Cephennomicrus lawrencei, Jałoszyński, Paweł, 2017

Jałoszyński, Paweł, 2017, First record of Cephenniini on Christmas Island, with updated checklist of world Cephennomicrus species and summary of their distribution (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4227 (4), pp. 593-600 : 594-596

Cephennomicrus lawrencei sp. n.

( Figs 1–9 )

Type material. Holotype: AUSTRALIA ( CHRISTMAS ISLAND): ♂, five labels: " CHRISTMAS ISLAND / 10.29S 105.33E / Hughs (No.2) Dale / 12, 25 Apr. 1989 / J.F.Lawrence " 'white, printed], " Berlesate / ANIC 1094 / leaf&log litter" [white, printed], "A. N. I. C. / COLEOPTERA / Voucher No. / 87-0177" [green, printed], " ANIC / Specimen " [green, printed]; " Cephennomicrus / lawrencei m. / det. P. Jałoszyński, '16 / HOLOTYPUS " [red, printed] ( ANIC) . Paratype: ♀, same data as holotype except " 10.33S 105.39E, 3 km N South Point, 22 April 1989, ANIC 1101 , under bark & log litter" ( ANIC) .

Diagnosis. BL about 0.7 mm; frons in male with one pair of weakly elevated, tiny submedian tubercles; each supraantennal tubercle with small circular pit at mesal margin; pronotum with four antebasal pits, inner pair connected by shallow transverse groove; head, pronotum and elytra with dense and very short, recumbent setae, lacking macrosetae; aedeagus with looped flagellum and elongate, subtriangular apex.

Description. BL 0.73 mm. Body of male ( Figs 1–2 ) elongate and strongly convex, light brown, covered with yellowish setae.

Head broadest at large, strongly convex and coarsely faceted eyes, HL 0.08 mm, HW 0.18 mm; vertex weakly convex; frons between eyes weakly transversely impressed, with a pair of small and weakly elevated submedian tubercles ( Fig. 2 ); supraantennal tubercles feebly marked, each with distinct, circular pit at mesal margin, pits have slightly diffused or rounded margins. Punctures on head dorsum fine and inconspicuous; setae very short, barely discernible under magnification 80×. Antennae slender and with club composed of enlarged antennomeres IX–XI, AnL 0.30 mm, antennomeres I–II elongate; III slightly transverse, IV–VII each slightly elongate, VIII–X each about as long as broad, XI about as long as IX–X combined, slightly less than twice as long as broad, nearly symmetrical.

Pronotum ( Figs 1–2 ) subrectangular, broadest near anterior fourth; PL 0.24 mm, PW 0.26 mm; anterior margin in strictly dorsal view ( Fig. 2 ) weakly rounded; anterior pronotal corners obtuse-angled and rounded; sides slightly sinuate, broadly and shallowly constricted behind middle; posterior corners obtuse-angled and blunt; posterior margin arcuate; base with two lateral pairs of shallow but distinct pits, inner pair connected by shallow transverse groove. Punctures on pronotal disc fine and inconspicuous; setae very short and dense, nearly recumbent.

Elytra oval, broadest near anterior third; EL 0.41 mm, EW 0.33 mm, EI 1.27; humeral calli distinct, elongate. Punctures on elytra deeper and denser than those on pronotum but very shallow and diffused; setae similar to those on pronotum.

Legs moderately long and slender, unmodified.

Aedeagus ( Figs 3–7 ) in ventral view drop-shaped, elongate; AeL 0.20 mm; median lobe with gradually narrowed, subtriangular and elongate apex, in lateral view slightly bent dorsally; endophallus with long and looped flagellum, in ventral view loops flanked by symmetrical elongate sclerites; parameres slender, in lateral view distinctly broadened in subapical region, each with two long apical setae.

Female. Differs from male only in unmodified, evenly convex frons and vertex.

Distribution ( Figs 8–9 ). External territory of the Commonwealth of Australia: southern part of Christmas Island.

Etymology. The name of this species is dedicated to its collector, the renowned coleopterist John F. Lawrence.

Remarks. The modifications of head in male and structures of the aedeagus are unique for this interesting species. There are only several Cephennomicrus spp. with darkly sclerotized, well-visible and long flagellum: C. fesumatranus Jałoszyński, 2010b (Sumatra) , C. clypeatus Jałoszyński, 2010a (Luzon) , C. lasios Jałoszyński, 2010a (Luzon) , six species of the taiwanensis group (Ryukyus and Taiwan), C. minimus Franz, 1983 ( Sri Lanka), and C. pinguis Jałoszyński, 2009b ( Sri Lanka). In C. fesumatranus , which resembles C. lawrencei also in a similar body shape and extremely short setae on the head, pronotum and elytra, the apical portion of the aedeagal median lobe is rapidly narrowed (vs. gradually narrowed in C. lawrencei ) and the parameres in ventral view are very broad, each with one apical and one subapical seta (very narrow and with two apical setae in C. lawrencei ); C. clypeatus has narrowly constricted, modified clypeus, lacks submedian frontal tubercles and its aedeagus has a broad and emarginated apex (narrowly subtriangular in C. lawrencei ); C. lasios and all members of the taiwanensis species group have extremely elongate, slender aedeagi, at least 3–4 times as long as broad; C. minimus is only 0.62 mm long and more slender than C. lawrencei , its head has a pair of curved grooves extending from the posteromesal margin of each eye toward frons, and its aedeagus has strongly asymmetrical internal sclerotized structures; C. pinguis has distinct, bulging, cushion-like tempora (a character suggested to justify a placement of the pinguis group of species in a separate genus; see Jałoszyński (2011)) and a much broader body, with semicircular pronotum covered with large and deep punctures, its aedeagus does not have any symmetrical components in the endophallus. Cephennomicrus lawrencei resembles also members of the nomurai species group (Ryukyus and Taiwan) in the pair of elongate lateral sclerites of the endophallus; however, all species of the nomurai group have a unique median longitudinal groove on the pronotum ( Jałoszyński 2009a), lacking in C. lawrencei .

The coordinates listed on labels, i.e., 10.29S 105.33E for the holotype and 10.33S 105.39E for the paratype, are in fact 10°29'S 105°33'E and 10°33'S 105°39'E.

Figures

FIGURES 1 – 7. Cephennomicrus lawrencei sp. n., holotype male; dorsal habitus (1); pronotum and head in dorsal view (2); aedeagus in ventral (3, 5) and lateral (4, 7) views; details of flagellum and lateral sclerites in ventral view (6).

FIGURES 8 – 9. Distribution of Cephennomicrus lawrencei sp. n. within Sundaland (8) and Christmas Island (9).