Massimo, Sciaky & Massimo, 2024

Sciaky, Riccardo & Massimo, Niccolò, 2024, A new subgenus and species of Crepidogaster from Madagascar (Coleoptera: Carabidae, Brachininae, Crepidogastrini), Fragmenta entomologica 56 (1), pp. 73-76 : 74-76

Subfamily Brachininae Bonelli, 1810 Tribe Crepidogastrini Jeannel, 1949 Genus Crepidogaster Boheman, 1848

Sphaerotyronia Sciaky & Massimo , subg. nov.

Diagnosis: A subgenus of Crepidogaster morphologically closely related to the subgenus Tyronia . Two pairs of lateral setae on pronotum, last palpomere of both labial and maxillary palps swollen and globose, not truncate. Labrum with 12 setae and a deep indentation in the center of its anterior margin.

Derivatio nominis: The name of the subgenus is composed by the suffix “-tyronia”, which refers to the simi- larity of this species to the subgenus Tyronia Liebke , and the prefix “Sphaero-” (from Latin “ sphaera ”, meaning “sphere”), which refers to the unusual shape of the elytra of the only known species.

Systematic considerations: This new subgenus seems rather closely related to Tyronia and much less to Crepidogaster s.str. We maintain many doubts on the reunion of the two former genera, because, except a few doubtful species, the bulk of them seem clearly attributable to one or the other genus. There are also other instances of genera of the same group with a doubtful position, for instance the genus Crepidolomus Basilewsky, 1959 , is a highly modified genus evidently more related to Tyronia than to Crepidogaster ( Mateu 1986) . Waiting for a more complete revision of the whole complex of genera that will clear the systematic position of each included taxa, we prefer to keep the two taxa at least separate at the subgeneric level, while Sphaerotyronia remains as a third subgenus, clearly more closely allied to Tyronia than to Crepidogaster s.str.

Crepidogaster (Sphaerotyronia) rotundata Sciaky & Massimo, sp. nov.

(Figs 1-3)

Diagnosis: A small species of Crepidogaster (Sphaerotyronia) from Madagascar, characterized by elytra extremely enlarged laterally, almost circular. Body stout, testaceous-brown. Aedeagus with a developed, strongly recurved base and a ventral margin linear, not curved and slightly sinuous at apex. Apex prolonged in a small rounded lobe.

Type material. Holotype: ♂ (only known specimen). E Madagascar, 130 km E Antananarivo, near Andasibé vill., Feb 2020, A. Sokolov legit, in coll. R. Sciaky, Milan (part of Zoologische Staatssammlung München), Italy.

Description. Male (Figs 1-3). TBL: 4,2 mm. Habitus as in Fig. 1. Body stout, large and relatively flattened in lateral view. Head and pronotum testaceous, with darker spots at the posterior angles of clypeus and on the temples behind the eyes and lateral pronotal edges black. Around the eyes there is a subtle black contour. Dorsal apex of the head, clypeus and labium of a lighter coloration, somewhat yellowish, that gradually darkens along the head and the pronotum. Hind angles of pronotum dark brown, pronotal hypomeron darkened. Elytra brown, lighter on the disc, along the suture and in proximity of the scutellum. Epipleura black. Visible uroterga black. All appendages yellowish, except for mandibles, that are testaceous and whose apex and lower outer margin are black. Antennae yellowish at base, and only slightly darkened toward the apex. Ventral side of body lighter in colour: head and prosternum yellowish, ventrites light brown with darker lateral and hind margins. Pubescence consisting in short yellow setae covering all the body surface (both dorsally and ventrally), slightly less dense on head.

