Clavomicrus, Jałoszyński, 2019

Jałoszyński, Paweł, 2019, ' Genus X 2 ' finally named: discovery of males of Clavomicrus gen. n. in the Philippines (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4564 (1), pp. 289-294 : 290-291

Clavomicrus gen. n.

Type species: Clavomicrus orousseti sp. n. (here designated).

Diagnosis. Antenna composed of ten antennomeres, with conspicuous oval club composed of completely fused antennomeres X and XI; prothorax lacking dorsal glandular openings and internal 'cavities'; pronotum with two pairs of lateral antebasal pits, inner pair connected by transverse groove.

Description. Body ( Figs 1–2 ) suboval, strongly convex, sparsely setose.

Head capsule ( Figs 1–2, 3, 5 ; and Fig. 14B in Jałoszyński (2011b)) short and broad, in intact beetles tilted so strongly that plane of vertex is perpendicular to the long body axis ( Fig. 2 ); frons and vertex confluent, transverse, convex; supraantennal tubercles indistinct; frons with a pair of tiny diffuse tubercles; eyes large, coarsely faceted, strongly convex; gular plate ( Fig. 5 ; gp) large, transverse, with sharply marked gular sutures ( Fig. 5 ; gs) and transverse reticulate microsculpture; posterior tentorial pits indiscernible; submentum ( Fig. 5 ; smn) very short and strongly transverse. Mentum ( Fig. 5 ; mn and Fig. 14F in Jałoszyński (2011b)) subrectangular, transverse; prementum ( Fig. 5 ; pmn) short, with an unknown number of paired suckers, labial palps minute and broadly separated, inserted at sides of prementum, with palpomere I largest, slightly longer than broad, palpomere II much shorter and slightly narrower than I, shorter than broad, palpomere III much narrower and much longer than II, rodlike with narrowed apex, about 2.5 × as long as broad. Maxilla (Fig. 14E in Jałoszyński (2011b)) with triangular basistipes, elongate mediostipes, elongate lacinia and galea, each with sparse and thick mesal setae; elongate palpifer; maxillary palp ( Fig. 5 ; mxp; Fig. 14E in Jałoszyński (2011b)) with minute palpomere I, strongly elongate, clavate palpomere II, strongly broadened palpomere III which is less than twice as long as broad and has truncate apex, palpomere IV broad and very short, button-like. Mandible ( Fig. 5 ; md; Fig. 14D in Jałoszyński (2011b)) short and robust, with subquadrate basal portion and large subtriangular, relatively blunt apical tooth bent mesad at a nearly right angle, setose prostheca absent. Labrum (Fig. 14C in Jałoszyński (2011b)) subrectangular, strongly transverse, with anterior margin straight.

Antennae ( Figs 1–2, 4 ; Fig. 14G in Jałoszyński (2011b)) long and slender, composed of 10 antennomeres, with a composite oval and abruptly delimited club (fused antennomeres X and XI).

Pronotum ( Fig. 3 ) in dorsal view subtrapezoidal with rounded anterior margin, rounded anterior corners which are not visible in dorsal view, shallowly serrate and complete lateral carinae, distinct posterior corners and posterior margin with small median emargination. Pronotal base with two pairs of small lateral antebasal pits ( Fig. 3 ; abp), inner pair connected by transverse groove.

Prosternum ( Fig. 5 ; Fig. 14H in Jałoszyński (2011b)) with basisternal portion much shorter than coxal part; prosternal process ( Fig. 5 ; psp) in ventral view subtriangular, in lateral view (Fig. 14H in Jałoszyński (2011b)) subtriangular with rounded apex, elongate but not expanding ventrad beyond procoxae, slightly bent posterad; notosternal sutures obliterated in front of procoxae; procoxal cavities broadly closed by posterolateral lobes of prosternum that are fused with postcoxal lobes of hypomera; hypomeral ridges ( Fig. 5 ; hyr) complete; hypomera ( Fig. 5 ; hy) outside hypomeral ridges broad and concave.

