Speorthus reyesi, Shear & Reddell, 2017

Shear, William A. & Reddell, James M., 2017, Cave millipedes of the United States. XIV. Revalidation of the genus Speorthus Chamberlin, 1952 (Diplopoda, Polydesmida, Macrosternodesmidae), with a description of a new species from Texas and remarks on the families Polydesmidae and Macrosternodesmidae in North America, Insecta Mundi 2017 (529), pp. 1-13 : 3-4

Speorthus reyesi , n. sp.

Fig. 7–14 , 18 , 19 , 21

Types. Male holotype and male and female paratypes from Rattlesnake Cave , Ward Co., Texas, collected 12 May 1986 by J. Reddell, M. Reyes and A. R. Smith ; deposited in the Virginia Museum of Natural History , Martinsville, VA .

Etymology. The new species is named for Marcelino Reyes, in recognition of his many collections of millipedes from west Texas caves, including Rattlesnake Cave.

Diagnosis. Differs from S. tuganbius in details of the male gonopod: in S. reyesi the prefemoral process is broader than in S. tuganbius , and somewhat scoop-shaped (pfp, Fig. 12, 13 ), while the endomerite (e, Fig. 14 ; process near the pulvillus, p) is shorter than that of S. tuganbius . In nonsexual characters, the two species of Speorthus are nearly identical.

Description. Male holotype. Length, 9.6 mm, greatest width 0.9 mm; 19 + t rings. Head subglobular, densely setose. Antennae clavate, sixth antennomere enlarged; when fully extended, antennae reaching midpoint of third trunk segment. Collum ( Fig. 7 ) suboval, without acute posteriolateral corners. Anterior metazonites ( Fig. 7 ) with three rows (including posterior marginal row) of 12–14 small, acute setae arising from distinct pustules; lateral margins of metazonites strongly toothed, with three distinct, posterior-pointing teeth, posteriolateral angle drawn out to at least twice size of more anterior teeth; posteriorly, transition to five rows of setae ( Fig. 8 ), rows becoming progressively more irregular, with five marginal teeth. Ozopores opening from well-developed calluses just anterior to extended posteriolateral corners ( Fig. 8 ). Epiproct ( Fig. 9 ) rounded. Anterior legs with irregularly distributed sphaerotrichomes ventrally ( Fig.10 , 11 ). Gonopods ( Fig. 12–14 , 17, 18 ) set in broad, suboval aperture taking up entire width of seventh prozonite. Gonocoxae subglobular, tightly appressed in midline, not movable with respect to one another, anteriorly deeply excavate to receive telopodites ( Fig. 12 ). Prefemora transverse, in posterior view extending across width of goncoxae ( Fig. 13 ); prefemoral process originating laterally at base of acropodite, broad, scoop-shaped, cupping terminal process of acropodite, endomerite short, acute, sinuate ( Fig. 14 , 17, 18 ). Opening of seminal or prostatic groove large, slotlike, with few fimbriae ( Fig. 14 ).

Female paratype. Length, 9.8 mm, greatest width 1.0 mm. Nonsexual characters as in male.

Distribution. Known only from the type locality, a cave in a small pocket of gypsum karst in Monahans, Ward County, Texas ( Fig. 20 ).

Figures

Figure 21. Southeastern New Mexico and western Texas, showing distribution of Speorthus tuganbius (dots; includes localities reported by Shear [1974]), and the type locality of S. reyesi, new species (square).

Figures 7–10. Speorthus reyesi male. 7) Collum and trunk rings two and three, dorsal view. 8) Ninth ring, dorsal view. 9) Epiproct, dorsal view. 10) Prefemur of left leg nine, ventral view.

Figures 11–14. Speorthus reyesi male. 11) Sphaerotrichome from prefemur of left leg nine, ventral view. 12) Gonopods, anterioventral view, gonopods extended for copulation (posterior above); a, acropodite, cx, coxa, e, endomerite, pf, prefemur, pfp, prefemoral process. 13) Gonopods, posterioventral view, gonopods retracted into anterior coxal cavities (anterior above). 14) Opening of seminal channel and endomerite, ventral view; e, endomerite, p, pore of seminal channel.

Figures 15–18. Speorthus gonopods. 15) Right gonopod of S. tuganbius, mesal view. 16) Same, lateral view. 17) Right gonopod of S. reyesi, mesal view. 18) Same, lateral view. Abbreviations as in Fig. 12.

Figures 19–20. Speorthus tuganbius, photographed in habitat at Carlsbad Caverns National Park, New Mexico. 19) Male. 20) Mating pair. Photographs courtesy of Jean Krejca.