Trichotichnus (Iridessus) autumnalis

Kataev, B. M., 2020, Description of a new subgenus of Trichotichnus (Coleoptera: Carabidae), with two new species from the Western Ghats (India), and remarks on other subgenera, Zoosystematica Rossica (China) 29 (2), pp. 172-194 : 187-188

Trichotichnus (Iridessus) autumnalis

( Say, 1823)

(Figs 24–28)

Feronia autumnalis Say, 1823: 48 .

Episcopellus nitescens Casey, 1914: 236 .

Material examined. Canada, Ontario : 1 female, Ontario, Lake Erie, Long Point , 7.VI.1956, K. Lindroth leg. ( ZIN) ; 1 male, Lake Erie, Point Pelee , 13–14.VI.1956, K. Lindroth leg. ( ZIN) . USA: 2 males, 1 female, Missouri, Callaway County, Mark Twain National Forest , 18 km SWW Fulton, 38°48.0ʹN 92°08.3ʹW, 200 m, in forest litter, 14.V.2003, V. Gusarov leg. “[1821]” ( ZIN) ; 1 male, Illinois, Union County, Shawnee “S. F.”, Pine Hill , 31.IV.–1.V.1979, H. Goulet leg. ( ZIN) ; 1 female, Maryland, Chevy Chase , 24.VII.1946, E. Suenson leg. ( ZIN) ; 1 male, Indiana, Dunes State Park , Porter County, 8.VI.1988, N.M. Downie leg. ( FMNH) .

Diagnosis. Among members of Iridessus , this species is recognised by elongate body, impunctate pronotum and comparatively wide genae. In impunctate pronotum and wide genae, it is similar to T. nitidulus , but can be easily distinguished by narrower body, more distinct fronto-ocular furrows and by presence of parascutellar setigerous pore on elytra.

Description. Body length 6.5–7.8 mm, width 2.3–3.4 mm. Dark piceous to black, with very narrow margins of pronotum and elytra as well as elytral suture reddish brown; palpi, antennae and legs brownish yellow. Fronto-clypeal suture and fronto-ocular furrows very shallow, fine. Genae moderately wide, about as wide as antennomere 2. Left mandible acute at tip. Mentum (Fig. 24) separated from submentum by complete suture; ligular sclerite almost parallel-sided, very slightly narrowed before apex; paraglossa rather wide, separated from ligular sclerite by narrow notch. Pronotum impunctate, with basal angles distinct, angulate. Elytra with lateral groove narrow and flat throughout, without elongate convexity along this groove apically. Elytral marginal umbilicate series with a short gap medially, consisting of seven to nine setigerous pores in anterior group and of eight and nine such pores in posterior group. Metepisternum markedly longer than wide. Profemur anteriorly with at least four setigerous pores along entire length of lower margin. Metafemur ventrally with two setigerous pores at posterior margin. Tarsi dorsally glabrous. Mesotarsomere 1 of male elongate, approximately as long as mesotarsomeres 2 and 3 combined, with a pair of very small adhesive scales just at apex. Abdominal sternite VII with two pairs of marginal setae in both sexes. Gonocoxite (Figs 25, 26) basally with one short stout seta on ventral outer edge and one thin seta on dorsal outer edge. Median lobe of aedeagus (Figs 27, 28) with apical orifice shifted to left and with apical capitulum prominent both dorsally and ventrally. Internal sac with a short spine in apical portion.

Distribution. Eastern Canada and the eastern United States, south at least to northeastern Kansas, central Arkansas, southwestern Mississippi, northern Georgia, and eastern South Carolina ( Bousquet, 2012).

Remarks. The systematic position of this species was changed many times soon after the description. In more recent time, Casey (1914) erect- ed for it the genus Episcopellus within Acupalpini (= Stenolophina ). Lindroth (1968) also considered Episcopellus as a separate genus but close to Harpalus , whereas Ball (1960), Habu (1973) and Noonan (1985) treated it as a synonym of Trichotichnus . Finally, Kataev (in Ball & Bousquet, 2000) included T. autumnalis in the subgenus Iridessus . The morphological characteristics of this species listed above, rather well agree with the diagnosis of this subgenus.