Malagasyprinus caeruleatus (Lewis, 1905) Lewis, 1905

Lackner, Tomas & Gomy, Yves, 2013, Malagasyprinus, a new genus of the Saprininae from Madagascar with description of two new species (Coleoptera, Histeridae, Saprininae) (First contribution to the knowledge of the Histeridae of Madagascar), ZooKeys 333, pp. 55-76 : 58-63

Malagasyprinus caeruleatus (Lewis, 1905) comb. n. Figs 1-22

Saprinus caeruleatus Lewis, 1905: 611; Mazur (1997): 220; Mazur (2011): 180.

Type locality.

Madagascar, Androy region, Ambovombe.

Type material examined.

MADAGASCAR: LECTOTYPE (present designation): Male, mounted in Entofix on its right side, with male terminalia extracted and glued to the same card, with the following labels: “♂”; (white, hand-written label); "Plateau de l’Androy, rég. D’Ambovombe” (light-blue, printed label); “Madagascar” (white label, narrow and long, printed); "G. Lewis Coll. B.M. 1926-369" (white label, elongate, printed and characteristic of the specimens originating from G. Lewis’ collec tion); " Saprinus caeruleatus Lewis Type" (white, hand-written label of Lewis); “TYPE” (white round label with red margin, printed); "Y. Gomy des. Lectotype" (red, printed label); " Saprinus (s.str.) coeruleatus Lew., Y. Gomy Det. 2006" (printed-written determination label) (NHM).

Additional material examined.

5 ♂♂ & 3 ♀♀ and 49 exs. (sex undetermined) "Mikea Forest / Feb. 2004"; dry forest / fish baited trap / Ilkka Hanski leg"; 1 ♀: "Toliara / Prov., Ranobe, elev. 30m / 23°02'03"S, 043°36'43"E / 5-9 February 2003; Frontier Wilderness / Project, sifted litter (leaf mold / rotten wood) in spiny forest / thicket code: MGF056"; 1 ♀, "Madagascar Sud-Ouest / LAMBOMAKANDRO 500m / Tuléar / vii-57 Andria R"; "Institut / Scientifique / MADAGASCAR".

Re-description. Body measurements: PEL: 2.05-2.30 mm; APW: 0.75-0.85 mm; PPW: 1.65-1.80 mm; EL: 1.10-1.30 mm; EW: 1.90-2.10 mm.

Body (Figs 1-4) roundly oval, convex, cuticle entirely pitch-black with dark blue metallic hue, shining; legs, mouthparts and antennae light red-brown.

Antennal scape (Fig. 6) slightly thickened, with shallow sparse punctures and three short setae; antennal club (Fig. 5) round with slightly pointed tip, without visible articulation, entire surface with dense short sensillae intermingled with sparser longer erect sensillae; sensory structures of antennal club in form of a single oval sensory area situated on internal distal part of the antennal club with a corresponding stipe-shaped vesicle situated underneath (Fig. 22).

Mouthparts. Mandibles (Fig. 6) with rounded outer margin, laterally with deep dense punctures, moderately curved inwardly, mandibular apex pointed; sub-apical tooth on inner margin of left mandible large, almost perpendicular; labrum (Fig. 6) convex, imbricate; labral pits deep, each with two well-sclerotized long setae; terminal labial palpomere elongated, its width about half its length; mentum sub-trapezoid, anterior angles slightly produced; anterior margin (Fig. 7) medially with slight emargination surrounded with six long setae, lateral margins with row of sparse shorter ramose setae, several setae present also on disc of mentum; cardo of maxilla with few short setae; stipes triangular, with three short setae; terminal maxillary palpomere elongated, its width about one-third its length, approximately three times as long as penultimate.

Clypeus (Fig. 6) rugulose-lacunose, slightly depressed medially, sloping down laterally, faintly margined by prolonged frontal stria; frontal stria largely interrupted medially, for short distance prolonged onto clypeus, supraorbital stria well impressed, carinate; frontal disc (Fig. 6) depressed, coarsely and densely punctate, rugulose-lacunose; eyes strongly convex, well visible from above.

