & Dolev (1994) found that they spent most of their lives sheltering in crevices - an individual snail would only be active for about six to twelve days of the year. Growth was estimated to be correspondingly slow - it may take eleven years for a Cristataria to reach maturity.

*In discussing possible reasons for the bimodality of shell shapes, Cain (1977) provided a very pithy summary of the problem in studying snail behaviour - "It is of course true that most species of snail when active are nocturnal or at least crepuscular, while conchologists are largely diurnal".


Congregation of aestivating individuals of the clausiliid snail Albinaria caerulea. This is one of the more widespread species of Albinaria, found in coastal western Turkey and the Cyclades islands of Greece, while an isolated population in Attica in Greece may have resulted from human transportation. Photo by Aydin Örstan.

Perhaps the most extensively studied clausiliid group is the Mediterranean genus Albinaria, found in southern Greece and Turkey. Albinaria shows a high level of apparent diversity - over 200 species and subspecies have been described. Many of these taxa occupy highly restricted distributions, and sympatry within the genus is rare. However, narrow hybrid zones exist between many "species", and they can often be interbred readily in the laboratory (Douris et al., 1998), leading to the suggestion that the number of true species involved may be much lower and that many supposed "species" may instead represent ecotypes. Comparable patterns of diversity are known from other land snail genera; one of the most notorious examples is the West Indian genus Cerion, the taxonomy of which was an early research topic of Stephen Jay Gould and a strong influence in the development of his opinions on developmental constraints and evolutionary contingencies. Molecular studies of Albinaria have supported the recognition of certain species, but failed to distinguish between others (Giokas, 2000). In some cases, two morphologically distinct "species" might form a clade together but remain intermixed within the clade, suggesting that they are indeed ecological variants of a single species.

REFERENCES

Cain, A. J. 1977. Variation in the spire index of some coiled gastropod shells, and its evolutionary significance. Philosophical Transactions of the Royal Society of London Series B - Biological Sciences 277 (956): 377-428.

Douris, V., R. A. D. Cameron, G. C. Rodakis & R. Lecanidou. 1998. Mitochondrial phylogeography of the land snail Albinaria in Crete: long-term geological and short-term vicariance effects. Evolution 52 (1): 116-125.

Giokas, S. 2000. Congruence and conflict in Albinaria (Gastropoda, Clausiliidae). A review of morphological and molecular phylogenetic approaches. Belg. J. Zool. 130 (Suppl. 1): 93-100.

Goodfriend, G. A. 1986. Variation in land-snail shell form and size and its causes: a review. Systematic Zoology 35 (2): 204-223.

Heller, J., & A. Dolev. 1994. Biology and population dynamics of a crevice-dwelling landsnail, Cristataria genezarethana (Clausiliidae). Journal of Molluscan Studies 60 (1): 33-46.

Hints for Name the Bug # 7

Yesterday's Name the Bug challenge is still sitting there without a successful identification, so here's some hints:

1. Phylogenetic wanderer, perhaps not so fond of honey after all.

2. Mama's still got it; Papa's lost it.

Name the Bug #7

After the last entry was obviously so difficult, I've decided to go a little easier on you all this time:



Attribution, as always, to follow.

Update: Identity now available here. Photo by Outsuka Hiroyuki.

Voice of the Iron Lady

Margaret Thatcher, bane of an entire generation of British liberals*, recently (Correction: not that recently, but in 1990) spoke at the 2nd World Climate Conference, and you can read a transcript of her speech online. Climate change isn't something I mention often at this site - it's really not my field of expertise. But I thought that I would like to share one excerpt with you:

Many of the precautionary actions that we need to take would be sensible in any event. It is sensible to improve energy efficiency and use energy prudently; it's sensible to develop alternative and sustainable and sensible ... it's sensible to improve energy efficiency and to develop alternative and sustainable sources of supply; it's sensible to replant the forests which we consume; it's sensible to re-examine industrial processes; it's sensible to tackle the problem of waste. I understand that the latest vogue is to call them ‘no regrets’ policies. Certainly we should have none in putting them into effect.

The thing that has always confused me about the climate change 'debate' is that I don't really see why there needs to be a debate in the first place. Ultimately, the best methods being proposed to combat climate change seem to come down to reducing pollution, and reducing waste. Irrespective of whether anthropogenic climate change is happening or not, these are good things in themselves. It strikes me as being a bit like the idea that bathing regularly reduces the likelihood that you will get sick. Maybe there's a chance that you won't become ill even if you don't wash yourself for a fortnight - but you would still feel better if you had, nonetheless.

*Does anyone else here remember The Tin-Pot Foreign General and the Old Iron Woman?

Soft yet Scaly (Taxon of the Week: Coccidae)

The stellate scale Vinsonia stellifera (Coccidae). Scales are insects that have abandoned motility for most of their lives to become sedentary plant suckers. Photo from here.

The truly bizarre insects known as scales have been covered at this site previously, including a brief description of the scale life cycle. In that post I referred to the ensign scales or Ortheziidae; in this post I'll cover the soft scales or Coccidae. The Coccidae include about 1000 species, some of which produce a dorsal covering of wax while others lack a dorsal covering (Williams, 1991). While ortheziids belong to the group of scale families known as archaeococcids, coccids belong to the more derived grouping known as neococcids. Neococcids are distinguished from archaeococcids by the absence of spiracles on the abdomen, and of compound eyes in the adult males (instead, male neococcid eyes have become reduced to dissociated ocelli). Coccids are distinguished from other neococcid families by the presence of a pair of rounded or triangular plates at the base of the anal cleft (Williams, 1991).


