Name the Bug # 49

You said we'd go far
in my white convertable car.
Reclining my seat;
leaning back in this heat.

Heat is the subject on everyone's mind in this part of the world, as Perth suffers through what is likely to be the longest extended period of temperatures above 30°C on record. So here's a bit of hot pink for today's ID challenge:




Attributions to follow.

Update: Identity available here. Photos from here and here.

How to Wipe Out a Family

Male Megalopsalis, probably M. eremiotis, photographed in Victoria by Kennedy H.

Taylor, C. K. 2011. Revision of the genus Megalopsalis (Arachnida: Opiliones: Phalangioidea) in Australia and New Zealand and implications for phalangioid classification. Zootaxa 2773: 1-65.

A morphological phylogenetic analysis is conducted of Australasian harvestmen previously included in the family Monoscutidae. Monophyly of Monoscutidae is not supported, and the subfamilies Monoscutinae and Megalopsalidinae are synonymised with the South American subfamily Enantiobuninae. Monoscutidae is re-synonymised with the family Neopilionidae. The analysis also demonstrates the polyphyly of species previously assigned to the genus Megalopsalis. Megalopsalis epizephyros new species, M. eremiotis new species, M. leptekes new species and M. pilliga new species are described and M. serritarsus and M. hoggi are redescribed, all from Australia. Hypomegalopsalis tanisphyros new genus and species is described from Western Australia. Megalopsalis linnaei is transferred to Tercentenarium new genus. Forsteropsalis new genus is established to include species from New Zealand (including Auckland Island): Macropsalis chiltoni (type species), Pantopsalis distincta, Macropsalis fabulosa, Pantopsalis grayi, Megalopsalis grimmetti, Megalopsalis inconstans, Megalopsalis marplesi, Megalopsalis nigra and Pantopsalis wattsi.

One of the quirks of my PhD thesis was that, by the time I'd finished, it seemed that the family of harvestmen I'd chosen to work on didn't actually exist. My reasons for coming to that conclusion are presented in a paper published today.

The paper has two major components: one is a taxonomic revision of the genus Megalopsalis, the other is a phylogenetic analysis of what had been the family Monoscutidae. Because phylogenetic analyses of long-legged harvestmen are few and far between (in fact, I'm only aware of one earlier morphology-based numerical analysis), analysing the phylogeny of Monoscutidae required me to also analyse exemplars from other families of long-legged harvestmen, just to make sure that the Monoscutidae could be supported as monophyletic.



Which it couldn't. When the results of the analysis came back to me, I saw that they had nested the South American Thrasychirus well within the Monoscutidae (everything from Spinicrus nigricans downwards in the tree above, reproduced from the paper, which is a consensus of a number of analyses done under varying parameters). Thrasychirus has not been previously regarded as a monoscutid, though Hunt & Cokendolpher (1991) had suggested that a relationship between the two was not outside the realms of possibility. Instead, Thrasychirus has been placed in the Enantiobuninae, treated as a subfamily of the family Neopilionidae. As well as the Enantiobuninae, Neopilionidae includes Neopilio australis, a species without close relatives from South Africa, and Ballarrinae, a group of tiny harvestmen with extraordinarily long palps found in Australia, South Africa and South America.


Male Forsteropsalis, probably F. inconstans, photographed by Alan Macdougall.

For a few reasons, I'm a little skeptical of the exact position of Thrasychirus in the above tree. The relationships between taxa were not strongly supported, and a couple of features of Thrasychirus look as if they may be consistent with a more basal position. Most notably, in most families of long-legged harvestmen the tarsus of each leg is divided into a basitarsus and distitarsus, with a distinct hinge allowing easy bending at the junction between the two. In most 'Monoscutidae', this hinge has disappeared and the junction between the two parts of the tarsus is fixed in a straight line. However, Thrasychirus (as well as Australiscutum, which I talked about in an earlier post) has a mobile hinge. However, whatever the exact position of Thrasychirus may turn out to be, I feel reasonably confident that the combination of 'Monocutidae' and Enantiobuninae will continue to be supported—in particular, the two share a unique spiracle morphology that has not been recorded from other families—and so I chose to recognise this clade as a single taxon. Enantiobuninae happens to be an older name than Monoscutidae, so it that was the name I had to use. In most analyses, this expanded Enantiobuninae was nested within a clade also including the other Neopilionidae*, so I chose to continue to treat Enantiobuninae as a subfamily of Neopilionidae.

