Limnichus arabicus, Hernando & Ribera & Csic, 2014

Hernando, Carles, Ribera, Ignacio & Csic, 2014, The Limnichidae (Coleoptera) of the Arabian Peninsula and the island of Socotra, Acta Entomologica Musei Nationalis Pragae 54, pp. 173-189 : 185-187

Limnichus arabicus sp. nov.

( Figs 3 , 14 )

Type locality. Yemen, Al Mahrah Governorate, Al Ghaydah, Jabal al Fattk.

Type material. HOLOTYPE: J ( NMPC), ‘E YEMEN, Jabal al Fattk, / Hawf NE Al Ghaydah, / N16º40ʹ E53º05ʹ, 729 m / 12.-13.X.05, lgt. P.Kabátek’ [genitalia and abdominal ventrites dissected and mounted in DMHF on a transparent card pinned with the specimen; right antennae missing from antennomere III].

Description. Length 1.7 mm, maximum width 1.1 mm. Body shape oval, strongly convex ( Fig. 3 ). Dark brown, all body covered with dense, short, hydrophobic decumbent pubescence; pubescence with golden or silvery reflects depending on setal orientation.

Head. Eyes slightly convex, prominent in dorsal view; with strong border reaching insertion of antennae. Surface of head with supraocular depression, as typical of the Limnichus group of genera. Antennomere I (scape) wider and shorter than II (pedicel), quadrangular in shape; antennomere III narrower than II, shorter; antennomeres V and VI elongate, subparallel, VI slightly shorter than V; antennomere VII very short; antennomeres IX to XI forming a loose club, XI larger and longer, with apex slightly asymmetric. Antenna with two kinds of pubescence, one short and dense, and the other formed by long sparse setae, particularly apparent on club.

Pronotum trapezoidal, very finely bordered on lateral and anterior margin, posterior margin not bordered. Anterior margin regularly concave, posterior margin bisinuate on both sides. With very dense and poorly impressed puncturation uniformly distributed, similar to that on head.

Maximum width of elytra in middle part, apex rounded. With two types of puncturation, one less impressed, similar to that on pronotum, and other formed by larger punctures, well impressed, uniformly distributed on whole surface, with no recognisable striae. Space between punctures larger than their diameter. Metathoracic wings well developed.

Ventral side with strong, dense puncturation; with dense, recumbent pubescence except for metaventrite which is glabrous. Last visible ventrite with semicircular indentation, with glandular pores on whole surface of ventrites III, IV and base of V, except lateral areas. Ventrites I and II connate; with two types of puncturation, one very fine and dense over whole surface, other coarser and less dense in intercoxal area of ventrite I and middle part of II; ventrite I with line of strong punctures bordering depression for reception of legs. Last abdominal ventrite slightly emarginate.

Anterior side of apex of protibia with comb of spines, as typical of the Limnichus group of genera.

Male genitalia ( Fig. 14 ). Aedeagus symmetrical, except phallobase; median lobe as long as parameres and much longer than phallobase, apex acuminate; struts symmetrical, as long as phallobase; apex of parameres with triangular membranous expansions. Base of genital segment slightly asymmetrical; parameres equal in length, elongate; apex of membranous expansion pubescent. Ventrite 8 V-shaped, with apical membranous semicircular expansions; with pubescence in apical margin.

Females unknown.

Etymology. Named after the Arabian Peninsula; adjective.

Distribution ( Fig. 16 ). So far only known from the type locality in continental Yemen.

Remarks. The peculiar shape of the apex of the parameres of the aedeagus is not found in any of the known Afrotropical species of the genus ( DELÈVE 1968). In the description of Limnichus micraspis Champion, 1923 , from northeast India, it is noted that some specimens from Karachi and Fyzabad ( Pakistan) could belong to this species ( CHAMPION 1923). This would be the only known record of Limnichidae from Pakistan. According to the description, L. micraspis seems to be smaller (1.25 mm), with the ventral side rufescens and the appendixes rufo-testaceous ( CHAMPION 1923).

Figures

Figs 1–5. Habitus of the Limnichidae of Arabian Peninsula and Socotra Islands. 1 – Pelochares sinbad sp. nov.; 2 – P. sabaeanus sp. nov.; 3 – Limnichus arabicus sp. nov.; 4 – Byrrhinus socotrensis sp. nov.; 5 – B. helicophallus sp. nov. Upper scale bar applied to Figs 1–3, bottom scale bar to Figs 4–5.

Fig. 14.Male genitalia of the holotype of Limnichus arabicus sp. nov.A – aedeagus; B – genital segment; C – ventrite VIII. Scale bar: 0.5 mm.

Fig. 16. Distribution of the known Arabian Limnichidae. Blue circles – Pelochares sinbad sp. nov.; green circles – P. sabaeanus sp. nov.; red circles – Byrrhinus helicophallus sp. nov.; yellow circles – B. socotrensis sp. nov.; purple circle – Limnichus arabicus sp. nov. With question marks, specimens of uncertain identity from Ethiopia; inset – detailed distribution of B. socotrensis sp. nov. in Socotra.