While female scales remain immotile for the rest of their lives once they have found a host, males regrow their legs and usually develop wings at maturity to find females. This is the Kuno scale Eulecanium kunoense. Photo by Joyce Gross (and very impressive it is too - photographing something as minute as a male scale would not be an easy call.

Another distinctive feature of neococcids is something referred to as Paternal Genome Loss (PGL - also known as Paternal Genome Elimination). In most neococcid families, males are technically diploid but early in development the chromosomes a male has inherited from its father are all inactivated so that it becomes functionally haploid. When the male produces sperm, these inactivated chromosomes are eliminated from sperm production and only the maternally-inherited chromosomes are passed on to its offspring. The reason for the evolution of PGL remains unknown*, but it appears likely to have evolved among neococcids on a single occasion (Yokogawa & Yahara, 2009). True haplodiploidy as found in Hymenoptera, where males are truly haploid as opposed to functionally haploid, has also evolved in scales of the archaeococcid family Margarodidae but is as yet unknown among neococcids despite suggestions that PGL may be a precursor to the origin of haplodiploidy. It is worth noting that, while an origin of haplodiploidy from PGL may seem reasonably intuitive, there is the small problem that there are more than twice as many known cases of taxa evolving haplodiploidy as PGL.

*Endosymbiotic bacteria such as Wolbachia have been shown to cause PGL in some insects (and the presence or absence of endosymbionts has been shown to affect PGL in at least one neococcid); alternatively, it could result from genetic factors on the animal's own X chromosome promoting the transmission of maternal chromosomes.

REFERENCES

Williams, D. J. 1991. Superfamily Coccoidea. In The Insects of Australia, 2nd ed. vol. I pp. 457-464. Melbourne University Press.

Yokogawa, T., & T. Yahara. 2009. Mitochondrial phylogeny certified PGL (Paternal Genome Loss) is of single origin and haplodiploidy sensu stricto (arrhenotoky) did not evolve from PGL in the scale insects (Hemiptera: Coccoidea). Genes Genet. Syst. 84: 57-66.

Name the Bug: Alaskiella medfraensis

Alaskiella medfraensis (from Frýda & Blodgett, 1998)

No-one successfully identified this one. I guess Palaeozoic gastropods just don't have the same following as other animals.

Alaskiella medfraensis is a member of the Porcellioidea, a superfamily of gastropods containing the Palaeozoic Porcelliidae and the Mesozoic Cirroidea. Porcellioids are distinguishable from other gastropods by virtue of being the only heterostrophic vetigastropods. I'll explain what that means, and I apologise in advance if it's a little hard to follow. I know it confuses the hell out me.

I've previously explained the difference between dextral and sinistral gastropods and how to distinguish the two. The method that I described therein is the correct one for orthostrophic shells. Orthostrophic growth is the standard gastropod growth pattern with the shell growing in a downwards spiral. However, some types of gastropod are hyperstrophic which essentially means that from a developmental perspective they grow upwards rather than downwards. Because the shell's "correct" orientation is therefore rotated 180° from that of an orthostrophic shell, if you hold a hyperstrophic shell with the aperture downwards a dextral shell is going to appear sinistral and vice versa. In life, of course, the aperture will still be held downwards in a hyperstrophic gastropod, but they can still be distinguished because the positions of the organs (gastropods are bilaterally asymmetrical) will be reversed - the stuff that you'd expect to see on the left side will instead be on the right. In the case of fossil gastropods, where you can't look at the organs, distinguishing hyperstrophic shells becomes a lot more difficult and I have to confess that I really don't see how they do it (apparently the shape and orientation of the aperture may offer some indications).

Heterostrophic shells like Alaskiella start off life growing upwards like a hyperstrophic shell but then change the direction of growth to downwards. As a result of this, they also change the direction of spiralling - so Alaskiella starts off spiralling upwards dextrally before it spirals downwards sinistrally. Among living gastropods, heterostrophic coiling is characteristic of the Heterobranchia, the clade that includes opisthobranchs (sea slugs and related animals) and pulmonates (lung-breathing snails). However, porcellioids developed heterostrophy independently of heterobranchs; instead, they belong to the Vetigastropoda, the clade including trochids (top shells) and turbinids (cat's-eye or turban shells). The main characters showing porcellioids to be vetigastropods are the presence of a vetigastropod-type protoconch (the embryonic shell) and nacre (the shiny inner layer of, for instance, a paua shell [Haliotis iris]; Frýda et al., 2008). Neither of these features is really visible in the figure above (nacre has only been identified as preserved in one cirrid genus so far) but you can readily see the large selenizone, the groove running around the outer edge of the whorls, which tends to be a characteristic of vetigastropods*. Porcellioids can also be distinguished from heterobranchs in that while heterobranchs change the direction of coiling at the transition point between the protoconch and the teleoconch (the post-embryonic or post-larval shell), porcellioids change directly during the early part of the teleoconch (Frýda & Blodgett, 2004).