*The exception was the analysis conducted with all characters given equal weighting, which gave some somewhat suspicious results (it failed to recover monophyly for some taxa that have been universally accepted in the past). It is my suspicion that these odd results were mainly due to the single included example of Ballarrinae; ballarrines have some features convergent with the Dyspnoi, another group of harvestmen, and these characters tended to pull the ballarrine towards the Dyspnoi. I have a manuscript currently in preparation that indicates that these unexpected results disappear as more taxa are included in the analysis.


The holotype of Hypomegalopsalis tanisphyros.

Most other results in the paper are reasonably straightforward. The genus Megalopsalis as recognised to date appears to be polyphyletic; in particular, the New Zealand species previously included in that genus have been moved to a new genus, Forsteropsalis, and are probably more closely related to other New Zealand enantiobunines in the genus Pantopsalis. The Western Australian Megalopsalis linnaei, a definite oddball among the Enantiobuninae, also gets its own genus Tercentenarium. And another new Western Australian species gets its own new genus in Hypomegalopsalis tanisphyros.

Let me be up front and say that I do not regard the establishment of Hypomegalopsalis as one of my greatest achievements. One of the failings of the binomial system of nomenclature, in my opinion, is that it doesn't really allow for uncertainty. Including a new species in a pre-existing genus effectively makes a statement that that species is more closely related to the members of that genus than any other. On the other hand, many taxonomists would see the erection of a new genus as a statement that its member(s) are significantly different from those of pre-existing genera. In the case of tanisphyros, my initial expectation was that it would turn out to be a small species of Megalopsalis. However, none of the analyses I conducted supported such a clade. To include tanisphyros in Megalopsalis and keep the genus supported as monophyletic, I would have probably had to also include the heavily sclerotised species previously included in the 'Monoscutinae', which would have made the single genus Megalopsalis more morphologically disparate than probably the entire remaining Phalangioidea. If it was possible to describe a new species without placing it in a genus, I would have done so for tanisphyros, but the binomial system does not allow for such things. Placing it in a separate genus seemed the least objectionable option. Still, if anyone conducts a further study in the future that supports quashing Hypomegalopsalis, I won't be protesting.

REFERENCE

Hunt, G. S., & J. C. Cokendolpher. 1991. Ballarrinae, a new subfamily of harvestmen from the Southern Hemisphere. Records of the Australian Museum 43: 131–169.

Southern Snakes at Sea

Bandy-bandy, Vermicella annulata, either engaged in an alarm display or participating in a game of croquet. Photo from here.

The front-fanged snakes are a distinctive clade distinguished, as it says on the label, by their well-developed venom-injecting fangs at the front of the mouth. For a long time, the front-fanged snakes were treated as two families, the terrestrial Elapidae and the sea snakes of the Hydrophiidae. However, it has become well-established that the sea snakes are derived from within the Elapidae, and 'Hydrophiidae' became the elapid subfamily Hydrophiinae. As well as its original quota of sea snakes, the Hydrophiinae also now includes the Australo-Papuan species of terrestrial Elapidae. The sea snakes, as it turns out, are not monophyletic within the Hydrophiinae: the sea kraits of the genus Laticauda form the sister group to other hydrophiines, while the remaining sea snakes form a deeply-nested clade (the Hydrophiini) within the terrestrial hydrophiines (Sanders et al. 2008).


