Typhloelmis finegan Barr, 2015

Barr, Cheryl B., Gibson, J. Randy & Diaz, Peter H., 2015, TyphloelmisBarr (Coleoptera: Elmidae: Elminae), a New Stygobiontic Riffle Beetle Genus with Three New Species from Texas, USA, The Coleopterists Bulletin 69 (4), pp. 531-558 : 531-558

Typhloelmis finegan Barr , new species ( Figs. 1 , 8 , 12 , 15 , 18 )

Material Examined. HOLOTYPE ♀ in EMEC, labeled “ USA: Texas: Val Verde Co. / Devils River State Natural / Area , Finegan Springs , 405m / 29.9011°,-100.9987°, 25-II- / 2010, J. R. Gibson & P. H. Diaz “ // [genitalia vial] // “ HOLOTYPE Typhloelmis finegan Barr ” [red label, handwritten].

Description. Holotype female. Length 4.1 mm (elytra + pronotum), width 1.2 mm. Cuticle redbrown, barely translucent, with extensive whitish dorsal and ventral plastron; surface smooth, lacking dorsal carinae, striae, and punctures ( Figs. 8 , 12 ). Antenna: Color medium red-brown, antennomeres 1–10 narrowly cone-shaped, wider distally than basally; antennomere 11 narrowly fusiform and acutely pointed ( Figs. 8 , 12 , 15 , 18 ). Head: Color medium red-brown, darker at clypeal margin; surface bearing evenly spaced, small granules and short setae. Eyes absent ( Figs. 12 , 15 , 18 ). Labrum with long, pale setae on distal 1/2. Mandible dark brown with 2 short teeth; upper tooth longest, narrow with blunt tip; lower tooth much shorter and broader. Pronotum: Color dark red-brown, covered with whitish plastron except at anterior margin and antero-medially on disc where abraded ( Fig. 8 ). Longer than wide; length 1.4 mm, width 1.1 mm at widest point just anterior to base ( Figs. 8 , 12 , 15 ). Lateral margins distinctly reflexed; crenulate with small, rounded, evenly spaced teeth; basolateral angles blunt and rounded. Disc with short, sparse setae; small, protuberant granules emergent from plastron adjacent to apicolateral and lateral margins. Elytron: Color dark redbrown, covered with whitish plastron except for at basal margin and suture, and where scratched and abraded medially ( Fig. 8 ). Length 2.7 mm, width 0.6 mm at widest point. Disc with short, sparse setae; widely spaced, small, round granules emergent from plastron, more protuberant laterally; loosely arranged into longitudinal rows more closely spaced laterally. Outer 1/3 of disc in posterior 1/2 wrinkled, with irregular grooves perpendicular to lateral margin. Lateral margin serrate with evenly spaced teeth ( Figs. 8 , 12 ). Leg: Color of coxa, trochanter, femur, and tibia dark red-brown; tarsus medium red-brown. Pro- and mesothoracic legs without plastron, shiny; metathoracic leg with plastron present on coxa, trochanter, and femur, absent on tibia and tarsus. Femur with low granules and fine setae dorsally, flattened and granulate ventrally; pro- and mesofemora with numerous, spinose granules at margins of ventral flattened area; metafemur much less granulate and spinose. Tibia with large granules bearing prominent spines on all surfaces, spines largest, most numerous, at apex ( Fig. 12 ); protibia with spines most well-developed ( Figs. 12 , 15 , 18 ). Tibia of all legs with fringe of long, pale setae (tomentum) on medial surface ( Figs. 8 , 12 ); protibia with tomentum at middle 1/3, meso- and metatibiae with tomentum extending most of length except for at base and apex. Tarsomeres 1–4 with short, stout setae at ventral apex; tarsomere 5 with few setae along length of ventral surface. Claws moderately slender and barely curved. Venter: Color light red-brown, covered with plastron; setae short and sparse. Prosternum ( Fig. 18 ) covered with variably spaced granules; prosternal process narrowly triangular, apex broadly rounded, nearly truncate. Metaventrite ( Fig.12b ) covered with numerous, closely spaced granules; anterior margin truncate between mesocoxae; metakatepisternal suture slightly arcuate, discrimen obvious just anterior to intersection only. Abdominal ventrites ( Fig. 12b ) with widely spaced, low granules and setae; ventrite 1 with granules present on entire surface; ventrites 2–4 with granules present mainly laterad; ventrite 5 with apical 1/2 granulate and setose, with shallow median depression near apex, apex bearing fringe of fine, moderately long setae; intercoxal process of ventrite 1 triangularly shaped, apex acute. Female genitalia: Each longitudinal bacula subequal in length to gonocoxite; stylus short, narrowly ovoid. Median sclerite present between bases of gonocoxites, both dorsally and ventrally. Vagina extruding between the gonocoxites well beyond tips of styli.

Variation. Unknown.