Mesonotum (Fig. 14J in Jałoszyński (2011b)) subtrapezoidal, with subtriangular, transverse mesoscutellum largely exposed between elytral bases ( Fig. 3 ), scutoscutellar suture present, mesoscutum strongly transverse.

Elytra ( Figs 1–3 ; Fig. 14M in Jałoszyński (2011b)) oval, each with a distinct elongate subhumeral impression, lacking humeral denticle, each elytron with one vestigial asetose basal fovea ( Fig. 3 ; bef), apices of elytra rounded together.

Mesoventrite ( Fig. 6 ; Fig. 14L in Jałoszyński (2011b)) with narrow anterior ridge ( Fig. 6 ; ar); mesoventral intercoxal process ( Fig. 6 ; msvp) very broad but with its median region raised and forming diffuse and relatively narrow longitudinal elevation, posterior margin of mesoventral process concave, posterior arms present, long. Lateral impressions functioning as procoxal rests (Fig. 14; pcr) present, separated at middle and asetose.

Metanotum (Fig. 14K in Jałoszyński (2011b)) largely membranous, with strongly reduced alacristae not reaching middle of metascutum.

Hind wings absent.

Metaventrite ( Fig. 6 ; Fig. 14L in Jałoszyński (2011b)) short and transverse; posterior margins of mesocoxal rests not carinate; sides slightly convergent posterad, posterior margin weakly concave at each metacoxa, with broad and short metaventral intercoxal process ( Fig. 6 ; mtvp) slightly emarginate at middle. Metanepisterna and metepimera narrow.

Metendosternite (= metafurca) (Fig. 14 E in Jałoszyński (2011b)) with very short and broad stalk and divergent lateral furcal arms with adjacent bases (nearly V-shaped).

Legs ( Figs 1–2, 5–6 ) moderately long and slender; pro- and mesocoxae oval, metacoxae strongly transverse; all trochanters short and subtriangular; all femora distinctly clavate; tibiae broadening distally; tarsi moderately slender.

Abdominal sternites ( Fig. 6 ) unmodified, sternite III (i.e., first visible) twice as long as IV.

Aedeagus ( Figs 7–10 ) elongate, with symmetrical median lobe and endophallus, diaphragm present, circular, sub-basal on ventral wall; parameres slender, with apical and subapical setae.

Distribution and composition. Clavomicrus is represented by one species known to occur in Luzon, the Philippines.

Etymology. The name Clavomicrus combines the prefix clavo - derived from the Latin clava (a club) that refers to the antennal structure, with the stem - micrus, to emphasize the similarity to Cephennomicrus . Gender masculine.

Remarks. Among Cephenniini, decamerous antennae with a large, oval club can be found only in Clavomicrus and Trurlia . The new genus differs from Trurlia (among other, minor characters) in the prothorax lacking a pair of large glandular openings on its dorsal surface (present in Trurlia ), the mandibles lacking preapical teeth (two teeth present in Trurlia ), the prosternal process subtriangular in ventral view and lacking an anterior tip (suboval and with its ventral surface flattened in Trurlia , and with a small anterior projection that in the ventral view is visible as an anterior tip projecting in front of the anterior prosternal margin), a much broader mesoventral intercoxal process, smooth posterior margins of mesocoxal rests (sharply carinate in Trurlia ), and one vestigial basal elytral fovea (two distinct foveae in Trurlia ).

Figures

FIGURES 1–5. Clavomicrus orousseti gen. & sp. n. Dorsal (1) and lateral (2) habitus; head, prothorax and elytral base in dorsal view (3); distal portion of right antenna in dorsal view (4); head and prothorax in ventral view (5). Abbreviations: abp, antebasal pit; a8–11, antennomeres VIII–XI; bef, basal elytral pit; gp, gular plate; gs, gular suture; hy, hypomeron; hyr, hypomeral ridge; md, mandible; mn, mentum; pmn, prementum; psp, prosternal process; smn, submentum.

FIGURES 6–10. Clavomicrus orousseti gen. & sp. n. Pterothorax and part of abdomen in ventral view (6); aedeagus in ventral (7, 9) and lateral (8, 10) views. Abbreviations: ar, anterior ridge; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; pcr, procoxal rest.