Stenotarsus parallelicornis, Arriaga-Varela, Emmanuel, Zaragoza-Caballero, Santiago, Tomaszewska, Wioletta & Navarrete-Heredia, Jose Luis, 2013

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 : 37-38

Stenotarsus parallelicornis sp. nov.

( Figs. 34 , 71 , 106 , 175 , 232 –233, 257 )

Diagnosis. This species is most similar to S. cortesi sp. nov. and S. mesoamericanus sp. nov. in antennal structure, with antennomeres 3–7 as long as wide, and club slightly longer than the rest of antenna, with its antennomeres elongate and scarcely widened apically ( Figs. 54, 63 ; 71). However, S. parallelicornis can be separated from these species by its uniformly reddish brown body ( Fig. 34 ), lateral margins of pronotum with a small tooth at midlength ( Fig. 106 ), and median lobe widened preapically, in lateral view ( Fig. 232 ).

Description of males. Body 5.5 mm long, short oval, markedly convex ( Fig. 34 ), 1.6X as long as wide, 2.6X as long as high. Uniformly reddish brown except antennal club which is black, eighth antennomere infuscate. Densely covered with comparatively long, suberect, coppery setae.

Head: Clypeus transverse, 2X wider than long. Terminal labial palpomere narrow, acuminate, narrowly truncate apically. Interocular distance 0.7X as wide as head. Antenna moderately long and markedly stout ( Fig. 71 ), 0.45X as long as body; scape 1.2X as long as wide, 2X longer than pedicel; pedicel 0.6X longer than wide; antennomere 3 as long as wide, 1.1X as long as pedicel; fourth and fifth subequal to third; sixth as long as wide, 1.4X as long as pedicel; seventh 0.8X as long as wide, 1.3X as long as pedicel; eighth 0.7X as long as wide, 1.2X longer than pedicel; antennal club 0.58X as long as total antennal length; its antennomeres almost symmetrical and hardly widened apically; ninth antennomere 1.4X as long as wide, 3.3X as long as pedicel; tenth 1.6X as long as wide, 4.1X as long as pedicel; terminal antennomere elongate, nearly parallel sided, 2.6X as long as wide, 7.1X as long as pedicel.

Prothorax: Pronotum widest at base, transverse ( Fig. 106 ), 2.12X wider than long, 2.1X wider at base than at front angles, 2.27X wider than head. Sides convergent in basal half then weakly rounded to front angles, with small tooth at midlength. Front angles produced, right-angled, weakly rounded at tip. Hind angles right-angled. Anterior margin narrow, scarcely arcuate medially. Lateral margins markedly raised and wide, narrowing near base; width of margin at base1/3 of the distance between basal pore and hind angle; area between marginal line and pronotal edge flat to slightly concave. Disc moderately convex, finely and closely punctate. Longitudinal sulci moderately deep, short, curved. Basal pores moderately large, elongated and oblique. Basal sulcus impressed only near pores. Pronotal base nearly straight near scutellum. Prosternal process narrow at base, widened posteriorly; markedly narrower than longitudinal procoxal diameter apically.

Pterothorax: Scutellum triangular, small, 1.2X wider than long, 0.11X as wide as pronotum. Elytra 3.8 mm long, 1.1X longer than wide, 3.55X longer and 1.5X wider than pronotum; ovoid, widest near basal third, then roundly converging to the slightly acuminate apex; moderately densely punctate with foveolate punctures moderately large and comparatively deep, separated by 2–3 diameters, coarser near humeri and slightly sparser and shallower apically. Humerus moderately prominent. Epipleuron at base 0.7X as wide as intercoxal process of metaventrite. Mesoventrite deeply excavated in front; bearing small setose pores laterally; mesoventral process slightly as wide as the longitudinal coxal diameter, without medial carinae. Metaventrite markedly convex, without modifications near the 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 rather stout ( Fig. 175 ). Trochanters simple. Meso- and metafemora moderately slender, widest at midlength, unarmed; metafemur slightly longer than mesofemur, bearing moderately long decumbent setae. Meso- and metatibiae moderately stout; metatibiaas long as metafemur, 0.33X as long as than elytra; widened apically, linear, unarmed. Metatarsus 0.66X as long as metatibia; second tarsomere produced and narrow, 1.2X wider apically than fourth tarsomere at midlength.

