Stenotarsus thoracicus Gorham

Arriaga-Varela, Emmanuel, Zaragoza-Caballero, Santiago, Tomaszewska, Wioletta & Navarrete-Heredia, Jose Luis, 2013, Preliminary review of the genus Stenotarsus Perty (Coleoptera: Endomychidae) from México, Guatemala and Belize, with descriptions of twelve new species, Zootaxa 3645 (1), pp. 1-79 : 48-49

Stenotarsus thoracicus Gorham

( Figs. 42 , 47 , 78 , 114 , 133 , 183 , 243 –244, 256, 265 )

Stenotarsus thoracicus Gorham, 1890: 136 ; Blackwelder 1945: 440; Strohecker 1953: 57; Arriaga-Varela et al. 2007: 16; Shockley et al. 2009a: 85.

Diagnosis. This species resembles S. globosus and S. rubrocinctus due to its contrastly colored, rather short oval body ( Fig. 42 ), pronotum with oblique and reniform basal foveae ( Fig. 114 ), and abdominal ventrite V scarcely longer than IV. Stenotarsus thoracicus can be distinguished from these by the shape of the median lobe, which is slightly stouter and narrowing apically, in ventral view ( Fig. 243 ), the male metaventrite lacking a concavity near the anterior margin between mesocoxae, and male metafemur and metatibia unarmed ( Fig. 183 ). Females could be hard to distinguish from those of S. globosus and S. rubrocinctus . The main differences that distinguish them are: body slightly shorter (1.6X as long as wide), pronotum with smaller basal pores ( Figs. 92 , 107, 114 ), slightly wider prosternal process ( Figs. 127, 133 ), and shorter legs.

Description of males. Body 5.20–5.65 mm long, short oval, markedly convex ( Fig. 42 ), 1.54–1.60X as long as wide, 2.50–2.65X as long as high. Contrastly colored with head orange-red, antenna uniformly black or with antennomeres 1–7 red or gradually infuscate; pronotum with a large semicircular to subtriangular black macula; hypomeron and prosternum orange red; scutellum orange-red to slightly infuscate; elytra red, each elytron with large, oval, black macula; epipleura red; mesosternum orange red; mesepisternum, mesepimeron, metasternum and metepisternum black, legs orange red to black; abdomen orange-red with base of first ventrite black ( Fig. 47 ). Densely covered with long, suberect, golden setae, with black setae in the black parts of elytra and pronotum.

Head: Clypeus transverse, 2.0–2.2X wider than long. Terminal labial palpomere narrow, acuminate, narrowly truncate apically. Interocular distance 0.63–0.65X as wide as head. Antenna rather long and slender ( Fig. 78 ), 0.45– 0.50X as long as body; scape 1.5X as long as wide, 1.6X longer than pedicel; pedicel 1.3X longer than wide; third antennomere 1.4X as long as wide, 1.2X as long as pedicel; fourth 1.6X as long as wide, 1.4X as long as pedicel; fifth 1.7X as long as wide, 1.5X as long as pedicel; sixth and seventh subequal to fifth; eighth 1.4X as long as wide, 1.4X longer than pedicel; antennal club 0.4X as long as total antennal length, with segments almost symmetrical; ninth antennomere widened apically, 1X as long as wide, 1.9X as long as pedicel; tenth widened apically, as long as wide, 2X as long as pedicel; terminal antennomere oblong, widest near middle, 1.5X as long as wide, 3.4X as long as pedicel.

Prothorax: Pronotum widest at base, strongly transverse ( Fig. 114 ), 2.3–2.4X wider than long, 2.0–2.1X wider at base than at front angles, 2.25–2.35X wider than head. Sides almost gradually rounded, less convergent in basal half. Front angles moderately produced, right-angled, briefly blunt at tip. Hind angles right-angled. Anterior margin narrow, slightly arcuate medially. Lateral margins raisedmarkedly wide, narrowing posteriorly: width of margin at base 1/3 of the distance between basal pore and hind angle; area between marginal line and pronotal edge flat. Disc moderately convex, finely and closely punctate. Longitudinal sulci slightly impressed, short, narrow and weakly curved. Basal pores small, slightly curved, markedly oblique. Basal sulcus complete, almost lacking near scutellum. Pronotal base lobed medially. Prosternal process wide at base, widened posteriorly; as wide as longitudinal procoxal diameter apically ( Fig. 133 ).