Yellow-lipped sea krait Laticauda colubrina, from here.

Sea kraits differ from hydrophiin sea snakes in that they still spend part of their lives on land. They hunt and feed aquatically, mostly on eels, with females catching larger, deeper-living prey than males and juveniles (Shine & Shetty 2001). However, after feeding they tend to return to land to digest their prey. Sea kraits also mate and lay their eggs on land. One possible exception has been claimed for the Rennell Island sea krait Laticauda crockeri which, being restricted to an brackish inland lake on Rennell Island in the Solomons, is also one of the few freshwater sea kraits. Laticauda crockeri has never been recorded on land, and the local people claim that it produces live young, reporting that young can be found within females. In contrast, a sympatric population of the more widespread yellow-lipped sea krait L. colubrina is correctly reported by Rennell Islanders as a terrestrial egg-layer. Unfortunately, Cogger et al. (1987) failed to collect gravid females in their study of L. crockeri and were unable to confirm the local reports.


Yellow-bellied sea snake Pelamis platurus photographed off Costa Rica by Zoltan Takacs.

Hydrophiins, in contrast, are truly marine, bearing live young and unable to move on land. Both sea kraits and hydrophiins have deep paddle-shaped tails, but the tail of hydrophiins differs from that of sea kraits in being supported by extensions of the vertebral apophyses. Sea snakes are widely recognised as among the most venomous of living snakes, but are also known as mostly unlikely to bite humans (different species, of course, exhibit different levels of agression); sea snakes do not even necessarily inject venom when they do bite (Senanayake et al. 2005). Two notable exceptions to the high venom strength of most sea snakes are the marbled sea snake Aipysurus eydouxii and the turtle-head sea snake Emydocephalus annulatus, both specialist feeders on fish eggs. Fish eggs, of course, do not tend to put up much of a fight, and the venom strength of these species is less than one-fiftieth that of other sea snakes (Li et al. 2005). They also have reduced fangs and poison glands, but on the other hand they do have stronger throat muscles (improving their suction).


Western brown snake Pseudonaja mengdeni, photographed by Dan Lynch.

Among the terrestrial hydrophiines, the Hydrophiini are most closely related to a clade of viviparous species including, among others, the tiger snakes Notechis and the Australian copperheads Austrelaps (Sanders et al. 2008). The origin of viviparity in Hydrophiinae remains unsettled. Scanlon & Lee (2004) found support, albeit low, for a single viviparous clade, but Sanders et al. (2008) found three independent viviparous clades—the large-bodied viviparous clade just mentioned, a second clade of smaller snakes such as the ornamental snakes Denisonia and the hooded snakes Suta, and the death adders Acanthophis as a third clade—but were unable to significantly reject monophyly. Similarly, Scanlon & Lee (2004) posited a single origin for burrowing hydrophiines such as the Vermicella pictured at the top of this post (a specialised predator of Typhlopidae blind snakes), but Sanders et al. (2008) supported two separate clades with Vermicella distant from other burrowing taxa. One thing they did agree on was a close relationship between the brown snakes Pseudonaja and the taipans Oxyuranus.

Offhand, in case anyone was hoping that a post on elapids might lead me to a discussion of the... ahem... works of one Raymond Hoser: at one point, I would indeed have happily delved into the subject. But I have to confess that, as time marches on, I find myself increasingly sympathetic to C. T. Simpson's dismissal of the Nouvelle École: "Life is too short and valuable to be wasted in any attempt at deciphering such nonsense".

REFERENCES

Cogger, H., H. Heatwole, Y. Ishikawa, M. McCoy, N. Tamiya & T. Teruuchi. 1987. The status and natural history of the Rennell Island sea krait, Laticauda crockeri (Serpentes: Laticaudidae). Journal of Herpetology 21 (4): 255-266.

Li, M., B. G. Fry & R. M. Kini. 2005. Eggs-only diet: its implications for the toxin profile changes and ecology of the marbled sea snake (Aipysurus eydouxii). Journal of Molecular Evolution 60: 81-89.

