Pseudotremia peponocranium, Shear, William A., 2011

Shear, William A., 2011, Cave millipeds of the United States. X. New species and records of the genus Pseudotremia Cope. 2. Species from Virginia, USA (Diplopoda, Chordeumatida, Cleidogonidae), Zootaxa 3109, pp. 1-38 : 16

Pseudotremia peponocranium , n. sp.

Figs. 34–39

Types: Male holotype and female paratypes from Giant Caverns, near Narrows, Giles Co., VIRGINIA, collected 7 May 1991 by D. Hubbard.

Diagnosis: No other species of Pseudotremia , and indeed no other milliped species known to me, has the enormously swollen cranium (figs. 34, 35) seen in both males and females of this species.

Etymology: The species epithet, a coined Latin word meaning “pumpkin head” is a noun in apposition. Suggested vernacular name: Pumpkin-headed Cave Milliped.

Description: Male holotype about 15 mm long, 1.6 mm wide, third antennal segment 0.9 mm long. Under light microscope appearing eyeless, but SEM reveals five or six much reduced ocelli on each side, well-separated, unpigmented and of various sizes, the smallest only 20 µm in diameter. Head with enormously enlarged and projecting cranium (fig. 34, 35). Segmental shoulders pronounced on anterior segments but quickly reduced posteriorly so that midbody segments are cylindrical; metazonites smooth and shining (fig. 36). Entirely without pigment.

Gonopods (figs. 37–39) relatively small; angiocoxites tightly appressed nearly all their length, slightly diverging distally; MAPs distally flared laterally, with small, subtriangular subapical spine, apical spine absent; LAPs large, basally broad, evenly curved, undivided. Colpocoxites much reduced, apically bilobed, fused nearly all their length; median colpocoxite processes absent. Ninth legpair typical of troglobionts, femur and three apical segments fused, coxoprefemur with paired basal knobs, distally swollen.

Female similar to male, but swollen cranium less obvious.

Additional record: VIRGINIA: Giles Co.: Wolf Creek Cave, collected by T. L. Brown (no date), 3, ƤƤ.

Notes: This is surely the most distinctive of all Pseudotremia species as the only one with projecting, greatly swollen heads. At first I suspected the enlarged head might be due to some sort of parasite, but found that all collected males and females of this species had them, whilst they were lacking in juveniles. Dissection revealed a mass of undifferentiated tissue (perhaps due to poor preservation) and no sign of a nematode or an insect larva. Thus present evidence supports the conclusion that these monstrous deformities are normal to the species. The sexual dimorphism of the heads suggests some kind of function associated with courtship or copulation, but I could not even begin to speculate what that might be. Pseudotremia peponocranium is a highly adapted troglobiont. Giant Caverns, the type locality, is a former commercial cave that had closed before 1975 ( Holsinger 1975). The exact location of Wolf Creek Cave is unknown to me.

Figures

FIGURES 32 – 38. New species of Pseudotremia. Figs. 32, 33, Pseudotremia orndorffi, n. sp. Fig. 32, gonopods, anterior view; lap, lateral angiocoxal process; map, median angiocoxal process. Fig. 33, gonopods, lateral view; labels as in fig. 32, and dcp, dorsal colpocoxite process; vcp, ventral colpocoxite process. Figs. 34 – 38, P. peponocranium, n. sp. Fig. 34, head of male, frontal view. Fig. 35, head of male, lateral view. Fig. 36, diplosegment, dorsal view. Fig. 37, gonopods, anterior view. Fig. 38, gonopods, lateral view.

FIGURES 39 – 45. New species of Pseudotremia. Fig. 39, gonopods of Pseudotremia peponocranium, n. sp., ventral view. Figs. 40 – 45. Pseudotremia glaber, n. sp. Fig. 40, ocelli. Fig. 41, metazonite, dorsal view. Fig. 42, female genitalia, ventral view. Fig. 43, gonopods, anterior view. Fig. 44, gonopods, ventral view. Fig. 45, right ninth leg, anterior view.