Pronotal sides moderately (Figs 1, 3) narrowing anteriorly, apical angles blunt, pronotal depressions absent; sides of pronotal disc with moderately deep longitudinal depression covered in deep longitudinal wrinkles, medially wrinkles disappear and become coarse and dense punctures; surface between longitudinal depression and pronotal margin slightly convex, punctate; marginal pronotal stria complete, laterally carinate and visible along its entire length from dorsal view; pronotal disc medially convex; pronotal hypomeron glabrous; scutellum small, but visible.

Elytral epipleura evenly punctate; marginal epipleural stria fine, complete; marginal elytral stria straight, well impressed and slightly carinate, continued as complete apical elytral stria. Humeral elytral stria weakly impressed on basal third, almost invisible under punctuation; inner subhumeral stria obliterated by coarse punctures; dorsal elytral striae (except for a tiny basal fragment of fourth dorsal elytral and complete sutural stria) completely erased by extremely coarse and dense elytral punctuation; fourth dorsal elytral stria present as short basal fragment connected with complete sutural elytral stria, which is apically connected with apical elytral stria; entire elytral disc (with exception of tiny punctate ‘mirror’ on fourth elytral interval) with extremely coarse and dense punctures, separated by less than half of their diameter; punctuation somewhat weakens before elytral apex.

Propygidium and pygidium (Fig. 10) densely and coarsely punctate, punctures separated by less than half of their diameter.

Anterior margin of prosternum (Fig. 8) almost straight; marginal prosternal stria present laterally; prosternal process on apical two-thirds concave, surface between carinal prosternal striae imbricate, laterally imbricate-punctate, punctures shallow; carinal prosternal striae well-impressed, carinae slightly divergent on prosternal apophysis, medially convergent and thence again divergent anteriorly, apically united under narrow loop; prosternal foveae large and deep; lateral prosternal striae carinate, sub-parallel, apically terminating near pre-apical foveae.

Anterior margin of mesoventrite almost straight, with median projection; discal marginal mesoventral stria well impressed, carinate, inwardly arcuate medially; disc of mesoventrite imbricate-punctate, punctures deep; meso-metaventral sutural stria undulate; intercoxal disc of metaventrite slightly depressed medially, with scattered round punctures of various sizes; lateral metaventral stria (Fig. 9) well impressed, carinate, al most straight, shortened; lateral disc of metaventrite (Fig. 9) slightly concave, with dense shallow punctures; metepisternum (Fig. 9) with even denser and coarser punctuation, punctures deeper than those of lateral disc of metaventrite; fused metepimeron with somewhat sparser punctures; metepisternal stria present only on fused metepimeron.

Intercoxal disc of the first abdominal sternite completely striate laterally; surface imbricate-punctate, punctures fine and sparse.

Protibia (Fig. 11) slightly dilated, outer margin with seven moderately large triangular teeth topped by short rounded denticle, diminishing in size in proximal direction; setae of outer row very short and sparse; protarsal groove deep, substrigulate; anterior protibial stria shortened apically; setae of median row shorter than those of outer row; two tarsal denticles present near tarsal insertion; protibial spur short, bent, inserted on apical margin of protibia; apical margin of protibia posteriorly with one tiny denticle; outer part of posterior surface imbricate, separated from imbricate me dian part of posterior surface by vague boundary and row of short sclerotized setae; posterior protibial stria complete, with a sparse row of tiny sclerotized setae becoming thicker apically; inner row of setae single, setae sparse and short.

Mesotibia slender, outer margin with two rows of sparsely spaced short denticles; setae of outer row regular, sparse, shorter than denticles; setae of median row regular, microscopic; posterior mesotibial stria complete; anterior surface of mesotibia imbricate; anterior mesotibial stria complete; mesotibial spur short; apical margin of mesotibia anteriorly with two short denticles; claws of apical tarsomere slightly bent, shorter than half its length; metatibia more slender and longer than mesotibia, in all aspects similar to it, but denticles on outer margin much sparser and claws of apical tarsomere slightly longer than half its length.