*To be scrupulously correct, not all vetigastropods have a selenizone and not every gastropod with a selenizone (which may be a groove or may be a row of openings) is a vetigastropod. However, in general, non-vetigastropods with selenizones have only small ones.

Alaskiella medfraensis differs from other porcellioids in that other porcellioids have the axis of coiling of the protoconch parallel to that of the teleoconch, but Alaskiella has the axes offset at an angle. The change in the axis of coiling is what gives Alaskiella its characteristic looped look where the shell changes direction, which always puts me in mind of the looped peak that tends to form at the top of a meringue when you spoon it out.

REFERENCES

Frýda, J., & R. B. Blodgett. 1998. Two new cirroidean genera (Vetigastropoda, Archaeogastropoda) from the Emsian (late Early Devonian) of Alaska with notes on the early phylogeny of Cirroidea. Journal of Paleontology 72 (2): 265-273.

Frýda, J., & R. B. Blodgett. 2004. New Emsian (Late Early Devonian) gastropods from Limestone Mountain, Medfra B-4 quadrangle, west-central Alaska (Farewell Terrane), and their paleobiogeographic affinities and evolutionary significance. Journal of Paleontology 78 (1): 111-132.

Frýda, J., R. B. Blodgett, A. C. Lenz & Š. Manda. 2008. New porcellioidean gastropods from Early Devonian of Royal Creek area, Yukon Territory, Canada, with notes on their early phylogeny. Journal of Paleontology 82 (3): 595-603.

Return of the Water Bears (Taxon of the Week: Tardigrada)

False colour SEM image of two tardigrades, from here.

If you're a long-time reader of this site, you're probably already aware of the existence of tardigrades or water bears, microscopic stumpy-legged invertebrates. Previous posts on Tardigrada have given an overview of the main subgroups of tardigrades, and suggested how you might find your own specimens. The next logical step, I suppose, would be to say a few things about tardigrade ecology, and for that I shall draw heavily from the excellent reviews of Nelson & Marley (2000) and Nelson (2002).

Tardigrades may live in salt water, fresh water or terrestrially among mosses and leaf litter. However, because all tardigrades require at least a film of water to live in, the boundary between freshwater and terrestrial species is a trifle blurry and many species can be found in both. Tardigrades feed on plants and algae; their mouthparts have a piercing stylus through which they suck the cytoplasm out of cells. Different techniques are used for collecting marine and limno-terrestrial species, and I mention that solely because it gives me an opportunity to note that one of the methods for collecting marine tardigrades (and other sand-dwelling meiofauna) involves sieving material through a fine mesh net referred to as "Higgins' mermaid bra" (or, depending on author, "Gwen's mermaid bra", as it was Mrs Higgins who invented the tool used by her husband).


Close-up of the head of the tardigrade Macrobiotus. The stylet apparatus is visible inside the head; the stylets are everted when the animal is feeding. Photograph by Martin Mach.

In one of my earlier posts, I referred to the well-known ability of tardigrades to form resistant tuns when exposed to unfavorable conditions, a process called cryptobiosis. What I did not explain at that time was that five different types of cryptobiosis have been identified in tardigrades: encystment (production of a dormant phase without significant water loss), anoxybiosis (resistance to low oxygen levels), cryobiosis (resistance to freezing temperatures), osmobiosis (resistance to elevated salinity) and anhydrobiosis (resistance to desiccation). Not all tardigrades share all five resistances - for instance, anhydrobiosis (the best-known form) is only found among terrestrial tardigrades - and different species will have different degrees of resistance. Much has been made of the resilience of at least some tardigrade tuns, such as their ability to survive immersion for up to eight hours in liquid helium at -272°C (Rebecchi et al., 2007; for comparison, absolute zero is calculated to be -273.15°C) and even to survive exposure to the vacuum of space (Jönsson et al., 2008). However, the often-repeated claim that tardigrade tuns can survive for more than one hundred years seems to be unsupported (Jönsson & Bertolani, 2001, reviewed the 1948 report generally cited in support of this claim and found that the tuns tested in that report in fact failed to revive); tuns have not yet been definitely shown to survive for more than ten years.



Cryobiosis, the ability to withstand freezing, allows tardigrades to inhabit cryoconite holes like the one shown above in a photo from here. Cryoconite holes develop when darkly-coloured dust accumulates in patches on a sheet of ice; the increased heat absorption by the dark dust melts the surrounding ice, forming a small patch of liquid water. This water may then become home to bacteria, algae and other microscopic organisms released by the melting ice - a self-contained microscopic ecosystem where a nematode may be the most fearsome predator in town. The cryoconite hole may freeze up again when the winter comes, of course, but its inhabitants can wait in the ice for the sun to come again.

REFERENCES

Jönsson, K. I., & R. Bertolani. 2001. Facts and fiction about long-term survival in tardigrades. Journal of Zoology 255 (1): 121-123.

Jönsson, K. I., E. Rabbow, R. O. Schill, M. Harms-Ringdahl & P. Rettberg. 2008. Tardigrades survive exposure to space in low Earth orbit. Current Biology 18 (17): R729-R731.

Nelson, D. R. 2002. Current status of the Tardigrada: evolution and ecology. Integrative and Comparative Biology 42 (3): 652-659.

