Disciferella, Kataev & Muilwijk, 2020

Kataev, Boris M. & Muilwijk, Jan, 2020, A remarkable new lebiine genus with two new species from Pakistan, Afghanistan and Iran (Coleoptera: Carabidae: Lebiini), Zootaxa 4763 (1), pp. 73-84 : 74-75

Disciferella gen. n.

urn:lsid:zoobank.org:act:07580209-929F-4C1B-B63A-2AC864923E7B

Type species: Disciferella kabakovi sp. n.

Diagnosis. Recognizable by the combination of the following distinctive characters: size rather small (body length 4.4–5.2 mm); body, including eyes, covered with very fine, short and rather dense inclined setae (hairs); head with moderately deep neck constriction and without suborbital setae; mandibles elongate; mentum and submentum completely fused; ligular sclerite with two ventroapical setae; apical palpomeres not widened apically; antennae densely pubescent from antennomere 4, with sparser setae on antennomere 3 and with a few fine setae on two basal antennomeres; pronotal base projecting distally of basal angles; pronotal sides each with a long seta at apex of basal angle and with a short seta at apical angle, with or without anterior lateral seta; proepipleura (prohypomera) basally visible from above; elytra very wide, discoidal, with apices truncate and with striae strongly obliterate, not evident; epipleura of elytra incomplete, not reaching apical angle and not visible from above; abdominal sternites (ventrites) and metasternum normal (three basal abdominal sternites not fused, metasternum not shortened, and metepisternum much longer than wide); protibia without spines along outer margin and with only anterior spur apically (posterior spur absent); apical spurs of meso- and metatibia not longer than half of tarsomere 1; tarsi dorsally setose, slen- der; tarsomere 4 not bilobe; tarsal claws smooth; male protarsomeres 1–4 slightly dilated and covered with sparse spongy adhesive vestiture; gonosubcoxite without spines, and gonocoxite short and wide, glabrous.

Etymology. The generic name is a feminine Latin compound noun based on the words discus (disk or disc) and fĕro (to bring, to bear), plus the diminutive suffix -ella, and referring to the small body size and the discoidal shape of the elytra of the new genus.

Composition. This new genus includes two new allopatric species described in the present paper.

Comparative remarks. The following characteristics of the new genus suggest that it belongs to the tribe Lebiini : 1) antennae densely pubescent from antennomere 4; 2) head not pedunculate posteriorly; 3) protibia without spines along outer margin; 4) meso- and metatibial apical spurs short; and 5) gonosubcoxite lacking spines and setae. Within this tribe, Disciferella gen. n. should be treated as a member of Dromiusina sensu Bouchard et al., 2011 (including Singilina Jeannel 1949, Lionychina Jeannel 1948, and Metadromiina Basilewsky, 1984) since it possesses the following distinctive characters of this subtribe (e. g. Habu, 1967, 1983): 1) head ventrally without suborbital setae; 2) three basal abdominal sternites normal, not fused; 3) tarsomere 4 not bilobe; and 4) gonocoxite not slender nor tapering. Based on the mentum and submentum completely fused, the new genus should formally be included in the Dromius genus-group sensu Ball & Bousquet (2000) (= Dromiusina in narrow sense; = Dromiini sensu Basilewsky, 1984). Additional characteristics of this group, which are also present in the new genus, are: 1) mandibles not widened and not arcuately curved basally, with narrow scrobe; 2) apical palpomeres not widened apically, fusiform; 3) epipleura incomplete, not reaching apical angle and not visible from above; and 4) tarsi slender. However, the very characteristic body shape and the peculiar set of the other morphological character states make it difficult to specify the position of this genus and indicate its closely related genera. Within Dromiusina , it is distinctly recognized already by the very wide, discoidal elytra lacking striae and with widely explanate margins. The peculiar set of its distinctive features also includes: 1) dorsal and ventral surfaces of body covered with very fine, short setae; 2) labium with acute median tooth and with two ventroapical setae on ligular sclerite; 3) three basal antennomeres with sparse setation; 4) pronotum with a short seta at apical angle; 5) proepipleura basally visible in dorsal view; 6) tarsal claws smooth; and 7) male protarsomeres 1–4 slightly dilated and covered with ventral adhesive vestiture. In body pubescence, Disciferella gen. n. is similar to the enigmatic monotypic dromiusine genus Brachynopterus Bedel, 1898 , described from one female specimen collected in Algeria, and known to us only from the rather brief original and subsequent additional, also very brief, descriptions, probably of the same specimen ( Bedel, 1905; Jedlička, 1941; Basilewsky, 1984), and from two photographs (in dorsal view) of the holotype of B. rufulus Bedel, 1898 . Although Brachynopterus is treated by all authors as a member of Dromiusina , its systematic position within this subtribe is obscure. Like the new genus, Brachynopterus has a seta in apical pronotal angle, elytra not striate, tarsal claws smooth and antennomeres with a narrow glabrous strip on outer margin, but it is distinctly differing at least in having pronotum markedly narrowed behind basal angles, proepipleura basally not visible in dorsal view, elytra much narrower, more coarsely punctate and more narrowly explanate along sides, and gonocoxite elongate, slightly arcuate and narrowed apically. By the latter character, Brachynopterus markedly differs from other Dromiusina ( Basilewsky, 1984) . It is also worthy of note that according to the habitus drawing of B. rufulus included in the original description of this taxon ( Bedel, 1898: 241), its mandibles are more rounded at sides than those in the new genus. Unfortunately, there is no available information about the characters visible from ventral side (structure of the labium, presence or absence of the suborbital setae, abdominal sternites, etc).

The new genus also somewhat reminds the monotypic genus Pseudotrechus Rosenhauer, 1856 from southern Spain, Morocco and Algeria, which also has wide, discoidal elytra without striae and with very fine and short, scattered setae on disc. Some authors (e. g. Ball & Bousquet, 2000) include this genus in Dromiusina , but it is distinguished from members of this subtribe by many peculiar characters, which are also absent in Disciferella gen. n., among them the metasternum very short, the metepisternum wider than long and three basal abdominal sternites fused; for this reason Pseudotrechus is usually treated as a member of the monotypic subtribe Pseudotrechina Basilewsky, 1984 (e. g. Basilewsky, 1984; Lorenz, 2005; Bouchard et al., 2011; Kabak, 2017). Pseudotrechus also differs from the new genus in many other sufficient characters including head without neck constriction, mandibles short, arcuately curved, pronotum very wide, with very prominent acute apical angles lacking seta, protibia with posterior spur, tarsal claws basally with two small denticles, etc.

In discoidal elytra, Disciferella gen. n. is also somewhat similar to the South Palaearctic genus Discoptera Semenov, 1889 and to some species of the predominantly African genus Graphipterus Latreille, 1802 , for example, the species of the G. serrator (Forsskål, 1775) group, but these two genera belong to the tribes Cyclosomini Laporte, 1834 and Graphipterini Latreille, 1802, respectively. Both tribes differ from the new genus in numerous characters, including the longer meso- and metatibial apical spurs (distinctly longer than half of the tarsomere 1) and the presence of the strong spines on the outer margin of the protibia. In these two characters, Cyclosomini and Graphipterini markedly differ from all Lebiini including Dromiusina . Although meso- and metatibial spurs in Dromiusina are variable in length, they are at most half as long as the tarsomere 1. In the new genus, the meso- and metatibial spurs are not longer than those, for example, in Lionychus Wissmann, 1846 and Apristus Chaudoir, 1846 .