Pterothorax: Scutellum triangular, moderately large, 1.6–1.8X wider than long, 0.15X as wide as pronotum. Elytra 3.4–4.0 mm long, 1.0–1.1X longer than wide, 3.6–3.7X longer and 1.41–1.5 2X wider than pronotum; markedly ovoid, widest at basal third, then roundly convergent to the moderately acuminate apex. Moderately densely punctate with foveolate punctures small and somewhat deep, separated by 2–5 diameters, sparser and shallower apically and near scutellum. Humerus moderately prominent. Epipleuron moderately wide at base, 0.8– 0.9X as wide as the intercoxal process of metaventrite. Mesoventrite deeply excavated in front; bearing small setose pores laterally; mesoventral process scarcely wider than longitudinal coxal diameter, without medial carinae. Metaventrite moderately convex, without modifications on anterior margin; with pair of small setose pores of approximately same diameter posterior to each mesocoxa. Metepisternum with small setose pore.

Legs: moderately long and slender ( Fig. 183 ). Trochanters simple. Meso- and metafemora moderately widened at midlength, unarmed; metafemur as long as mesofemur, bearing moderately long decumbent setae. Meso- and metatibiae moderately slender; metatibia as long as metafemur, 0.31–0.34X as long as elytra, gradually widened distally, linear, unarmed. Metatarsus 0.56–0.60X as long as metatibia; second tarsomere produced and lobed, 3X as wide apically as fourth tarsomere at midlength.

Abdomen: ventrite I slightly shorter than metaventrite and that ventrites II–V combined, with moderately coarse foveolate punctation, without protuberances. Ventrite V scarcely longer than IV, with apex truncate; ventrite VI rounded apically. Tergite VIII truncate. Median lobe slender, curved, weakly widened at apical third, then narrowing apically with a small apical crest, in ventral view ( Fig. 244 ); widened near apical third then distinctly narrowed, in lateral view ( Fig. 243 ). Tegmen with moderately large submembranous tegminal plate.

Description of females. Body 4.35–4.40 mm long, 1.6X as long as wide,2.65–2.70X as long as high. Antenna 0.44X as long as body. Pronotum 2.2X wider than long, 1.79–1.82X wider at base than at front angles, 2.12X wider than head. Elytra 2.85–2.89 mm long, 1.03–1.05X longer than wide, 3.2X longer and 1.38–1.39X wider than pronotum. Metatibia 0.30X longer than elytra. Metatarsus 0.58X as long as metatibia. Ovipositor with proctiger rounded, coxites moderately wide, without styli ( Fig. 256 ).

Sexual dimorphism. Females have proportionally shorter antennae and longer elytra.

Variation. Darker specimens have antennae and pronotum completely black.

Material examined. Types. Lectotype (present designation) (male): Syntype [round, blue bordered label] / Type H. T. [round, red bordered label] / Tuxpam, Mexico, Salle coll. / 2196 / B.C.A., VII, Stenotarsus [p] thoracicus Gorh. [h] / Stenotarus thoracicus Guer, Apud Sallé / Stenotarsus thoracicus Guer (type) Tuxpam (NHM). Paralectotype of Stenotarsus tarsalis Gorham (male): Syntype [round, blue bordered label] / Type / Type [round, red bordered label] / Jalapa, Mexico, Hoege / S. tarsalis Gorham [h]/ B.C.A., VII, Stenotarsus [p] tarsalis Gorh. [h] / (NHM). Paralectotype of Stenotarsus tarsalis Gorham (See remarks under description of S. globosus Guérin –Méneville) (female): Syntype [round, blue bordered label] / Jalapa, Mexico, Hoëge / B.C.A., VII, Stenotarsus [p] tarsalis Gorh. [h] (NHM).

Other material. México: Hidalgo, carr. a Chapulhuacán, delante de Palomas, 1499m., bosque mesófilo de montaña pert., N 21o5’28.1’’ W 99º1’15.2’’, troncos podridos, I-VII-2003, J. Asiain, J. Canales y J. Márquez (2 males: UAEH); Tlapacoyan, Ver., 18-IV- 1946, 800m, C. Bolívar (2 males: ENCB); Stenotarsus thoracicus Gorham , det. H.F. Strohecker (1 male: MNB); J / Mexico, coll. J. Flohr (1 female: MNB); Cerr [h] / Mexico, coll. J. Flohr / smithi Gor / Stenotarsus thoracicus Gorham , det. H.F. Strohecker (1 female: MNB); Jalapa 6 / Mexico, coll. J. Flohr / Stenotarsus tarsalis (1 female: MNB).

Distribution. MEXICO: Hidalgo, Veracruz ( Fig. 265 ).

Biological Notes. Altitudinal range: 1–1499 m. Habitat: cloud forest. Period of activity: April and July. Habit: rotten logs.