Nelson, D. R., & N. J. Marley. 2000. The biology and ecology of lotic Tardigrada. Freshwater Biology 44 (1): 93-108.

Rebecchi, L., T. Altiero & R. Guidetti. 2007. Anhydrobiosis: the extreme limit of desiccation tolerance. Invertebr. Survival J. 4: 65-81.

Hints for # 6

A quick reminder that no-one has yet made a guess for Name the Bug #6. So a couple of hints:

(1) Devonian

(2) Aydin's comment that the animal is sinistral is incorrect, or at least not entirely correct.

    (2a) Take a close look at the protoconch.

Name the Bug # 6

(Attribution to follow)

It may be a couple of days before I identify this one (assuming that it doesn't follow the usual pattern and have someone successfully identify it within a matter of minutes). I'm not entirely sure of the actual size of the organism shown (why the hell don't invertebrate palaeontologists at least use scale bars?) but I think it's a couple of millimetres long.

Update: The identity of this organism is now available here. Figure from Frýda & Blodgett (1998).

Name the Bug: Anomalurus pelii auzembergeri

Anomalurus pelii auzembergeri (photo from here)

The "scaly-tailed squirrels" of the family Anomaluridae are seven species in three genera of arboreal rodents found in western and central Africa. Like pretty much everything from western and central Africa, they're somewhat enigmatic. Relationships between anomalures and other rodents have long been debated; it seems likely that their closest relative is the springhaas Pedetes capensis, another African endemic (Blanga-Kanfi et al., 2009), but the relationship is not an overly close one, nor can we be really confident where the springhaas-anomalure clade sits in turn. One thing we can be reasonably sure of is that anomalures are not closely related to squirrels (despite the common name).

The names "scaly-tailed squirrel" and "Anomaluridae" (i.e. "strange tail") both refer to the double-row of keeled scales under the base of the tail, visible in the photo above. These scales are used to grip the tree on which the animal is climbing, and also as accessory landing gear in the two gliding genera, Anomalurus and Idiurus (Nowak, 1999). The monotypic third genus, Zenkerella insignis, lacks a gliding membrane (patagium). Idiurus and Zenkerella are currently regarded as more closely related than either is to Anomalurus, but this relationship does not seem to have been formally tested phylogenetically. In the two gliding genera, an elongate cartilaginous process extends from the elbow to support the patagium; similar processes have been evolved by other gliding mammals (Johnson-Murray, 1987), but anomalurids are remarkable in just how much it has been developed.

Anomalurus pelii is the largest of the anomalures, up to two kilograms in weight, and is found from Liberia to the Ivory Coast. The individual in the photo above is the Liberian subspecies A. pelii auzembergeri which differs from other subspecies in lacking bright white patches on the head and along the margins of the patagium, as seen in the photo below from here.



REFERENCES

Blanga-Kanfi, S., H. Miranda, O. Penn, T. Pupko, R. W. DeBry & D. Huchon. 2009. Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades. BMC Evolutionary Biology 9: 71.

Johnson-Murray, J. L. 1987. The comparative myology of the gliding membranes of Acrobates, Petauroides and Petaurus contrasted with the cutaneous myology of Hemibelideus and Pseudocheirus (Marsupialia, Phalangeridae) and with selected gliding Rodentia (Sciuridae and Anomaluridae). Australian Journal of Zoology 35 (2): 101-113.

Nowak, R. M. 1999. Walker's Mammals of the World 6th ed., vol. 1. Johns Hopkins University Press.

Name the Bug #5

(Attribution to follow)

Hint: it's not a bug.

Update: Identity now available here. Photo from here.

A Pathetic Plea for Recognition, and a Platypus-billed Duck

The closing date of submissions for this year's OpenLab, an annual collection of the year's best science-blog writting (as judged by the judges), is the 1st of December - a week from today. If there has been anything here at Catalogue of Organisms over the past year (since December the 1st last year), please (please!) submit it for consideration. Please! Go through the archive in the right sidebar, pick out your favourites, and make your contribution towards restoring my fragile sense of self-worth.

Otherwise, your humble host is still fairly knackered after getting back from the field yesterday (two weeks away = nearly three hundred e-mails [mostly spam], 1000+ entries on Google Reader, one pair crossed eyes). So just a brief finishing note:



This is the braincase of Talpanas lippa, a subfossil duck species, about the size of a mallard, described from Kauai by Iwaniuk et al. (2009) in Zootaxa today (and the article is freely available to all comers). As well as the braincase, Talpanas is also represented by pieces of jaw and leg bones and a partial pelvis. The name means "nearly blind mole-duck" - Talpanas would have had small, piggy little eyes, quite unusual in a bird, and would have almost certainly been nocturnal and flightless (flying blind is not usually recommended). Though the complete beak is still unknown, the available jaw pieces indicate that it would have been very broad. The leg bones indicate that Talpanas was a walker rather than a swimmer, so Talpanas was probably a forager for small invertebrates among forest litter; this is the lifestyle currently pursued by the kiwi, another nocturnal bird with relatively small eyes. Iwaniuk et al. suggest that Talpanas also resembled a platypus in using its broad bill to feel for invertebrates amongst the soil. The opening for the trigeminal nerve in the braincase is very large like that of a platypus (it's the opening labelled 'V' on the images above - take a look, it's freaking huge), indicating that Talpanas' bill would have been very sensitive to touch. Unfortunately, the skull of Talpanas is so unusual that its relationships with other anseriforms are obscure.

