Histeromorphus Kraatz, 1865

Purchart, Luboš, 2014, Revision of the genus Histeromorphus (Coleoptera: Tenebrionidae) from the Socotra Archipelago with descriptions of three new species *, Acta Entomologica Musei Nationalis Pragae 54, pp. 211-230 : 213-215

Genus Histeromorphus Kraatz, 1865

Histeromorphus Kraatz, 1865:11 (original description). Type species: Histeromorphus plicatus Kraatz, 1865: 12 (by monotypy); WATERHOUSE (1881): 473 (description of new species); GAHAN (1900): 8 (description of new species); GAHAN (1903): 273 (redescription of species, new records); LESNE (1915): 228 (redescription, key to species, description of new species); GRIDELLI (1931): 221 (figure); GEBIEN (1937): 547 (catalogue); KOCH (1943): 498 (key to genera of Erodiini ); KOCH (1970): 90 (description of variability); SCHAWALLER (2004): 441 (new records); LÖBL et al. (2008): 148 (catalogue).

Redescription. Body length 7.1–13.1 mm. Body width 4.8–9.4 mm. Black, dull, glabrous. Body broad, oval.

Head relatively large, smooth, slightly or densely punctate, widest at level of genae. Labrum pale brown, strongly exposed, surface sparsely covered with long yellow setae that become denser on lateral and anterior margins; anterior margin slightly sinuate. Anterior margin of clypeus straight or slightly to strongly sinuate. Clypeus punctate, frontoclypeal suture slightly indicated laterally or sometimes not visible. Mandibles flat laterally, bifid. Maxillary palpus with last palpomere slightly widened, with corona of setae on apical margin. Mentum large, transverse, trapezoid, widest towards apex, apically with two lateral convexities and central fissure. Submentum transverse, triangular. Eyes narrow, vertically elongate. Antennae relatively short, approximately as long as width of head, glabrous, usually with several setae on apical margin of apical three antennomeres, antennomere III elongate, longer than following antennomere, penultimate antennomere largest, apical antennomere rudimentary.

Pronotum strongly transverse, at least twice as broad as long, smooth or very slightly punctate. Sides of pronotum completely rounded or with straight posterior half. Anterior margin broadly and deeply sinuate, anterior corners sharp or obtuse angled. Posterior margin bisinuate, posterior corners sharp or obtuse. Lateral margin complete, anterior margin partly bordered, posterior margin and middle of anterior margin unbordered, obliterated.

Elytra broad, with broadly rounded sides. Scutellum not visible. Elytral surface variable (smooth, irregularly plicate, with longitudinal zigzag elytral striae or with transverse wavy lines). Pseudopleura broad, smooth, separated from elytra by complete or incomplete pseudopleural margin of elytra. Elytra coarctate at elytral suture. Wings not developed.

Ventral part. Prosternum glabrous, smooth or slightly wrinkled, impunctate. Prosternal apophysis as broad as procoxae, widened posteriad. Mesoventrite glabrous, smooth or wrinkled; as long as or longer than coxae. Metaventrite glabrous, smooth or wrinkled; as long as coxae. Abdominal ventrites glabrous, smooth or wrinkled and with small granules.

Legs sparsely covered with short and fine setae or glabrous. Protibia strongly flattened, widened anteriad, projected in finger-like tooth on lateral side of protibia; above the latter on lateral side of protibia another, much smaller tooth is situated. Profemur distinctly claviform. Inner anterior angle of all tibiae with two large spines.

Male genitalia. Aedeagus simple (Figs 29–51), inverted, i.e. tegmen ventral and median lobe dorsal (cf. WATT 1974).

Female genitalia. Ovipositor with spatulate apical coxite lobes (Figs 52–61) which are considered one of the tribal features of Erodiini ( DOYEN 1993) .

Distinct sexual dimorphism not present. Sometimes males possess somewhat slightly flattened abdominal ventrites contrary to convex ventrites in females.

Differential diagnosis. The tribe Erodiini presently contains 36 genera ( SCHAWALLER 1990). Most of these genera possess long setae on the inner side of protibiae. On the contrary the genus Histeromorphus , together with the genera Amnodeis Miller, 1858 , Ammodoides Lesne, 1915 , Anodesis Solier, 1834 , Arthrodion Lesne, 1915 , Diodontes Solier, 1834 and Somalammodes Koch, 1943 , belongs to the generic group of Erodiini which is characterized, and can be distinguished from the previous generic group, by the absence of long setae on the inner side of protibiae. Histeromorphus differs from the genera Arthrodion and Diodontes in the absence of a keel above the inner margin of the eye (the latter two genera possess a long keel above it – subocular keel). From Amnodeis and Anodesis , Histeromorphus can be distinguished by flat mandibles, glabrous antennae, elytra without granulate or keeled punctation, and its small size (in the latter two genera the mandibles are keeled dorsally and ventrally, basal antennomere is covered densely with hairs, elytra granulate or often with 1–2 keels, and they are larger). From Ammodoides and Somalammodes , Histeromorphus differs in strongly broad body with rounded sides, and glabrous (not punctate) surface (dorsal and ventral part); clypeus large, flat with emarginate anterior margin and tooth-like anterior corners (bidentate) or the anterior margin is straight. In the latter two genera the body is much smaller and narrower, parallel sided with punctate surface (dorsal and ventral part); clypeus small, short and tridentate ( Ammodoides ) or with emarginate anterior margin (bidentate) but in this case the clypeus is bent down towards the labrum and its posterior part (margin) is transversely protuberant ( Somalammodes ).

Remark. The differential diagnosis is based mainly on Koch’s paper and his key to the genera of the tribe Erodiini ( KOCH 1943) . All the above mentioned characters were personally verified in the following species (all deposited in the MNHN): Ammodoides draceanarum Koch, 1960 , A. lateripunctatus (Fairmaire, 1890) , Amnodeis milleri Reitter, 1914 , A. confluens Miller, 1858 , A. asiaticus Miller, 1858 , A. intermedius Reitter, 1914 , A. giganteus (Reiche & Saulcy, 1857) , A. gebieni Reitter, 1914 , Anodesis cleryi Solier, 1834 , Arthrodion africanum (Fairmaire, 1882) , Diodontes porcatus Solier, 1834 , D. areolatus Gerstäcker, 1871 , D. chatanayi Lesne, 1915 , D. subscutellatus Lesne, 1915 , and D. patrizii Gridelli, 1939 .

Distribution. The tribe Erodiini is distributed in Africa, the Mediterranean region, the Middle East, and South ( India only) and Central Asia ( SCHAWALLER 1990). The genus Histeromorphus is endemic to Socotra Archipelago ( BATELKA 2012).