Sanders, K. L., M. S. Y. Lee, R. Leys, R. Foster & J. S. Keogh. 2008. Molecular phylogeny and divergence dates for Australasian elapids and sea snakes (Hydrophiinae): evidence from seven genes for rapid evolutionary radiations. Journal of Evolutionary Biology 21 (3): 682-695.

Scanlon, J. D., & M. S. Y. Lee. 2004. Phylogeny of Australasian venomous snakes (Colubroidea, Elapidae, Hydrophiinae) based on phenotypic and molecular evidence. Zoologica Scripta 33 (4): 335-366.

Senanayake, M. P., C. A. Ariaratnam, S. Abeywickrema & A. Belligaswatte. 2005. Two Sri Lankan cases of identified sea snake bites, without envenoming. Toxicon 45 (7): 861-863.

Shine, R., & S. Shetty. 2001. Moving in two worlds: aquatic and terrestrial locomotion in sea snakes (Laticauda colubrina, Laticaudidae). Journal of Evolutionary Biology 14: 338-346.

Name the Bug # 48

What is this animal and what is it doing?



Attribution (as always) to follow.

Update: Identity now available here. Photo from here.

Pomfrets of the High Seas

The fanfish Pterycombus petersii, photographed off the Kerama Islands by Kazuo Kayama.

The Bramidae, commonly known as pomfrets, are a cosmopolitan family of pelagic fishes, found mostly in the upper layers of the world's oceans. Pomfrets are teardrop- or elliptical-shaped, deep-bodied and strongly-compressed fish with a single long dorsal fin that is ventrally mirrored by (usually slightly shorter) similar-shaped anal fin. Some species are quite large, with about a metre as the maximum recorded length for the family (McEachran & Fechhelm 2006). Thompson (2002) stated that pomfrets feed on other fish and larger invertebrates such as squid, but García & Chong (2002) found that Brama australis fed primarily on crustaceans such as krill.


Pteraclis aesticola, photographed by Kanno Takayuki.

The Bramidae are divided between two subfamilies, Pteraclinae and Braminae, though the monophyly of the latter in particular does not necessarily appear to have been established. Pteraclinae include two genera, the fanfishes Pteraclis and Pterycombus, with particularly large triangular dorsal and anal fins. Despite their unwieldy appearance, these fins can be completely depressed into a special groove formed by modified scales running on either side of the fins, as is being done by the individual in the photo above (if expanded, the fins of Pteraclis are even more expansive than those of Pterycombus, with the dorsal fin extending all the way forward to the snout). Members of the Braminae (the genera Brama, Eumegistus, Taractes, Taractichthys and Xenobrama) have less flamboyant fins with scales running partway along the rays and unable to be depressed (Thompson 2002).


The large bramine Taractes rubescens, from here.

Phylogenetically speaking, the molecular study using by Li et al. (2009) placed the Bramidae among a clade that they referred to as Stromateoidei (though somewhat different from earlier uses of this name), that also included families such as Stromateidae (butterfishes), Scombridae (mackerels), Trichiuridae (cutlassfishes) and Chiasmodontidae (black swallowers). A comparable clade was also recovered by Yagishita et al. (2009) using different molecular markers (Li et al. used nuclear genes; Yagishita et al. used mitochondrial genes; however, Yagishita et al. sampled a smaller number of families than Li et al.). Though morphologically diverse, all families in this clade are primarily pelagic.

REFERENCES

García M., C., & J. Chong. 2002. Composicion de la dieta de Brama australis Valenciennes 1837 en la zona centro-sur de Chile (VIII región) en Otoño 2000 y Verano 2001. Gayana 66 (2): 225-230.

Li, B., A. Dettaï, C. Cruaud, A. Couloux, M. Desoutter-Meniger & G. Lecointre. 2009. RNF213, a new nuclear marker for acanthomorph phylogeny. Molecular Phylogenetics and Evolution 50: 345-363.

