Bicarinulodes, Jałoszyński, 2019

Jałoszyński, Paweł, 2019, Taxonomy of the ' Afroeudesis group' of glandulariine ant-like stone beetles (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4612 (2), pp. 205-220 : 214-217

Bicarinulodes gen. n.

Type species: Microscydmus meridensis Franz, 1988 (here designated).

Diagnosis. Body (Fig. 4) moderately stout, distinctly constricted between head and prothorax and between prothorax and elytra. Head ( Fig. 31 ) about as long as broad with short but distinct tempora; tempora, vertex, genae and postgenae lacking thick bristles; occipital constriction about as broad as vertex; submentum lacking lateral sutures; hypostomal ridges present and complete, obliquely running toward posterior tentorial pits where they are not connected; antennae with trimerous club and modified in males (with antennomere VII enlarged and projecting mesad); frons with shallow frontal impression; vertex lacking posteromedian impression; head lacking longitudinal groove and median subtriangular 'platform'; setae on frons and vertex largely symmetrical; maxillary palpomere IV slightly constricted before apex, so that its apical portion is broadened and truncate; pronotum ( Fig. 31 ) broadest distinctly in front of middle, with unusual set of antebasal structures: two broad submedian longitudinal carinulae and two pairs of small lateral pits; lateral and sublateral pronotal carinae absent; thick bristles on sides of pronotum absent; prosternum ( Fig. 33 ) with basisternal part vestigial; prosternal intercoxal process developed as a sharply marked but weakly elevated carina; procoxal cavities closed; notosternal sutures and hypomeral ridges complete; mesoscutel- lum ( Fig. 31 ) largely exposed between elytral bases; mesocoxal rests with diffuse marginal carinae; mesoventral intercoxal process ( Fig. 35 ) carinate and strongly elevated, narrowly separating mesocoxae, with broadened, flattened and smooth posterior portion, well-defined posterior tip and a narrow posteromedian notch; metaventral carinae present; anterior metaventral process present, well-defined, large, not divided into subrectangular anterior and triangular posterior portions, broadly subtriangular; metaventral intercoxal process ( Fig. 35 ) with a pair of long spines separated by a long and narrow notch; each elytron ( Fig. 31 ) with two vestigial asetose foveae; and aedeagus ( Figs 37–40 ) symmetrical with free, slender parameres.

Description. Body (Fig. 4) elongate but not very slender, distinctly constricted between head and prothorax and less so between prothorax and elytra, strongly convex, brown.

Head ( Fig. 31, 33 ) with moderately large eyes; tempora short but distinct, rounded; frons impressed between antennal insertions, lacking longitudinal groove; vertex anteriorly confluent with frons, lacking posteromedian impression; numerous setae on frons and vertex largely symmetrical; gular plate ( Fig. 33 ; gp) subtrapezoidal; posterior tentorial pits ( Fig. 33 ; ptp) in front of transverse impression demarcating 'neck' region ventrally, minute; hypostomal ridges ( Fig. 33 ; hr) complete, reaching level of posterior tentorial pits, not connected; submentum ( Fig. 33 ; smn) lacking lateral sutures. Antennae (Figs 4, 31–32) slender, with distinct trimerous club, in males modified, with antennomere VII ( Fig. 32 ; a7) enlarged and with a mesal subtriangular projection.

Pronotum ( Fig. 31 ) bell-shaped, broadest anterior to middle; lacking lateral and sublateral carinae, with a pair of longitudinal, broad and flattened carinulae ( Fig. 31 ; car) shortly in front of basal margin, and with two pairs of small antebasal lateral pits: inner ( Fig. 31 ; ip) and outer ( Fig. 31 ; op); transverse antebasal groove distinct, broad and diffuse, divided by carinulae into three impressions. Prosternum with vestigial basisternal region ( Figs 33–34 ; bst), prosternal process carinate but weakly elevated ( Fig. 34 ; psp); notosternal sutures ( Figs 33–34 ; nss) complete; hypomeral ridges ( Figs 33–34 : hyr) complete; inner (adcoxal) portion of hypomeron relatively narrow and glabrous, outer portion (confluent with side of pronotum) lacking thick bristles. Procoxal cavities ( Fig. 34 ; pcc) closed.

