Anisochirus Jeannel, 1946

Kataev, Boris M., 2021, On some Afrotropical Harpalus, with description of two new species, and remarks on Hypharpax australis (Coleoptera: Carabidae): misidentification, mislabeling and introduction to the Australian region, Zootaxa 5020 (1), pp. 31-56 : 50-52

The genus Anisochirus Jeannel, 1946 , stat. resurr.

Anisochirus Jeannel, 1946: 157 , 158 [as genus]. Type species: Anisochirus alluaudi Jeannel, 1946 (= Harpalus madagascariensis Dejean, 1831 ), by original designation.

Parhalus Jeannel, 1946: 160 , 162 (unavailable).

Parhalus Jeannel, 1948: 674 [as subgenus of Harpalus ]. Type species: Harpalus madagascariensis Dejean, 1831 , by original designation.

Diagnosis. Body glabrous, impunctate, in most species punctures absent even on pronotum basally. Head without fronto-ocular furrows. Paraglossae glabrous, wide, rounded apically ( Figs 48, 49 ). Mentum with median tooth. Epilobes narrow. Pronotal basal margin glabrous, not ciliate. Elytra with one discal setigerous pore on interval 3 (occasionally absent on one elytron) and without discal pores on intervals 5 and 7. Elytral umbilicate series more or less continuous, without wide gap at middle. Metafemur ventrally with three or four setae along posterior margin. Metatarsus with tarsomere 1 notably shorter than tarsomeres 2 and 3 combined. Pro- and mesotarsomeres 1–4 of male dilated and with biseriate adhesive vestiture ventrally. Last visible abdominal sternite (VII) without pronounced sexual dimorphism, with two pairs of marginal setigerous pores in both sexes. Gonocoxite with several rather long and fine setae on dorsal edge of outer side ( Figs 50, 51 ). Median lobe of aedeagus with apical orifice shifted to the left (as in Figs 52 and 53 ), with or without apical capitulum.

Microsculpture: isodiametric on head, isodiametric to moderately transverse on disc of pronotum, markedly transverse or strongly obliterate, without distinct meshes, on elytral disc, and isodiametric on two or three lateral intervals.

Composition and distribution. The genus comprises the following 15 species from Madagascar, Reunion and Mauritius islands (asterisk before species name means that the type material was examined): * Anisochirus chalcopterus ( Jeannel, 1948) ( Madagascar) , * A. seyrigi ( Jeannel, 1948) ( Madagascar) , * A. impressicollis ( Jeannel, 1948) ( Madagascar) , * A. pachys ( Jeannel, 1948) ( Madagascar) , * A. tenuestriatus ( Jeannel, 1948) , with two subspecies—the nominotypical one and * A. tenuestriatus sicardi ( Jeannel, 1948) , both from Madagascar, * A. stricticollis ( Jeannel, 1948) ( Madagascar) , * A. obtusiusculus ( Jeannel, 1948) ( Madagascar) , * A. emarginatus ( Dejean, 1829) ( Reunion) , * A. madagascariensis (Dejean, 1931) (= * A. alluaudi Jeannel, 1946 ) ( Madagascar), * A. lampronotus ( Jeannel, 1948) ( Madagascar) , * A. brunnipes ( Dejean, 1829) ( Reunion and Mauritius), A. pecinai ( Hovorka, 2006) ( Reunion) , A. poussereaui (Facchini et Giachino, 2011) ( Reunion) , * A. sinuatipennis ( Jeannel, 1948) ( Madagascar) , and * A. imerinae ( Jeannel, 1948) ( Madagascar) .

Comparison. In combination of characters, including the lateral position of the apical orifice of the aedeagus, the species of Anisochirus are very similar to those of Harpalus , but distinctly differ from them in glabrous paraglossae. In all examined species of Harpalus , the paraglossae are setose at margins, at least with one distinct marginal seta on one of the paraglossae (in some Afrotropical members). The species of Anisochirus also differ from most of the Afrotropical representatives of Harpalus in the features of the elytral microsculpture, which, if present, consists of the markedly transverse meshes on the disc (versus isodiametric to moderately transverse meshes in the Afrotropical Harpalus ).

In external morphological characters, including glabrous paraglossae, Anisochirus is very similar to the Madagascan genus Ectinothorax Alluaud, 1941 , but distinguished from it by having the body less elongate, mesotarsomere 1 constantly dilated and with adhesive vestiture ventrally (in some Ectinothorax , pro- and mesotarsi are not dilated) and median lobe of aedeagus with apical orifice shifted to the left. In addition, the elytra of Ectinothorax are probably constantly without discal setigerous pores and with umbilicate marginal series more or less widely interrupted medially.