McEachran, J. D., & J. D. Fechhelm. 2006. Fishes of the Gulf of Mexico, vol. 2. University of Texas Press.

Thompson, B. A. 2002. Bramidae: pomfrets. In: Carpenter, K. E. (ed.) The Living Marine Resources of the Western Central Atlantic, vol. 3. Bony fishes part 2 (Opistognathidae to Molidae), sea turtles and marine mammals. FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists Special Publication 5. Food and Agriculture Organization of the United Nations: Rome.

Yagishita, N., M. Miya, Y. Yamanoue, S. M. Shirai, K. Nakayama, N. Suzuki, T. P. Satoh, K. Mabuchi, M. Nishida & Tetsuji Nakabo. 2009. Mitogenomic evaluation of the unique facial nerve pattern as a phylogenetic marker within the percifom fishes (Teleostei: Percomorpha). Molecular Phylogenetics and Evolution 53 (1): 258-266.

Name the Bug # 47

Potentially a bit of an easy one today. Anyone know what this is?



Attribution to follow.

Update: Identity now available here. Photo from here.

Triassic, Glorious Triassic

Daonella frami, from Schatz (2004).

The Halobiidae were a family of bivalves that first made their appearance in the lower Middle Triassic (mid-Anisian, for those who are, unlike yours truly, conversant with such things). They were a specifically Triassic event, taking their bow towards the end of the period, and during that time they managed to fit in four roughly successive genera (with some overlap), Enteropleura, Daonella, Aparimella and Halobia, with Daonella and Halobia particularly speciose. Each of these genera is believed to have been ancestral to the next, except that Halobia may have arisen from Aparimella, from Daonella, or possibly polyphyletically from both (Chen & Stiller 2010). Within the larger genera Daonella and Halobia, the rate of species turnover was very high. This, together with their wide distribution at the time, has led to halobiids being the focus of numerous biostratigraphic studies, the Triassic being a time period somewhat poor in really good stratigraphic markers. Unfortunately, distinguishing the recognised species of halobiid is no easy task; for instance, it is estimated that there are roughly ten times as many available species names in Halobia than there are actual valid species (McRoberts 2010).

Halobiids have been commonly referred to as 'flat clams', and they were certainly that. Even the thickest Daonella were never more than 0.2 times as thick as they were tall* (Schatz 2005). Their shells were also very thin compared to other bivalves. The genera are distinguished by the main ornamentation and also by the morphology of the posterior auricle, a tubular fold towards the dorsal margin of the shell. Daonella has prominent radial ornamentation and lacks an auricle (except for the early and probably basalmost species Daonella fengshanensis which possessing a small auricle retained from the ancestral Enteropleura: Chen & Stiller 2010). The auricle reappeared with Aparimella and Halobia, the latter of which had a double auricle (McRoberts 2000).

*For those unfamiliar with bivalve orientation, the two shells are treated as left and right, with the umbo (the pointy bit where the shells join) at the top.


Reconstruction of live Daonella, from Schatz (2005).

Daonella fossils have generally been found in black shales, commonly believed to indicate anoxic environments and hence not their original habitat when alive (Schatz 2005). The most popular suggestion for the original mode of life of Daonella has been that they were pseudoplanktonic, living attached to floating wood or larger nektic animals such as ammonites. However, Schatz (2005) pointed out that such a mode of life would not have been possible for Daonella as they appeared to lack any means of attaching themselves to a substrate; unlike attached bivalves such as mussels, they lack an opening in the shell where a byssus could have been extruded (for those familiar with opening mussels, that would be the soft part near the hinge where you can slide in a knife). Nor is the roughly circular shape of a halobiid suitable for a life embedded in the substrate. Instead, Schatz suggested that Daonella lived lying on the top of the soft mud that eventually became the shales. The original belief that this environment was completely anoxic was incorrect, though it would have still been very low in oxygen, an environment in which many bivalves can be found living today. The round, flat shape of Daonella would have allowed it to 'float' on the mud, while the high surface area-volume ratio would have decreased its oxygen demands relative to supply.