Remarks. Two members of the type series of S. tarsalis , a male and a female, on which Gorham (1890) based his description (here synonymized under S. globosus Guérin-Méneville ) belong to S. thoracicus .

Figures

FIGURES 38 – 42. Habitus in dorsal view of Stenotarsus spp. Scale bar = 1 mm .. 38) S. sallaei; 39) S. shockleyi; 40) S. smithi; 41) S. spiropenis: 42) S. thoracicus.

FIGURES 43 – 49. 43 – 47. Habitus in ventral view of Stenotarsus spp. 48 – 49 Habitus in lateral view of Stenotarsus spp. 43) S. guatemalae; 44) S. kafkai; 45) S. nigricans; 46) S. militaris; 47) S. thoracicus; 48) S. incisus; 49) S. oblongulus.

FIGURES 72 – 78. Right antennae of Stenotarsus spp. 72) S. raramuri; 73) S. rulfoi; 74) S. sallaei; 75) S. shockleyi; 76) S. smithi; 77) S. spiropenis; 78) S. thoracicus.

FIGURES 105 – 114. Pronotum of Stenotarsus spp. 105) S. ovalis; 106) S. parallelicornis; 107) S. raramuri; 108) S. rubrocinctus; 109). S. rulfoi; 110) S. sallaei; 111) S. shockleyi; 112) S. smithi; 113) S. spiropenis; 114) S. thoracicus.

FIGURES 126 – 143. Thoracic structures of Stenotarsus spp. 126 – 133. Prosternal process. 134 – 136. Scutellum. 137 – 138. Mesoventrite. 139 – 140. Metepisternum. 141 – 143. Anterolateral part of metaventrite. 126) S. cortesi; 127) S. globosus, S. rubrocinctus; 128) S. meosamericanus; 129) S. oblongulus; 130) S. ovalis; 131) S. shockleyi; 132) S. spiropenis; 133) S. thoracicus; 134) S. globosus; 135) S. ovalis; 136) S. spiropenis; 137) S. nigricans; 138) S. spiropenis; 139) S. ovalis; 140) S. spiropenis; 141) S. marginalis; 142) S. nigricans; 143) S. spiropenis. PC. Procoxal cavity. PR. Procoxal rest. SP. Setose pore. MC. Mesocoxal cavity.

FIGURES 174 – 185. 174 – 183. Hind legs of male Stenotarsus spp. 184 – 185. Hind legs of female Stenotarsus spp. 174) S. ovalis; 175) S. parallelicornis; 176) S. raramuri; 177) S. rubrocinctus; 178) S. rulfoi; 179) S. sallaei; 180) S. shockleyi; 181) S. smithi; 182) S. spiropenis; 183) S. thoracicus; 184) S. exiguus; 185) S. globosus.

FIGURES 224 – 243. Lateral and ventral view of median lobe of edeagus of Stenotarsus spp. 224 – 225) S. monterrosoi; 226 – 227) S. nigricans; 228 – 229) S. oblongulus; 230 – 231) S. ovalis; 232 – 233) S. parallelicornis; 234 – 235) S. rulfoi; 236 – 237) S. sallaei; 238 – 239) S. smithi; 240 – 241) S. spiropenis; 242 – 243) S. thoracicus.

FIGURES 244 – 256. Female genitalia structures of Stenotarsus spp. 244) Ovipositor with spermatheca and accessory gland of S. spiropenis, dorsal. 245 – 256. terminal part of ovipositor, dorsal. 245) S. cortesi; 246) S. exiguus; 247) S. globosus, S. raramuri, S. rubrocinctus, S. shockleyi; 248) S. incisus; 249) S. latipes; 250) S. mesoamericanus; 251) S. mexicanus; 252) S. monterrosoi; 253. S. nigricans. 254. S. ovalis. 255. S. sallaei. 256. S. thoracicus.

FIGURES 263 – 265. Distributional maps of Stenotarsus spp. 263) S. lemniscatus (C), S. monterrosoi (S); 264) S. militaris (C), S. smithi (S); 265) S. ovalis (C), S. molgorae (S), S. thoracicus (T). Yellow circles (C), red squares (S), blue triangles (T).

FIGURES 90 – 104. Pronotum of Stenotarsus spp. 90) S. cortesi; 91) S. exiguus; 92) S. globosus; 93) S. guatemalae; 94) S. incisus; 95) S. kafkai; 96) S. latipes, S. molgorae; 97) S. lemniscatus; 98) S. marginalis; 99) S. mesoamericanus; 100) S. mexicanus; 101) S. militaris; 102) S. monterrosoi; 103) S. nigricans; 104) S. oblongulus.