Remarks. Jeannel (1946, 1948) regarded the Harpalus species from Madagascan region as well as from East and Southern Africa as belonging to the separate subgenus Parhalus based on shape of their pronotal basal angles, which, according to this author, are rounded, with indistinct apices, as opposed to those of the Palaearctic species, which are distinct, right or almost right. Such treatment was not accepted by Basilewsky (1951) and other researchers because shape of the pronotal basal angles is very variable both in the African and Holarctic species and no other distinctive characters were proposed. However, according to our data, the Madagascan species, including H. madagascariensis , the type species of Parhalus , are distinguished from all other Harpalus , both from the Holarctic and Ethiopian regions, by glabrous paraglossae and thus represent a separate taxon endemic to Madagascar, Reunion and Mauritius. The valid name of this taxon should be Anisochirus since Parhalus is its junior synonym. Jeannel (1946, 1948) and Basilewsky (1950) erroneously considered the monobasic Anisochirus as belonging to the subtribe Anisodactylina ( Noonan 1973) . My examination of the holotype of Anisochirus alluaudi ( Fig. 47 ), the type species of Anisochirus , confirmed its synonymy with Harpalus madagascariensis . Interestingly, among the examined Madagascan species, only Harpalus rivalsi Jeannel, 1948 from Reunion Island has paraglossae setose, but this species is also characterized by isodiametric elytral microsculpture and very similar in its distinctive characters to H. hybridus Boheman, 1848 (= H. agilis sensu Basilewsky, 1951 ), a species widely distributed in Southern Africa. Since their aedeagi are also very similar, these two species are apparently closely related and most likely represent a sister pair. In the modern view, the fauna and flora of Madagascar includes ancient (Cretaceous) elements, as well as majority of Cenozoic migrants with their closest relatives in either Africa or Asia ( Crottini et al. 2012, Buerki et al. 2013). According to Yoder & Nowak (2006), most of the recent biota of Madagascar comprises “the descendents of Cenozoic dispersers, predominantly with African origins”. In my opinion, the ancestral form of H. rivalsi penetrated to Reunion from Southern Africa in more recent time than the ancestor of Anisochirus .

Though the rank of Anisochirus needs further study, I now prefer to consider it as a genus, which is probably more closely related to Ectinothorax than to Harpalus since the shifting of apical orifice of aedeagus to the left (apomorphic feature) occurred in different lines of Harpalini independently (see, for example, Antoine 1959, Kataev 1995b). For example, the diverse genus Trichotichnus Morawitz, 1863 , also possessing glabrous paraglossae and only one discal pore on elytral interval 3, includes taxa with differing position (dorsal and lateral) of the apical orifice of the aedeagus (Kataev 2020). The setose paraglossae are considered to be an apomorphic character for Harpali and some other groups because in most taxa of Harpalini (as well as Carabidae ) they are glabrous ( Kataev 2009). The glabrous paraglossae of Anisochirus may be treated either as a plesiomorphic character or as a reversion to the plesiomorphic state if the ancestor of Anisochirus originated from the Afrotropical Harpalus with setose paraglossae and lost setae already in Madagascar. In the latter case, Anisochirus should be treated as a subgenus of Harpalus . The latter assumption can be supported by the fact that in contrast to the Holarctic Harpalus having constantly several marginal setae on each paraglossa, in the Afrotropical species the number of setae on paraglossae is highly variable, and occasionally only one seta is present on one of the paraglossae. It is known that wide variation of basal diagnostic features is a characteristic of taxa located at basis of large phylogenetic branches ( Mamkaev 1968, 1979, Kataev 2012). However, I don’t know any other case of such possible reversion in paraglossa setation among Harpalini . Based on the glabrous paraglossae and elytra with at most only one discal setigerous pore on interval 3, Anisochirus and Ectinothorax can formally be included in the Trichotichni genus group sensu Ball & Bousquet (2001), but taking into account that most of the morphological distinctive characters of Harpalus and related genera are homoplasies ( Kataev 2009), the true relationships of Anisochirus as well as Ectinothorax can be established only on the basis of additional detailed research, including molecular analysis.

Figures

FIGURE 47. Anisochirus madagascariensis (Dejean, 1831) (holotype of A. alluaudi Jeannel, 1946), habitus. Scale bar = 1.0 mm.

FIGURES 48–53. Anisochirus spp. 48, A. brunnipes (Dejean, 1829) (Reunion); 49–53, A. madagascariensis (Dejean, 1831) (Madagascar). 48, 49, labium; 50, laterotergite, gonosubcoxite, and gonocoxite; 51, gonocoxite; 52, 53, median lobe of aedeagus. Ventral (48–50), lateral (51, 52) and dorsal (53) views. Scale bars: A = 0.5 mm (48–51), B = 1.0 mm (52, 53).