REFERENCES

Chen, J.-H., & F. Stiller. 2010. An early Daonella from the Middle Anisian of Guangxi, southwestern China, and its phylogenetical significance. Swiss Journal of Geosciences 103 (3): 532-533.

McRoberts, C. A. 2000. A primitive Halobia (Bivalvia: Halobioidea) from the Triassic of northeast British Columbia. Journal of Paleontology 74 (4): 599-603.

McRoberts, C. A. 2010. Biochronology of Triassic bivalves. In: Lucas, S. G. (ed.) The Triassic Timescale. Geological Society, London, Special Publications 334: 201-219.

Schatz, W. 2004. Revision of the genus Daonella (Arzelella) (Halobiidae; Middle Triassic). Journal of Paleontology 78 (2): 300-316.

Schatz, W. 2005. Palaeoecology of the Triassic black shale bivalve Daonella—new insights into an old controversy. Palaeogeography, Palaeoclimatology, Palaeoecology 216 (3-4): 189-201.

Name the Bug # 46

Attribution to follow.

Update: Identity now available here. Figure from Schatz (2004).

Ground Beetles for Today

European zuphiin Polystichus connexus, by Cristoph Benisch.

The subject of today's post is a group of ground beetles (Carabidae) that has been treated in the past as the subfamily Zuphiinae, but seems to now be more commonly treated as a supertribe Zuphiitae within the Harpalinae. Whatever their appropriate formal name, the zuphiites are distinguished by a relatively long and thick scape (the first major segment of the antennae) and spination on the first stylomere of the female's ovipositor (Ball 1985; Ober & Maddison 2008); the clade is also supported by molecular data (Ober & Maddison 2008). Many zuphiites also have a relatively narrow pronotum (noticeably longer than wide) and truncate elytra. Species of Zuphiitae are found around the world, primarily in the tropics, with known centres of diversity in Australia and the Neotropics (Baehr 1985). Diversity in Asia and Africa is supposedly lower but, as most of the Australian taxa appear to be ultimately derived through immigrations from Asia (Baehr 1985), it would not be at all surprising if this distribution was biased by higher levels of study in the former continents*.

*Though 'higher level of study' is definitely a relative term: the Australian fauna, for instance, seems to owe its recognised diversity overwhelmingly to the work of Martin Baehr alone.


The galeritin Trichognathus marginipennis, photographed by Guilherme Ide.

Within the Zuphiitae, current classifications recognise the tribes Zuphiini, Anthiini, Galeritini, Dryptini, Helluonini and Physocrotaphini, though the monophyly of some of these tribes is not firmly established (Ober & Maddison 2008). The Zuphiini are distinguished by a particularly long scape, while the Galeritini possess asymmetrically dilated tarsi in the males (Baehr 1985).

REFERENCES

Baehr, M. 1986. Revision of the Australian Zuphiinae. 6. The genus Planetes Macleay. Supplement to the other genera (Insecta, Coleoptera, Carabidae). Spixiana 9 (2): 151-168.

Ball, G. E. 1985. Reconstructed phylogeny and geographical history of genera of the tribe Galeritini (Coleoptera: Carabidae). In: Ball, G. E. (ed.) Taxonomy, Phylogeny and Zoogeography of Beetles and Ants: A volume dedicated to the memory of Philip Jackson Darlington, Jr. (1904-1983) pp. 276-321. D. W. Junk Publishers.

Ober, K. A., & D. R. Maddison. 2008. Phylogenetic relationships of tribes within Harpalinae (Coleoptera: Carabidae) as inferred from 28S ribosomal DNA and the wingless gene. Journal of Insect Science 8 (63): 1-32.