Definition and Revision of the Orthrius-group of genera (Coleoptera, Cleridae, Clerinae)

Abstract An “Orthrius-group” of genera is proposed, and defined to include Aphelochroa Quedenfeldt, 1885; Caridopus Schenkling, 1908; Dozocolletus Chevrolat, 1842; Gyponyx Gorham, 1883; Languropilus Pic, 1940; Orthrius Gorham, 1876; Pieleus Pic, 1940; Xenorthrius Gorham, 1892; plus three new genera Neorthrius gen. n., Nonalatus gen. n. and Pseudoastigmus gen. n. A phylogeny of the 11 constituent Orthrius-group genera (analysis of 22 morphological characters using Clerus Geoffroy as the out-group taxon was performed with TNT v1.1) is proposed. Four genera are synonymised: Burgeonus Pic, 1950, syn. n. (with Aphelochroa Quedenfeldt, 1885); Brinckodes Winkler, 1960, syn. n. and Quasibrinckodes Winkler, 1960, syn. n. (both with Dozocolletus Chevrolat, 1842); and Dedana Fairmaire, 1888, syn. n. (with Orthrius Gorham, 1876). The genera Falsoorthrius Pic, 1940 and Mimorthrius Pic, 1940 are transferred from Clerinae to the subfamily Tillinae.


Introduction
Th e checkered beetles (Cleridae and Th anerocleridae) contain approximately 3600 described species, which are classifi ed into seven subfamilies (Lawrence and Newton Jr. 1995) and involve 303 genera. By far, the Clerinae is the most specious subfamily with approximately 45% of the species of the family. Checkered beetles are largely tropical insects with an approximate faunal distribution as follows: 1030 species in the Afrotropics, 840 in the Neotropics, 690 in the Orientalis, 510 in the Australis and 490 in the Palaearctis (Gerstmeier 2000).
Th e higher classifi cation of the Cleridae has undergone considerable categorical oscillations (Opitz 2002(Opitz , 2010. Several landmark publications of Crowson (1955Crowson ( , 1964Crowson ( , 1966Crowson ( , 1970 form the basis for a modern classifi cation of Cleroidea, while some nomenclatural amendments were made by Lawrence and Newton Jr. (1995). More recently, signifi cant contributions dealing with suprageneric taxa include the elevation of Th aneroclerinae (Kolibáč 1992(Kolibáč , 2004 and Metaxina Broun, to family rank (Kolibáč 1992(Kolibáč , 2004, the proposition of two subfamily classifi cations (Kolibáč 1997, Opitz 2010) plus revisions of the genera and species of Epiphloeinae (Opitz , 2004(Opitz , 2005(Opitz , 2006(Opitz , 2007(Opitz , 2008a(Opitz , 2008b(Opitz , 2008c, the genera of Hydnocerinae (which included a tribal classifi cation for that subfamily) (Kolibáč 1998) and the Australian Korynetinae (Kolibáč 2003). Nevertheless, some discontinuities are obvious and not all changes made at the subfamily-level are universally accepted among cleridologists. From a world viewpoint, much remains to be done with clarifi cation of generic concepts and zoogeographic relationships at supraspecifi c levels (Opitz 2002). In our opinion, Opitz's (2010) concept of 12 subfamilies seems to result in the best system. Th e Clerinae is the largest of all subfamilies of the Cleridae and the most diffi cult in which to defi ne generic limits (Chapin 1924). Furthermore, the paucity of clearly defi ned morphological gaps among these genera renders their generic delimitation very diffi cult. A paper dealing with genera related to Clerus Geoff roy (Gerstmeier 2002) represents an initial step in clarifying generic limits within Clerinae. After an extensive review of Indo-Australian clerid material, a generic concept of clerine genera such as Clerus Geoff roy, 1762, Omadius Laporte, 1836, and Stigmatium Gray, 1832 became apparent and resulted in a preliminary concept of "Clerus-series" (Gerst meier 2002).
A recent revision of the genus Xenorthrius Gorham (Gerstmeier and Eberle 2010) represents besides Mawdsley's (1994) revision of the genus Aphelochroa the second in a series of papers dealing with the genera of a so-called "Orthrius-group". In the Xenorthrius revison 11 species were transferred from Orthrius to Xenorthrius, and 22 new species were described, so that the genus Xenorthrius now includes 50 species (from 20 species formerly listed in Corporaal 1950). Th e aim of the present paper is to defi ne the characters for a generic group, to determine those genera constituting the Orthrius group and examine the relationships among those genera. Th e following genera have been taken into consideration: Aphelochroa Quedenfeldt, 1885, Caridopus Schenkling, 1908, Dozocolletus Chevrolat, 1842, Gyponyx Gorham, 1883, Languropilus Pic, 1940, Neorthrius gen. n., Orthrius Gorham, 1876, Pieleus Pic, 1940, Nonalatus gen. n., Pseudoastigmus gen. n., Xenorthrius Gorham, 1892, Falsoorthrius Pic, 1940and Mimorthrius Pic, 1940 (during this study, the latter two genera were discovered to belong to the subfamily Tillinae). Gorham (1876) described the genus Orthrius for Orthrius cylindricus and noticed the relationship to Th anasimus, and, on the basis of the tarsal structure, to Clerus. Seven years later, the same author (Gorham 1883) established the genus Gyponyx and mentioned its relationship to Th anasimus and Axina. Chevrolat (1842) described the species "oblongus", drawing attention to its fl ightlessness and established the genus Dozocolletus, without a generic diagnosis; a diagnosis was given later by Lacordaire (1857). Quedenfeldt (1885) described the genus Aphelochroa (with A. carneipennis as type species) comparing it with Opilo and Natalis. Later, Gorham (1892) established the new genus Xenorthrius for three new species (X. balteatus, X. mouhoti and X. subfasciatus). For another two wingless species Schenkling (1908) erected the genus Caridopus and in the same publication, described the species Apteroclerus brevis from the Kilimanjaro, though with reservations about its generic placement. In two diff erent publications Pic (1940aPic ( , 1940b respectively described the genera Languropilus and Pieleus, while in an earlier paper (Pic 1933), he had expressed his view that the fl ightless Astigmus pygidialis diff ers greatly from all other Astigmus species.