Thistle Be The One (Taxon of the Week: Carduoideae)

The cardoon Cynara cardunculus with humans to scale. Photo from here.

The composite-flowering plants of the Asteraceae are one of the largest (23,000 species, according to Wikipedia) and most distinctive plant groups out there - even a complete botanical dunce like yours truly can usually recognise an example of Asteraceae. Asteraceae include such plants as daisies and chrysanthemums in which the "flower" is in fact a large number of tiny flowers all pressed together, hence the old name for the family of "Compositae". Different authors have proposed different classifications within Asteraceae over the years, but twelve subfamilies were recognised by Panero & Funk (2008). The subfamily Carduoideae as recognised by these authors includes the three tribes Dicomeae, Tarchonantheae and Cardueae (earlier authors had used the name to cover a broader paraphyletic assemblage, or restricted it to include only Cardueae). The genus Oldenburgia may be included in Tarchonantheae or it may be placed in its own separate tribe (Funk et al., 2009). No unique morphological features characterise this subfamily (though most species have a ring of papillae on the style underneath the stigmatic branches), but it is well supported molecularly.

The tribes Dicomeae and Tarchonantheae are primarily found in Africa and Madagascar (two species of Dicomeae and one of Tarchonantheae are found in Asia). The seventeen species of Tarchonantheae (including Oldenburgia) are all shrubs or trees; the 75-100 species of Dicomeae include herbs, shrubs and trees. Tarchonantheae includes the genus Brachylaena, species of which predominate in southern African and Madagascan woodlands. Brachylaena species are noted for producing dense, high quality wood, and are also among the largest of the Asteraceae, reaching 40 m in height (Beentje, 2000).


Brachylaena discolor from southeastern Africa. Photo from here.

The largest by far of the three tribes is the Cardueae*, the thistles, with some 2500 species distributed through Eurasia from the Mediterranean to central Asia. The majority of Cardueae are herbs, though there are a few small shrubs or even small trees in the tribe. Most members of Cardueae have distinctive discoid flower heads** and, of course, many have spiny leaves.

*I have just been through the painful, arduous and not-entirely-productive process of trying to decide whether 'Cardueae' or 'Cynareae' is the correct name for this tribe; both names are used regularly. Lamarck & de Candolle published the name 'Cynarocephalae' in 1806 (Reveal, 1997); Cardueae was published by Cassini in 1819 (Solbrig, 1963). The question therefore hinges on whether the '-cephalae' in Cynarocephalae represents a suffix like '-idae' or '-aceae' or whether the name is descriptive of plants with 'heads like Cynara'; if the former, Cynareae has priority from 1806; if the latter, Cynareae was not published until 1830 (and illegitimately so at that) and Cardueae has priority. Botanists still seem to be in the process of duking out which interpretation is corrent, and I suspect that it may take the ICBN stepping in to settle the matter.

**Composite flower heads may contain both 'ray' and 'disk' florets (the little individual flowers). If you think of a daisy, the 'ray' florets are the ones around the edge that carry the large petals while the 'disk' florets are the central ones without petals. Discoid flower heads like those of Cardueae contain only disk florets and no ray florets.


Side view of flower head of Atractylis cancellata, a Mediterranean thistle species in which the rosette of (particularly evil-looking) leaves around the flower head curls upwards to surround it. Photo by Manuel Ramos.

Species of Cardueae most often bring themselves to humanity's attention through the fact that a number of them are significant weed species, and very few Cardueae are regarded with any sort of affection. The Scotch thistle Onopordum acanthium is of course popular in Scotland where it is the national flower; according to legend, a Scottish encampment was saved from a sneak attack by Vikings when one of the invaders yelled out after stepping on a thistle, alerting the sentries to their presence. Also granted a certain regard is Cynara cardunculus, the cardoon/globe artichoke. Earlier classifications recognised two species, the cardoon C. cardunculus grown for its edible stalks and the artichoke C. scolymus grown for its similarly edible flower heads, but there is no doubt that the latter is a horticulturally derived variety of the former. Perhaps the best demonstration of this is that escaped seeds from artichoke fields in California and Australia have given rise to wild populations of 'cardoons' (Sonnante et al., 2007). I will also note that artichokes would also be a feature of my ideal garden - not because I'm a fan of eating artichokes (I think they're pretty tasteless) but because these two-metre tall thistles are such spectacular plants.

And that's all you'll be hearing from me for a little while - five-thirty tomorrow morning, I leave for two weeks in the field. Feel free to talk among yourselves until I get back.

REFERENCES

Beentje, H. J. 2000. The genus Brachylaena (Compositae: Mutisieae). Kew Bulletin 55 (1): 1-41.

Funk, V. A., A. Susanna, T. F. Steussy, & H. E. Robinson. 2009. Classification of Compositae. In Systematics, Evolution, and Biogeography of Compositae (V. A. Funk, A. Susanna, T. F. Stuessy & R. J. Bayer, eds) pp. 171-189. International Association for Plant Taxonomy (IAPT): Vienna.