Male genitalia. Eighth sternite (Figs 12-13) fused medially, apically with short velum; apex fringed with two short setae; eighth tergite and eighth sternite fused laterally (Fig. 14). Ninth tergite (Figs 15-16) longitudinally fused medially, typical for the subfamily; spiculum gastrale (Figs 20-21) expanded on both ends; basal end with median emargination, not arcuate outwardly. Aedeagus (Figs 17-19) dilated medially; basal piece of aedeagus short, ratio of its length: length of parameres 1:5; parameres fused along their basal half; apex of aedeagus (Fig. 18) curiously split in two pointed halves curved inwardly; aedeagus strongly curved ventrad (Fig. 19).

Differential diagnosis.

From the highly similar Malagasyprinus perrieri sp. n., Malagasyprinus caeruleatus differs by smaller size; darker elytral cuticle (the elytra of Malagasyprinus perrieri are brown to dark brown whereas those of Malagasyprinus caeruleatus are pitch-black; compare Figs 1 and 26) shallower lateral longitudinal pronotal depression, and coarser elytral punctuation (in Malagasyprinus perrieri the elytral striae are more discernible whereas they are almost completely obliterated by punctuation in Malagasyprinus caeruleatus ); furthermore, the elytral ‘mirror’ is often larger and less densely punctate in Malagasyprinus perrieri whereas it is tiny and often densely punctate in Malagasyprinus caeruleatus . The shape of carinal prosternal striae is likewise different between the two species: in Malagasyprinus caeruleatus they are strongly bi-sinuate, approximate medially and diverging, connected by a round loop, whereas in Malagasyprinus perrieri they are only slightly bi-sinuate, occasionally even sub-parallel (compare Figs 8 and 32) and furthermore, the prosternal process is medially deeply depressed in Malagasyprinus caeruleatus , whereas it is only slightly so with Malagasyprinus perrieri . However, the best marked differences are found among the aedeagi of the two species: in Malagasyprinus caeruleatus it is apically split in two inwardly curved halves resembling a snake’s tongue and in Malagasyprinus perrieri it is simply pointed apically and not split (compare Figs 18, 25 and 40). From Malagasyprinus diana sp. n., Malagasyprinus caeruleatus differs by its shallower lateral longitudinal depression of pronotum; furthermore, the deep longitudinal wrinkles occupy almost the entire pronotal disk in Malagasyprinus diana , whereas they are present mostly only in and around the longitudinal lateral pronotal depression with the median part of pronotum bearing simple punctures in Malagasyprinus caeruleatus . The elytral ‘mirror’ is proportionally larger in Malagasyprinus diana than in Malagasyprinus caeruleatus and it bears only sparse and fine punctures in Malagasyprinus diana , whereas it is coarsely and densely punctate in Malagasyprinus caeruleatus (compare Figs 1 and 44). More marked differences are found again between the shape of the carinal prosternal striae of the two taxa: those of Malagasyprinus caeruleatus are medially approximate and diverge anteriorly where there are connected by a round loop, whereas the carinal prosternal striae of Malagasyprinus diana are not approximate medially, slightly diverging on apical half (compare Figs 8 and 50). Prosternal process of Malagasyprinus caeruleatus is depressed on apical two-thirds whereas it is even in Malagasyprinus diana . Male aedeagi are likewise very different: the one of Malagasyprinus diana resembles that of Malagasyprinus perrieri , whereas the one of Malagasyprinus caeruleatus is unique with its split apex (compare Figs 18 and 60).

Distribution. Known exclusively from the south of Madagascar, regions of Antsimo-Andrefana, Androy and Anosy (Fig. 62).

Biology. Collected in dry forest by pitfall traps, as well as by sifting litter in spiny forest and/or thicket.