Mesoventrite with a pair of transverse impressions behind its anterior ridge that function as procoxal rests ( Figs 35–36 ; pcr); mesoventral intercoxal process ( Figs 35–36 ; msvp) carinate, long, strongly elevated, with distinctly broadened posterior portion bearing a median flattened area ( Fig. 35 ; mfa) that is smooth and devoid of setae, posterior tip of process with subtriangular emargination; mesoventrite at each side with deep dorsolateral fovea ( Fig. 36 ; dlf).

Mesoscutellum ( Fig. 31 ; msc) exposed between elytral bases in intact beetles, subtriangular, about as long as broad.

Metaventrite with massive subtrapezoidal anterior metaventral process ( Figs 35–36B ; amtp); each side of metaventrite with metaventral carina ( Figs 35–36 ; mtvc), carinae are parallel to each other; mesocoxal rests very deep and filled with setae, their posterior marginal carina diffuse but complete, postmarginal carina absent; metaventral intercoxal process ( Fig. 35 ; mtvp) with long lateral spines, indistinctly separating metacoxae.

Elytra (Figs 4, 31) oval, each elytron with one pair of vestigial, asetose basal elytral foveae ( Fig. 31 ; bef), lacking basal impression, and with distinct humeral callus. Hind wings developed.

Legs do not differ from other genera of Glandulariini, unmodified in males.

Abdomen unmodified, with sternites III and IV subequal in length.

Aedeagus ( Figs 37–40 ) slender, weakly sclerotized, with symmetrical median lobe and symmetrical, but weakly sclerotized endophallic structures; parameres free, bearing apical setae.

Etymology. The name Bicarinulodes reflects the unique antebasal pronotal carinulae. Gender masculine.

Remarks. Bicarinulodes is more similar to Afroeudesis than to the Meridaphes - Pseudoraphes - Stenichnoconnus group of genera, but it clearly differs from all subgenera of Afroeudesis in the lack of the conspicuous subtriangular and scaly-sculptured 'platform' on the frons and vertex. Bicarinulodes has two autapomorphies, the pair of short, flat submedian carinulae on the pronotal base, and the modified antennomere VII in males. For these reasons, Microscydmus meridensis is not placed in Afroeudesis , but in a separate new genus.

Composition and distribution. Bicarinulodes comprises only its type species known to occur in Venezuela ( Fig. 41 ).

Figures

FIGURE 41. Distribution of 'Afroeudesis group'.

FIGURES 31–34. Morphological structures of Bicarinulodes meridensis (Franz) comb. n., male holotype. Head, prothorax and elytral base in dorsal view (31); antennomeres VI–VIII of right antenna in ventral view (32); head and prothorax in ventral view (33); prothorax in ventral view (34). Abbreviations: a6–8, antennomere 6–8; bef, basal elytral fovea; bst, basisternal portion of prosternum; car, carinulae; gp, gular plate; hr, hypostomal ridge; hyr, hypomeral ridge; ip, inner pit; md, mandible; mn, mentum; msc, mesoscutellum; nss, notosternal suture; op, outer pit; pcc, procoxal cavity; pcr, procoxal rest; psp, prosternal process; ptp, posterior tentorial pit; smn, submentum.

FIGURES 35–40. Morphological structures of Bicarinulodes meridensis (Franz) comb. n., male holotype. Pterothorax in ventral view (35–36); aedeagus in ventral (37, 39) and lateral (38, 40) views. Abbreviations: amtp, anterior metaventral process; dlf, dorsolateral fovea; mfa, median flattened area; msvp, mesoventral intercoxal process; mtvc, metaventral carina; mtvp, metaventral intercoxal process; pcr, procoxal rest.