Head. MW (including eyes): 0,9 mm. Head narrow- er than pronotum, subquadrate in dorsal view and pubescent on the whole surface. Eyes large and convex, but only moderately protruding, longer than temples. Frontal furrows subparallel, superficial but visible from the level of the center of the eyes. Within them the punctuation is more pronounced and produces faint diagonal wrinkles. One pair of supraorbital setae present, positioned slightly more distally than the posterior end of the eye. Clypeus trapezoidal, with two setae on each side; anterior margin feebly concave. Microsculpture isodiametric. Labium divided into two lobes by a deep indentation, with 6 setae on each side: 4 setae positioned dorsally (the outermost two significantly longer and more robust than the inner two) and 2 setae inserted on the anterior margin itself, pointing forward (Fig. 2). Mandibles robust, the lateral furrow with a large seta and few smaller hairs. Distal article of both maxillary and labial palps swollen and globose (this feature is more pronounced in labial palpomeres) with apex pointed, not truncate. Antennae rather long, exceeding the base of the pronotum by 4 articles. All antennomeres pubescent, the scapus carrying two more robust setae on the dorsal side before its apex. First 3 antennomeres more slender, antennomeres from 4 to 11 thicker. Apical crown of setae present on all antennomeres except the scapus.

Prothorax. MW of pronotum: 1,0 mm; TL of pronotum (along midline): 1,1 mm. Pronotum as long as wide in correspondence to the point of maximum width, which is positioned almost in the middle. Pronotum wider than head (including eyes). Anterior margin subrectilinear in the center, slightly advanced in correspondence of the anterior angles; posterior margin slightly arched, with hind angles subright and sharp. Base of pronotum narrower than anterior margin. Lateral margins evenly rounded in distal half, sinuous in proximal half, parallel before hind angles. Lateral gutter very narrow and of constant width on all the length of the margin. Two marginal setae: the anterior one positioned near the middle, the posterior one positioned before the hind angles. One basal impression on each side, and a central impression in the proximal half, along the midline. Some transverse wrinkles are visible in the proximal half of pronotum. Microsculpture isodiametric, almost hidden by dense punctuation. Prosternum simple, prolonged in a small and thin process between the procoxae. Central dimple absent. Legs rather short but very slender, with no particular characters.

Elytra. TL (measured along the suture): 1,9 mm; MW (of both elytra together): 2,4 mm. Elytra remarkably short and laterally enlarged, so that from above they assume a circular shape; their width about 2,5 times the maximum width of the pronotum. Apex obliquely truncate. Humeral angles completely rounded, basal margin conjoined with lateral margin of the elytra in a continuous curve. Sides of elytra gradually arched along their entire length, seemingly continuing their curve also along the margin of the apical truncation, so that the apical external angle is broadly rounded. Sutural angle closely rounded, largely obtuse. Elytra convex, with just the last interval flattened in the posterior half of the elytra. Punctuation present on all elytral surface, denser on the anterior half of disc. Striae 1 to 7 visible along all their length, less engraved at base; 8 th stria absent. Intervals feebly convex. Interval 3 wider than the adjacent ones. Basal seta positioned on stria 1, closer to the suture than to the scutellum. Umbilicate series continuous from base to apex of elytra, composed of 18 points diffi- cult to distinguish due to the sculpture of elytral margin.

Abdomen. Abdomen protruding from the elytra in dorsal view, leaving the last 2 terga visible (the penultimate only to a small extent). Apophysis or dechitinized regions on ventral side absent.

Genitalia. TL of the aedeagus: 1,0 mm. Median lobe of the aedeagus robust, with a rounded apex in lateral view (Fig. 3). Base with a large, globous bulb; median section parallel-sided; at ⅔ of the total length the aedeagus narrows up to the apex. Ventral margin almost rectilinear, slightly sinuous before apex. Dorsal margin linear at the beginning (parallel to the ventral side), then gradually curved downwards. Apex prolonged in a small rounded lobe. The inner sac of the aedeagus has two symmetrical sclerified parts, vaguely elliptical in shape. Parameres as in Fig. 3.

Derivatio nominis: The name “ rotundata ” refers to the combined shape of the elytra of this species, which, in dorsal view and together with the abdomen, assume an almost circular shape (from Latin “ rotundata ”, meaning “rounded”).