Cladistic analysis
23 characters with their respective states (Tab. 1) were analysed. Character polarity was determined by the outgroup method (Nixon and Carpenter 1993); no ancestral states were forced. Th e genus Clerus Geoff roy, 1762, was considered the outgroup taxon. Th e data matrix (Tab. 2) was analysed with the Willi Hennig Society edition of TNT 1.1 from September 2009 (Goloboff et al. 2003(Goloboff et al. , 2008. To receive an exact solution, every possible tree was computed by using the "implicit enumeration" routine. For characters with more than one state per genus, multiple character states were used; they appear enclosed by square brackets in the matrix. Characters that were ambiguous, or missing in the available specimen, appear as a question mark. All characters were chosen to be nonadditive and none were weighted. Implied weighting was also turned off . Th e species were sorted alphabetically within the input fi le.

Diagnosis
Species of the Orthrius-group are readily distinguished from other Clerinae by the presence of the following characters (in combination): -Eyes distinct, more or less protruding laterally, coarsely facetted -Eyes separated by more than one eye width -Labrum bilobed to broadly V-shaped (  Head: Eyes strongly protruding, only slightly emarginate at antennal insertion; interocular space more than one eye width; gular sutures converging, gular process broad; A1 large, stout, almost twice as long as A2, A2 shorter than A3, A3-A8 fi liform, antennomeres becoming shorter, A9 dilated distally, A10 broader than long, A11 subovate, apical third pinched, terminal three antennomeres forming a loose club. Th orax: Proepimeron short, not acute; anterior mesosternal process absent; proepimeron short; metendosternite with normal furcal stalk, short, normal furcal  arms and very slightly emarginate stalk base (Fig. 11). Elytra long, subparallel, broadest behind middle, apices broadly rounded, elytral punctation not arranged into striae.
Head: Eyes strongly protruding, conspicuously emarginate at antennal insertion; interocular space larger than one eye width; gular sutures subparallel to divergent, gular process varying in width, from narrow to broad; antennal length interspecifi cally variable and sometimes sexually dimorphic (longer in males), A2 shorter than A3, A3-A8 more or less fi liform, A10 broader than long, A11 sub-ovate, apical half pinched, mostly without club, sometimes terminal three antennomeres forming a loose club.

Discussion of cladistic results
Th e cladistic analysis resulted in a single most parsimonious tree with a length of 37 steps (Fig. 69). Common to all taxa of the Orthrius-group are four mesotarsal pulvilli (char. 0-0) and coarse ommatidial facets (char. 5-0) which distinguishes them from the Clerus-series.
Pseudoastigmus gen. n. and Nonalatus gen. n. appear together at the base of the tree. Th is pair is supported by the acute form of the furcal arms of the metendosternite (char. 14-1) as well as the complete reduction of the hind wings (char. 16-1).
Th e remaining taxa share the fi liform fl agellum (char. 6-0). Th e development of four pulvilli at the metatarsus (char. 1-0) is also synapomorphic at this point, but is  reduced to three pulvilli for the cluster of Neorthrius gen. n., Languropilus, Orthrius and Aphelochroa (char. 1-1). These four genera also share the loss of the anterior mesosternal process (char. 12-1). Like in Dozocolletus and Caridopus the emargination of the eyes is weak or absent (char. 7-0) in Languropilus, Orthrius and Aphelochroa. For this reason, Neorthrius adopts a basal position in this group. The monophyly of Orthrius and Aphelochroa is supported by their elytral punctation (char. 19-2). Orthrius differs from all other taxa in this revision in its tibial spur formula which is 0-1-1 (chars. 2-2, 3-1 and 4-1).
Th e aethiopian genera Gyponyx, Dozocolletus and Caridopus have in common, that the phallobasic struts are fused with the phallobasic apodeme (char. 22-1). Th e monophyly of Dozocolletus and Caridopus is well supported by the weak or absent emargination of the eyes (char. 7-0) and similarities of their metendosternites: the furcal arms are acute (char. 14-1) and the furcal stalk base (char. 15-1) is deeply emarginate.
A common ancestor can be assumed for the latter two clusters of genera.Th is is supported by two synapomorphies: the gular sutures are convergent to parallel (char. 9-0) and the claws are simple (char. 21-0). Th e presence of the tibial carinae (char. 20-0) also is apomorphic at this node but reduced in Caridopus and Languropilus. As Solervicens (2007) mentioned, it also may be considered a symplesiomorphy, because it is a common character of the Clerinae.