Trigenotyla blacki, Shear, William A., 2003

Shear, William A., 2003, The milliped family Trichopetalidae, Part 1: Introduction and Genera Trigenotyla Causey, Nannopetalum n. gen., and Causeyella n. gen. (Diplopoda: Chordeumatida, Cleidogonoidea), Zootaxa 321, pp. 1-36 : 22-24

Trigenotyla blacki , n. sp.

Figs. 13–15

Types: Male holotype, one male and two female paratypes from Stansbury­January Cave, 4 mi. N of Colcord, Delaware Co., Oklahoma, collected 13 January 1971 by J. H. Black (FSCA). The following specimens are paratypes: OKLAHOMA: Delaware Co.: Jail House Cave, 3 mi. N of Choleta, 1 January 1971, J. H. Black, juvenile; Bell’s Bluff Cave, 5 mi. S of Jay, 14 July 1971, J. H. Black, male; Twin Cave, 5 mi. W, 3 mi. S of Jay, 29 November 1970, J. H. Black, female. Adair Co.: Cave #AD­14, 11 January 2003, G. Graening, D. Fenolio, male.

Diagnosis: The gonopod has ensiform setae like T. parca , but lacks an ectal coxite. Trigenotyla blacki has fewer ocelli, which are depigmented and in only two rows.

Etymology: for the collector, Jeffrey H. Black, recognizing his contributions ( Black, 1971) to the biospeleology of Oklahoma.

Male holotype: Length, 6.5 mm, width 0.9 mm. Color pale yellowish, unmarked. Segmental shoulders moderate; segmental setae to 80% body width. Eight to eleven ocelli, not pigmented, irregular in size and well­separated, in two rows (typically of 6–7 and 3 ocelli). Pregonopodal legs somewhat more crassate than postgonopodal legs, legpairs 6 ( Fig. 15 ), 7 largest; prefemora of 6 curved, with basal swelling.

Gonopods ( Fig. 13 ) much as described for T. parca , but setae somewhat less ensiform, more clearly socketed, lateral group not raised on ectal shoulder; ectal coxites absent, mesal coxites more robust, fimbriate branch prominent. Legpair 9 ( Fig. 14 ) as for T. parca ; legpairs 10, 11 with glands, otherwise unmodified.

Female paratype: Length, 6.4 mm, width 0.85 mm. Nonsexual characters as in male.

Distribution: Known only from caves in Delaware and Adair Cos., Oklahoma.

Notes: Trigenotyla blacki , unlike the preceeding species, shows troglobitic adaptations in its reduced ocelli and pale pigmentation. As such it is presently the only troglobitic milliped known from Oklahoma.

Causey recognized this species as new, and labelled it “reducta,” a name which was never published. Black (1971) lists “two undescribed species” of Trigenotyla from Oklahoma caves, as determined by Causey. However, the present study reveals that actually three species are involved (see below). The Delaware Co. records refer to blacki , those from Seminole Co. to T. seminole , new species, and those from Johnston and Murray Cos. to T. vaga Causey.

Trigneotyla seminole , new species Figs. 16–19

Types: Male holotype, two male paratypes and one female paratype from Whiskey Cave, 9 mi. SE Bowlegs, Seminole Co., Oklahoma, collected 14 January 1974, by J. H. Black (FSCA). The following specimens (all collected in Seminole Co. by J. H. Black; FSCA) are paratypes: Doolin Cave, 8 mi NW of Sasakwa, 14 March 1974, male; Cold Springs Cave, 9 mi SE Bowlegs, 14 January 1974, female.

Diagnosis: Resembles T. vaga Causey in having gonopod ectal coxites broad in lateral view, differs in the shape of those coxites, smaller size and lack of pigmentation.

Etymology: The species name is a noun in apposition, for Seminole County.

Male holotype: Length, 5.0 mm, width 0.75 mm. Unpigmented. Segmental shoulders low; segmental setae (most rubbed off in type series) about equal to body width. Fourteen to 17 round, well­pigmented ocelli in four rows forming triangular eyepatch. Pregonopodal legs enlarged, pair 6 ( Fig. 16 ) the largest.

Gonopods ( Fig. 17 ) with sternal lobes low; coxae not fused in midline; coxal setae not ensiform, in two groups, lateral group of 5 or 6 tightly clustered at distal ectal shoulder of coxa, mesal group of three near gonopod midline. Mesal coxites thin, evenly tapered, curved at tips, posterior edges not serrate; ectal coxites laterally flattened, in lateral view with 3 teeth. Ninth legpair ( Fig. 18 ) typical of genus, but with 2–3 vestigial articles distal to prefemur; coxal glands prominent; legpairs 10, 11 ( Fig. 19 ) with coxal glands, otherwise unmodified.

Female paratype: Length 5.0 mm, width, 0.8 mm. Nonsexual characters as in male.

Distribution: Known only from caves in Seminole Co., Oklahoma. All localites are north of the Canadian River, and it is hypothesized that this barrier separates the present species from the distribution of the closely related T. vaga .

Notes: Trigenotyla seminole populations are unpigmented or very lightly so, but have pigmented, well­formed, and numerous ocelli. Though the species has never been found on the surface, I suspect it is troglophilic, not troglobitic.

Causey had labelled all Oklahoma Trigenotyla (aside from the Delaware Co. collections described above as T. blacki ) as “profunda,” an unpublished name. This judgement is reflected in Black’s (1971) treatment of Oklahoma Trigenotyla . However, Seminole Co. collections north of the Canadian River are clearly distinct from those south of the river in being smaller, less pigmented, and have differences in the gonopods and ninth legs. Thus they are named here as a new species.

Figures

FIGURES 12 – 15. Trigenotyla parca Causey, 12, gonopods, anterior view. Trigenotyla blacki n. sp., 13 – 15. 13, gonopods, anterior view. 14, male ninth legs, anterior view. 15, male right sixth leg, posterior view. Scale lines for Figs. 12 – 14 = 0.1 mm (100 µm), for Fig. 15, 0.5 mm (500 µm).

FIGURES 16 – 19. Trigenotyla seminole, n. sp. 16, male right sixth leg, posterior view. 17, gonopods, anterior view. 18, male ninth legs, posterior view. 19, male right eleventh legpair, anterior view. Scale lines for Figs. 17 and 18 = 0.1 mm (100 µm), for Figs. 16 and 19, 0, 5 mm (500 µm).