Panero, J. L., & V. A. Funk. 2008. The value of sampling anomalous taxa in phylogenetic studies: major clades of the Asteraceae revealed. Molecular Phylogenetics and Evolution 47 (2): 757-782.

Reveal, J. L. 1997. Early suprageneric names in Asteraceae. Compositae Newsletter 30: 29-45.

Solbrig, O. T. 1963. Subfamilial nomenclature of Compositae. Taxon 12 (6): 229-235.

Sonnante, G., A. V. Carluccio, R. Vilatersana & D. Pignone. 2007. On the origin of artichoke and cardoon from the Cynara gene pool as revealed by rDNA sequence variation. Genetic Resources and Crop Evolution 54 (3): 483-495.

"Electronic Publication of Nomenclatural Acts is Inevitable"

The Jurassic mecopteran Lichnomesopsyche gloriae, one of six new fossil species not published today. The black line is highlighting the long proboscis; the scale bar represents 10 mm. Image from Ren et al. (2009).

So sayeth Mike Taylor (for my own confused ramblings through the quagmire of electronic publication, read my earlier posts on the subject). And this day presents us with a spectacular demonstration of that point.

In a paper in today's issue of Science, Ren et al. (2009) have presented an analysis of Jurassic to early Cretaceous long-proboscid scorpionflies and their role as probable pollinators of nectar-producing gymnosperms (as has also been suggested for kalligrammatid lacewings). As part of this study, Ren et al. present descriptions of six new species and two new genera of fossil scorpionflies. Nothing out of the ordinary here, except that (Science being Science, with its notorious restrictions on article length) the species descriptions are published in the Supporting Online Material.

From the point of view of the ICZN, Science is a perfectly valid forum for publication - thousands of copies are printed every week. But these printed editions don't include the online supplements, so the online-only component of the journal is currently not a valid publication. Technically speaking, the new species of Ren et al. (which are referred to and illustrated but not described in the print version) are nomina nuda. They are not valid names. But these online-only names have not appeared in some far-flung unfrequented corner of the internet, they have appeared in one of the world's most prominent science journals (like it says on the label). Their validity is going to be pretty much taken for granted.

REFERENCES

Ren, D., C. C. Labandeira, J. A. Santiago-Blay, A. Rasnitsyn, C.-K. Shih, A. Bashkuev, M. A. V. Logan, C. L. Hotton & D. Dilcher. 2009. A probable pollination mode before angiosperms: Eurasian, long-proboscid scorpionflies. Science 326: 840-847.

Name That Bug: Ponopterix axelrodi

Ponopterix axelrodi (from Bechly, 2007).

Obviously I'm going to have to refrain from using fossil insects as ID challenges in future, or at least confiscate Adam Yates' copy of Grimaldi & Engel (2005) before I do so to stop him from identifying them so quickly*.

*Unless, of course, I cruelly exploit Grimaldi & Engel's neglect of Palaeozoic polyneopterans.

Ponopterix axelrodi is a member of the Jurassic to Cretaceous insect family Umenocoleidae from the Lower Cretaceous Crato Formation of Brazil. Umenocoleids were originally described in 1973 as beetles, which they resemble in having the front pair of wings hardened into a pair of elytra (wing covers). However, while elytra are only found in two orders among the Recent insect fauna (beetles and earwigs), umenocoleids represent a third independent origin of elytra and are in fact related to dictyopterans (the clade that includes cockroaches, mantids and termites). The retention of a short ovipositor in Umenocoleidae (visible in the specimen above at the very end of the abdomen) places them just outside crown Dictyoptera, though a position closer to polyphagoid cockroaches has also been suggested (which would imply more than one loss of the ovipositor among dictyopterans).

As Adam pointed out, umenocoleids differ from beetles in that wing venation is still marginally visible on the elytra (among crown-group beetles, the original venation has been completely obliterated) and in the presence of cerci (two tail-like appendages at the end of the abdomen, one on either side of the ovipositor in females; cerci are absent in paraneopteran and holometabolous insects). The anterior light patch at the base of the elytron in the specimen above is also present in another specimen of the same species illustrated in Grimaldi & Engel (2005), so this was the original colour pattern of the animal when it was alive*.

*Don't let the poor reputation of cockroaches put you off - many roaches are very attractive insects, boldly patterned in contrasting colours**.

**Just be careful of the desert cockroaches that walk around with their backsides pointed into the air. If they feel that a potential threat is approaching too close, they can fire a stream of foul-smelling liquid towards it from a pair of abdominal glands. Not pleasant.

Umenocoleids also inspire the one detail in Grimaldi & Engel (2005) that causes me to scream with frustration. In the caption to their photo of Ponopterix axelrodi, G & E make the remark, "Umenocoleid roaches are known from the Late Jurassic to Cretaceous, though a putative living species exist". A living umenocoleid? Tell me more! Unfortunately, Grimaldi and Engel provide no citation for this statement, and I have been unable to find any reference to a living umenocoleid anywhere else. I'm still holding out hope, though.

REFERENCES

Bechly, G. 2007. 'Blattaria': cockroaches and roachoids. In The Crato Fossil Beds of Brazil: window into an ancient world (D. M. Martill, G. Bechly & R. F. Loveridge, eds). Cambridge University Press.

Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press. 755 pp.

Name That Bug # 4

Another fossil for you all. Scale bar is five millimetres; attribution, as always, to follow.

Update: Identity now available here. Photo from Bechly (2007).

Name That Bug: Meioneurites spectabilis

Meioneurites (Parameioneurites) spectabilis (from Engel, 2005).

This image wasn't up ten minutes before being identified by Adam Yates. Meioneurites spectabilis is a member of the Jurassic butterfly-like lacewing family Kalligrammatidae. Kalligrammatids have been featured on Catalogue of Organisms previously.

In the fossil above, you can see that kalligrammatids lacked the coiled proboscis of a butterfly (though their mouthparts are much more elongate than other lacewings, and kalligrammatids were probably nectar feeders like butterflies). Also, if you look very closely at the wings (you'd probably have to zoom in), you may be able to make out that there is a higher density of veins in the wings than in butterflies.



For comparison, here's another kalligrammatid, Sophogramma lii, in a figure from Yang et al. (2009). Pretty.

REFERENCES

Engel, M. S. 2005. A remarkable kalligrammatid lacewing from the Upper Jurassic of Kazakhstan (Neuroptera: Kalligrammatidae). Transactions of the Kansas Academy of Science 108 (1-2): 59-62.

Yang Q., Zhao Y.-Y. & Ren D. 2009. An exceptionally well-preserved fossil kalligrammatid from the Jehol Biota. Chinese Science Bulletin 54 (10): 1732-1737.

Name That Bug # 3

Mr Greenslade, tell the masses what's the challenge:



Perhaps a little easy, but I'm feeling charitable. Size of image about ten centimetres across. Attribution, of course, to follow identification.

Update: The identification post for this image (from Engel, 2005) is now available here.

Cranes Off the Rails (Taxon of the Week: Grues)

The 'Messel rail' Messelornis cristata - a specimen with preserved plumage. Photo from here.

Despite its presentation in years of fieldguides and other popular books, the bird order 'Gruiformes' has in recent times been scattered to the four winds, with analyses both morphological and molecular proclaiming its polyphyly. Nevertheless, molecular analyses such as Hackett et al. (2008) continue to support a clade roughly corresponding to the suborder Grues as recognised by Cracraft (1973)* containing the cranes and the rails. The morphological analysis of Livezey & Zusi (2007) on the other hand, does not support this clade, but it does support monophyly for each of the two primary divisions within Grues, the ralloid and gruoid lineages.

*Just to confuse matters, the name "Grues" has been used by different authors for clades of differing inclusivity. Mayr (2009), for instance, uses "Grues" for the Aramus + Gruidae clade, and refers to the larger clade as "core Gruiformes".

The ralloid line contains the living families Rallidae*, the rails, and Heliornithidae, the finfoots (or should that be finfeet?) Cracraft (1973) regarded the Cretaceous Laornis edvardsianus as a stem ralloid, but no-one else seems to have taken him up on this suggestion. More reliably on the ralloid stem are the Palaeocene to Oligocene Messelornithidae (Mayr, 2009). Messelornithids were medium-sized birds (about the size of a small chicken) best known from Messelornis cristata for which over 500 specimens are available, some even with preserved feathering. Messelornis was highly terrestrialised with limited flight capabilities and almost ludicrously long legs (loss or reduction of flight has been a common occurrence among the Grues). Its beak was relatively short and the overall appearance of Messelornis would probably have not been dissimilar to the modern cariamas.

*Hackett et al. (2008) resolved the Rallidae as paraphyletic to Heliornithidae, with Sarothrura (the flufftails) closer to Heliornis than to the other two included rails Himantornis and Rallus. A few places, at least online, have suggested recognising Sarothrura as a separate family from the Rallidae as a result, but I'd recommend waiting for a more detailed analysis with greater coverage of the Rallidae. Increased taxonomic coverage may return the flufftails to the other Rallidae, or it may make it more appropriate to treat the finfoots as derived rallids.


The sungrebe Heliornis fulica of tropical South America (I tried to find a picture of one carrying chicks, but no luck). Photo by Jerry Oldenettel.

The finfoots of the Heliornithidae are three species (one in Asia, one in Africa, one in South America) of tropical grebe-like birds, renowned for their reclusiveness. The South American sungrebe Heliornis fulica is the most distinctive in appearance of the three species (though mitochondrial analysis indicates that it and the Asian Heliopais personata form a clade to the exclusion of the African Podica senegalensis - Fain et al., 2007) and is also very distinct in its nesting behaviour. Heliopais and Podica, like most aquatic birds, have chicks that hatch out reasonably well-developed and immediately able to swim after their parents. Heliornis, in contrast, has altricial chicks that hatch out after only ten to eleven days of incubation. The really amazing bit, though, is what happens after the chicks hatch. The male sungrebe has a shallow pouch under each wing and he is able to transport the chicks inside this pouch, even flying with them. Whether the chicks remain in the pouches permanently or whether they are only placed in them while the male is travelling remains unknown. Funnily enough, while this chick-carrying behaviour was described by Alvarez del Toro in 1971, it had originally been recorded almost 140 years earlier by Prince Maximilian of Wied. It seems that everyone else had assumed the prince was smoking something.


