Stenotarsus nigrivestis Shockley, 2007

López-Guerrero, Irma, 2007, Figs. 30 – 33. Attavicinus monstrosus. 30 in Comparison of Mouthpart Morphology of Three Species of Mexican Oniticellini (Coleoptera: Scarabaeidae: Scarabaeinae) in Relation to Their Trophic Habits, The Coleopterists Bulletin 61 (3), pp. 479-486 : 479-486

Stenotarsus nigrivestis Shockley , new species

( Figs. 1–9 )

Etymology. The specific epithet is derived from the combination of the Latin root ‘‘nigri-,’’ meaning ‘‘black’’ + the suffix ‘‘vestis,’’ meaning ‘‘clothing or coat.’’ This refers to the unusual black vestiture covering most of the dorsal surface.

Typology. Holotype (male). ‘‘ DOMIN. REP: Prov. Pedernales; N. of Pedernales, 188 m; La Aguita, 21 JULY 1989; 18 ° 09.172 9 N, 71 ° 44.786 9 W; M.A. Ivie, Guerrero & Dominici. ’’ Holotype from West Indian Beetle Fauna Project Collection ( WIBF), deposited in the NMNH . Paratypes. ‘‘ DOMIN. REP: Prov. Pedernales; N. of Pedernales , 188 m; La Aguita, 21 JULY 1989; 18 ° 09.172 9 N, 71 ° 44.786 9 W; M.A. Ivie, Guerrero & Dominici’’ [7 ex.]. ‘‘ DOMIN- ICAN REP.: Prov. Barahona, nr. Filipinas Larimar Mine : 26-VI-7-VII-1992 : Woodruff & Skelley, day beating’’ [2 ex., 1 male, 1 female]. ‘‘ DOMINICAN REP.: Prov. Barahona, nr. Filipinas Larimar Mine : 20–26-VI-1992 , R. E. Woodruff & P.E. Skelley, at night’’ [1 ex.]. ‘‘DOM.REP: Prov. Hato Mayor ; W. Sabana de la Mar; Par. Nac. Los Haitises; bosque humido, 01 JULY1992; M.A. & R. O. Ivie colrs’’ [3 ex.]. ‘‘DOM.REP: Prov. Hato Mayor ; W. Sabana de la Mar; Par. Nac. Los Haitises; 02 JULY1992- 16 JULY1993; D. Sikes & R. Rosenfield; flight intercept trap’’ [1 ex.]. ‘‘DOM.REP: Prov. Hato Mayor ; W. Sabana de la Mar; Par. Nac. Los Haitises; bosque humido, 16APR1992 ; M.A. Ivie, D. Sikes, &; W. Lanier. ex rotten log’’ [1 ex., male]. Paratypes deposited in the collections listed under Materials and Methods.

Diagnosis. This distinctive species differs from other species of Stenotarsus by the combination of the following characters: black vestiture; antenna dark basally with pale club; antennomeres IX–XI short and broad; elytra with weak, irregular rows of coarse punctures at base; elytra with epipleural fold reaching apex; setose pores around mesocoxa large, nearly 1/3 the diameter of mesocoxa; mesosternum with a line demarking a hemispherical plate; male genitalia twisted, with small subapical tooth.

Description. Length 5.5–6.2 mm; width 3.5–4.0 mm. Body elongate-oval, primarily black with red-brown head and elytral humeri; vestiture black except as noted below ( Fig. 1 )

Head covered with dense golden pubescence dorsally; eyes large, oval, prominent, relatively coarsely faceted, eye width 8–10 facets. Antennal grooves absent; antennae 11-segmented with pale, loose 3-segmented club ( Fig. 2 ); antennomere III 5 1.5 times II in length; IV–VIII stout, not elongate, each only 482 slightly shorter than III; IX–XI forming a weakly asymmetrical club; XI subcircular; antennomeres I & IX–XI with golden pubescence, II–VIII with vestiture primarily black. Fronto-clypeal suture straight. Clypeus transverse, rectangular, and flat.

Pronotum ( Fig. 3 ) with broad, flat lateral margin demarked by a weak groove which continues forward and merges with the anterior marginal groove; lacking a basal sulcus; basal pores (one on each side) each connected to a short, straight groove that extends anteriorly; pronotum with an even covering of fine punctures each bearing a black seta, except at base between the 2 pores where punctures are enlarged and nearly touch each other. Scutellum rounded, nearly hemispherical. Elytron oval, strongly convex; elytral length 5 3.25 times pronotal length; vestiture black except over the red-brown humerus and on extreme apex where vestiture is golden; punctation dense and fine as on pronotum except near base where coarse punctures appear in weakly defined rows ( Fig. 3 ); epipleural fold gradually decreases in width before reaching sharply-margined elytral apex.