Diagnosis. Typhloelmis finegan ( Fig. 8 ) is unlikely to be confused with either T. caroline ( Fig. 6 ) or T. sanfelipe ( Fig. 7 ) because it is much larger (length> 4 mm vs. <3 mm) and darker colored. In addition, in T. finegan ( Figs. 8 , 12 , 15 , 18 ) the prosternal process is broader, triangular, and not medially constricted; the pronotum is margined with rounded, evenly spaced teeth; antennomeres 1–10 are similarly cone-shaped; the metaventrite is very granulate; the femora are ventrally flattened; the tibia of all legs possesses fringes of tomentum; and protarsomere 5 is not bulbous. In both T. caroline ( Figs. 6 , 9 , 13 , 16 ) and T. sanfelipe ( Figs. 7 , 10 , 14 , 17 ), the prosternal process is narrow and elongate; the pronotal margins have irregular granules or teeth; antennomeres 1–10 are not similarly cone-shaped, and antennomere 2 is larger than all but antennomeres 1 and 11; the metaventrite is sparsely granulate; the femora are not ventrally flattened; a fringe of tomentum is present on the protibiae only; and protarsomere 5 is bulbous.

Etymology. Finegan, a noun in apposition, from the type locality, Finegan Springs.

Habitat. Finegan Springs ( Figs. 1 , 27, 28 ) are located in the Devils River State Natural Area (Texas Parks and Wildlife Department) west of Loma Alta, Texas, in the Edwards Plateau Ecoregion ( Bureau of Economic Geology 2010). At the site, a series of small springs ( Fig. 28 ) emerge from early Cretaceous Edwards Limestone ( Bureau of Economic Geology 1992) at the base of a limestone bluff adjacent to the east bank of the upper Devils River, joining to form a stream that flows over impermeable chert bedrock (B. F. Schwartz, in litt.) before emptying into the river ( Fig. 27 ). Historic discharges from the springs ranged between 99– 760 L/s ( Brune 1981) from five measurements taken in the years 1928–1971. The single specimen of T. finegan was collected from the spring outlet termed “Finegan Spring 1” in Külköyluoğlü et al. (2011).

Associated Fauna. Finegan Springs are the type locality for the spring-endemic ostracod Bicornucandona fineganensis Külköyluoğlü, Gibson, Diaz, and Colin (2011) . Other subterranean aquatic fauna present in the outflow of the springs includes the isopods (Crustacea) C. texensis , Lirceolus sp. , and S. hardeni and the amphipods (Crustacea) A. subterranea , P. americana, Paraholsingerius smaragdinus (Holsinger), P. ruffoi , S. hershleri , and Stygobromus hadenoecus (Holsinger) . Epigean riffle beetles present in the springs include H. glabra , unidentified Microcylloepus , P. clavicornis (Elmidae) and Psephenus Haldeman (almost certainly P. texanus although adults have not been collected) ( Psephenidae ); the population of H. glabra at the springs was included in a population genetics study of Heterelmis by Gonzales (2008). An unidentified species of marsh beetle in the genus Prionocyphon Redtenbacher (Scirtidae) has also been identified from the springs. The spring-associated roundnose minnows D. diaboli and D. argentosa regularly occur in the stretch of the Devils River from Finegan Springs to Dolan Falls 1.5 km downstream.

Figures

Figs. 1–2. 1) Map of Terrell and Val Verde counties, Texas, showing the type localities of Typhoelmis caroline at Caroline Springs, Typhoelmis sanfelipe at San Felipe Springs, and Typhoelmis finegan at Finegan Springs; 2) Map of the Edwards and Trinity Aquifer regions of Texas. GWD = groundwater divide; black dots = type locality springs.

Figs. 6–8. Typhloelmis species, adult dry specimens, dorsal view (length = pronotum + elytra). 6) T. caroline, ♂, length 2.2 mm; 7) T. sanfelipe, ♀, length 2.5 mm; 8) T. finegan, ♀, length 4.1 mm.

Figs. 11–12. Typhloelmis species, adult wet specimens. 11) T. sanfelipe, lateral view; 12) T. finegan, a) Dorsal view, b) Ventral view.

Figs. 13–15. Typhloelmis species, adult wet specimens, anterior dorsal view. 13) T. caroline; 14) T. sanfelipe;

Figs. 16–19. Typhloelmis species, adult wet specimens, ventral view. 16) T. caroline, anterior; 17) T. sanfelipe, anterior; 18) T. finegan, anterior; 19) T. sanfelipe, fused elytra.

Figs. 9–10. Typhloelmis species, adult wet specimens. 9) T. caroline, a) Dorsal view, b) Ventral view; 10) T. sanfelipe, a) Dorsal view, b) Ventral view.

Figs. 27–28. Finegan Springs, type locality of Typhloelmis finegan. 27) Spring run with outflow of small springs entering on left; 28) Spring head with three drift nets.