Grey-winged trumpeters, Psophia crepitans. Photo by A. Vinot.

The gruoid lineage includes Psophia, the trumpeters, Aramus guarauna, the limpkin, and Gruidae, the cranes, as well as the fossil taxa Parvigrus pohli, Geranoididae and Eogruidae. Most recent authors agree that Aramus and Gruidae form a clade to the exclusion of Psophia. The chicken-sized Oligocene Parvigrus was originally described by Mayr (2005) as sister to Aramus + Gruidae, but he later (Mayr, 2009) revised its position to stem gruoid. Parvigrus lacked the long beak of limpkins and cranes, as do the Recent trumpeters, three species of similarly chicken-sized birds found in northern South America.

Whether Geranoididae and Eogruidae possessed crane-like long beaks is an unknown factor as skull material for both has not been found. Cracraft (1973) placed both outside the crown gruoids, but Clarke et al. (2005) placed Eogruidae inside the gruoid crown as sister to Aramus + Gruidae. The Eocene Geranoididae have been described only from leg bones (Wetmore, 1933, assigned some wing bones to Geranoides jepseni in his original description of this species but did not describe them) so little can be said about them except that they were large and long-legged. Wetmore (1933) commented on the unusually wide spacing of the trochleae (the 'knuckles') at the end of the tarsometatarsus suggesting that Geranoides had very widely splayed toes, but Cracraft (1969) later attributed to wide spacing to post-mortem distortion. Cracraft (1969, 1973) included a number of Eocene birds in the Geranoididae but admitted a lack of derived characters uniting them; Geranoididae may represent a paraphyletic assemblage of basal gruoids.


Distal ends of tarsometatarsi of the eogruids Proergilornis and Ergilornis, showing reduction of the inner trochlea in Proergilornis and its loss in Ergilornis. Figure from Cracraft (1973).

The Eocene to Pliocene Eogruidae were also decent-sized long-legged birds from central Asia and (in later times) Europe. Earlier authors recognised two families, Eogruidae and Ergilornithidae, but 'ergilornithids' are now recognised as derived eogruids. Eogruids were highly cursorial birds and a humerus attributed to Ergilornis suggests that it was flightless, though the earlier Eogrus aeola shows no sign of being so (Clarke et al., 2005). Originally three-toed, eogruids showed a reduction in the size of the inner toe, and Ergilornis and Amphipelargus (the latest of the eogruids) lost it entirely (it is easy to present a progression from flying and three-toed to flightless and two-toed, but be warned that three-toed species survived into the Miocene, well after the appearance of the two-toed forms). The only other birds to reduce the number of toes to two are the ostriches, and a relationship between ostriches and eogruids has been suggested in the past (generally in association with the idea that the ratites do not form a monophyletic group). However, Cracraft (1973) confirmed that eogruids were more similar in their fine morphology to gruoids than ostriches, and modern phylogenetic analyses do not support a close relationship of ostriches and gruoids.

Many people carry the impression that flightlessness in birds is associated with lack of predators. However, eogruids evolved flightlessness in an environment in which predators were no rarity (amongst others, they shared their world with such horrors as hyaenodonts and entelodonts*). Similarly, while the exact circumstances in which they became flightless is unknown, modern ostriches (Africa), emus (Australia) and rheas (South America) all live alongside significant predators or at least did so until recently. Obviously, something other than lack of predators is at play here.

*I always imagine Roald Dahl's hornswogglers to be something like an entelodont.

REFERENCES

Clarke, J. A., M. Norell & D. Dashzeveg. 2005. New avian remains from the Eocene of Mongolia and the phylogenetic position of the Eogruidae (Aves, Gruoidea). American Museum Novitates 3494: 1-17.

Cracraft, J. 1969. Systematics and evolution of the Gruiformes (class, Aves). 1, The Eocene family Geranoididae and the early history of the Gruiformes. American Museum Novitates 2388: 1-41.

Cracraft, J. 1973. Systematics and evolution of the Gruiformes (class Aves). 3, Phylogeny of the suborder Grues. Bulletin of the American Museum of Natural History 151: 1-127.

Fain, M. G., C. Krajewski & P. Houde. 2007. Phylogeny of "core Gruiformes" (Aves: Grues) and resolution of the limpkin–sungrebe problem. Molecular Phylogenetics and Evolution 43: 515-529.

Hackett, S. J., R. T. Kimball, S. Reddy, R. C. K. Bowie, E. L. Braun, M. J. Braun, J. L. Chojnowski, W. A. Cox, K.-L. Han, J. Harshman, C. J. Huddleston, B. D. Marks, K. J. Miglia, W. S. Moore, F. H. Sheldon, D. W. Steadman, C. C. Witt & T. Yuri. 2008. A phylogenomic study of birds reveals their evolutionary history. Science 320: 1763-1768.

Livezey, B. C., & R. L. Zusi. 2007. Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion. Zoological Journal of the Linnean Society 149 (1): 1-95.

Mayr, G. 2005. A chicken-sized crane precursor from the early Oligocene of France. Naturwissenschaften 92: 389-393.

Mayr, G. 2009. Palaeogene Fossil Birds. Springer.

Wetmore, A. 1933. Fossil bird remains from the Eocene of Wyoming. Condor 35: 115-118.