Thoracic venter ( Fig. 5 ) covered in a mixture of dark brown and gold vestiture. Prosternum with anterior margin marked by a small complete groove; posterolateral margin incomplete, broken near midpoint into two lines, one running anterior to procoxa and one running along margin between procoxae; procoxa globose; prosternum prolonged behind procoxae and expanded, apically truncate, fitting into a depression on mesosternum. Mesosternum somewhat transverse; bearing a secondary line that encloses a hemispherical plate; with a large setose pore on each side near mesepisternum. Mesocoxa globose. Metasternum evenly covered with fine punctures, with a deeply impressed submarginal groove that runs parallel to anterior margin and anterior portion of lateral margin; two large, impressed, setose pores located posterior to mesocoxa along the submarginal groove, each pore nearly 1/3 diameter of mesocoxa. Metepisternum with submarginal line along medial margin opposite metasternum; bearing a large, impressed, setose pore anteriorly.

Legs ( Fig. 4 ) red-brown with golden vestiture, except for darker bases of the tibia and femur, which also have a darker vestiture; all legs similar in overall appearance; femur widest near midlength; tibia straight and gradually widening apically; tarsi 4-4-4, pseudotrimerous with tarsomeres I–II ventrally lobed, III much reduced; claws simple.

Wing ( Fig. 6 ) with reduced venation in apical region, bearing fringe of stout setae along distal 2/3 of costa. Posterior margin bearing short, fine setae from the claval fold to a point equidistant between cubital fold and the wing apex. MP 1+2 long, sclerotized, connected with partially reduced radius posterior. Medial bridge present. Medial fleck with long narrow portion extending posterodistally to midpoint between wing apex and cubital fold, extension abruptly widened at posterior wing margin. Radial cell reduced. Anal anterior (AA) fused with the cubitus posterior (CuP) and extending as a single vein posterodistally before connecting to incomplete cubitus anterior (CuA) to form a distinct ‘‘hook.’’

Abdomen ( Fig. 7 ) with six freely articulated ventrites; ventrite I black, with scattered coarse punctures; II–V red-brown; length of I 5 length of II–IV combined; II–IV subequal in length. Aedeagus ( Figs. 8, 9 ) stout, comparatively long, relatively narrow, sclerotized, curved and twisted, appearing laterally 484 flattened; tegmen reduced; median lobe with apex sharply pointed and bearing a subapical tooth.

Biology/Ecology. According to field notes provided by M.A. Ivie (in litt.), specimens from the type series were collected near a small stream along the border road north of Pedernales at a water-gathering spot between Rio Banana and Aguas Negra. This is a disturbed mesic forest on a limestone base. Larvae and adults were intermixed and exposed on the surface of a fungus mostly on the underside of a dead log, though some were taken from the upper surface of the log as well. The 16 April 1992, 01 July 1992 and 16 July 1993 FIT specimens are all from the same site, a mesic sea-level forest in the karst formations of Los Haitises National Park. The area is mostly secondary forest with large regrowth of trees in and around old Cacao, citris and banana plots. The specimens were on a fungus on a large dead log and were running around exposed on the surface. The specimens collected by Woodruff and Skelley in Prov. Barahona were collected just above the lower edge of the cloud forest line in the mountains inland from the small coastal town of El Arroyo. The site was primarily old overgrown coffee fields that had natural woodlands nearby (P.E. Skelley, in litt.). The similar conditions under which all examined specimens were collected, in pre-montane to montane secondary forest, suggests that S. nigrivestis may prefer these conditions though examination of additional material is needed to confirm this.

In addition, larvae were collected on two separate occasions: DOM. REP. Prov. Pedernales; N. of Pedernales; La Aguita 620 9; 18 ° 09.172 9 N, 071 ° 44.786 9 W; 21 JULY 1999; endomychids on fungus & log; Ivie, Guerrero & G. Dominici (40+ larvae). DOM. REP. Prov. Barahona; 18 km from Cabral off Polo Rd. ; 25 km SE Montear Nuevo; 18 ° 06.452 9 N, 71 ° 14.717 9 W; 3370 9 26 JULY 1999; M.A. Ivie & K.A. Guerrero; coffee-Magnolia forest (1 larva). These larvae are in the process of being described with other endomychid larvae in a separate manuscript .

Sexual dimorphism, fairly common albeit inconsistent among Stenotarsus species (Roubik and Skelley 2001), does not appear to be present in S. nigrivestis . Based on the limited number of specimens available for study, there does not appear to be any secondary sexual features useful for separating sexes.

Figures

Fig. 1. Stenotarsus nigrivestis Shockley, n. sp., holotype. Scale bar: 1.0 mm.

Figs. 2–5. Stenotarsus nigrivestis Shockley n. sp. 2) antenna; 3) prothorax and elytral base, dorsal view; 4) left mesothoracic leg; 5) pro-, meso-, and metasternum, ventral view (legs removed). Scale bars: 1.0 mm.

Fig. 6. Stenotarsus nigrivestis Shockley n. sp., wing. Scale bar: 1.0 mm.

Figs. 7–9. Stenotarsus nigrivestis Shockley n. sp. 7) abdomen, ventral view; 8) aedeagus, lateral view; 9) aedeagus, ventral view. Scale bars: 1.0 mm.