Abdomen: ventrite I slightly longer than metaventrite and as long as ventrites II–V combined, with moderately large foveolate punctation posterior to metacoxae, without protuberances. Ventrite V almost twice as long as IV, with apex truncate. Ventrite VI rounded apically. Tergite VIII truncate. Median lobe moderately large and stout, curved, weakly widened towards apex, in lateral and ventral views ( Figs. 232–233 ). Tegmen with moderately large submembranous tegminal plate.

Description of female. Body 6.0 mm long, 1.7X as long as wide, 2.3X as long as high. Antenna 0.41X as long as body. Pronotum 2.25X wider than long, 2.25X wider at base than at front angles, 2.4X wider than head. Elytra 4.15 mm long, 1.18X longer than wide, 3.7X longer and 1.4X wider than pronotum. Metatibia 0.3X as long as elytra. Metatarsus 0.55X as long as metatibia. Ovipositor with proctiger distinctly acuminate, narrowly rounded apically, coxites markedly narrow, without styli.

Sexual dimorphism. The tooth on the lateral margin of the pronotum is smaller in the female.

Material examined. Types. Holotype (male): Motzorongo / Stenotarsus prope . validicornis, H.F. Strohecker det. (MNB); Paratype (female): same data as holotype: (MNB).

Distribution. MEXICO: Veracruz ( Fig. 257 ).

Etymology. The specific epithet refers to the parallel sided articles of antennal club.

Remarks. Gorham (1890) reported the presence of the South American species Stenotarsus claviger Gerstaecker in México and Panamá. Subsequently, Arrow (1920) stated that the specimens studied by Gorham agreed more with S. validicornis Gerstaecker than with S. claviger . Although none of these species were cited from México in the checklists of Blackwelder (1945) and Strohecker (1953), Roubik & Skelley (2001) and Arriaga- Varela et al. (2007) both followed this arrangement for Panamanian and Mexican beetles, respectively.

The specimens described here were labeled by H. F. Strohecker as probably belonging to S. validicornis Gerstaecker. These specimens were compared by us with the type series of S. claviger Gerstaecker , but we were not able to study the type of S. validicornis or the specimens reported by Gorham (1890) because it could not be found. However, it seems highly unlikely that S. validicornis , described from French Guiana, occurs in México.

Figures

FIGURES 26 – 37. Habitus in dorsal view of Stenotarsus spp. Scale bar = 1 mm. 26 – 27) S. militaris; 28) S. molgorae; 29) S. monterrosoi; 30) S. nigricans; 31 – 32) S. oblongulus; 33) S. ovalis; 34) S. parallelicornis; 35) S. raramurii: 36) S. rubrocinctus; 37) S. rulfoi.

FIGURES 54 – 71. Right antennae of Stenotarsus spp. 54) S. cortesi; 55) S. exiguus; 56) S. globosus, S. rubrocinctus; 57) S. guatemalae; 58) S. incisus; 59) S. kafkai; 60) S. latipes; 61) S. lemniscatus; 62) S. marginalis; 63) S. mesoamericanus; 64) S. mexicanus; 65) S. militaris; 66) S. molgorae; 67) S. monterrosoi; 68) S. nigricans; 69) S. oblongulus; 70) S. ovalis; 71) S. parallelicornis.

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 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 257 – 259. Distributional maps of Stenotarsus spp. 257) S. cortesi (C), S. mesoamericanus (S), S. parallelicornis (T); 258) S. exiguus (C), S. incisus (S); 259) S. globosus (C), S. rubrocinctus (S), S. raramuri. (T). Yellow circles (C), red squares (S), blue triangles.