Neostrinatina mixoppia

Dorsum of Neostrinatina mixoppia, from Mahunka (1978).

Time for another oribatid. This is Neostrinatina mixoppia, a species described as the only member of its genus by S. Mahunka in 1978. It was described on the basis of two specimens from near Coban in the highlands of Guatemala. Neostrinatina belongs to the family Oppiidae, a group of often smaller oribatids with moniliform legs, and is a bit over a quarter of a millimetre in length. N. mixoppia noticeably differs from other oppiids in its long pectinate sensillus on either side of the prodorsum. The other dorsal setae are also particularly long and barbed. Other distinctive features of this species, according to Mahunka, are a pair of lateral teeth on the dorsosejugal suture (the junction between the prodorsum and the notogaster, or what one might think of as the 'head' and 'body' regions of the dorsum) that jut towards the sensilli, and an 'enormous, spiniform excrescence' projecting forwards from the anogenital region. I must admit, though, I've been trying to interpret Mahunka's illustration of the ventral region of N. mixoppia and I'm still not entirely sure what this latter feature looks like. Like other oppiids, the prodorsum does not have the projecting lamellae found in many oribatid families; instead, N. mixoppia has a pair of branching costulae (thickened ridges). The legs each end in a single claw.

Venter of Neostrinatina mixoppia, from Mahunka (1978).

Oppiids are currently recognised as the most diverse family of oribatids with over 1000 known species, the greater number of these found in the tropics. Though the ecology of N. mixoppia itself is unknown, other oppiids feed on fungi. The single claws on the legs suggest a terrestrial habitat. As with many (if not most) oribatid groups, the relationships of oppiids are in great need of revision with many genera being arranged on the basis of potentially convergent characters. Mahunka himself recognised this in his description of N. mixoppia, expressing the opinion that it represented '? mixture of at least three present day " genera"'. The number of dorsal setae suggested one genus, the dorsosejugal teeth suggested another. Perhaps one day we'll know which is which.

REFERENCE

Mahunka, S. 1978. Neue und interessante Milben aus dem Genfer Museum XXV. On some oribatids collected by Dr. P. Strinati in Guatemala (Acari: Oribatida). Acarologia 20 (3): 133–142.