Pixodarus spiniscapus Bjornstad & Grobbelaar

Bjornstad, Anders, Grobbelaar, Elizabeth & Perissinotto, Renzo, 2016, Review of Afraustraloderesrassei Bouyer, 2012: description of its female and a new species of Pixodarus Fairmaire, 1887 (Coleoptera, Cerambycidae, Prioninae), ZooKeys 558, pp. 77-93 : 82-87

Taxon classification Animalia Coleoptera Cerambycidae

Pixodarus spiniscapus Bjornstad & Grobbelaar sp. n. Figures 5, 6, 7

Type material.

Holotype ♂: SOUTH AFRICA: GAU, Florauna, Pretoria 25°41'20"S, 28°09'30"E, XII.1985, R.H. Watmough (SANC). Paratypes: 1♀: same data as holotype, XI.1989 (SANC); 1♂: same data as holotype, XII.1987 (ABPC); 1♀: RSA, GAU, Magaliesberg, SSW Hekpoort, 25°54'58"S, 27°35'51"E, 21-30.XI.2012, M. Shanahan (SANC).

Material excluded from type series due to insufficient data.

1♂: A69 [no further data] (SANC).

Additional records (iSpot).

1♂: RSA, GAU, Roodepoort, Walter Sisulu National Botanical Garden (26°05'21"S, 27°50'40"E), 05 Nov 2012, A Hankey, http://www.webcitation.org/6ZkmxK0on; 1♀: RSA, GAU, Randburg, Curro Aurora Private School, school grounds (26°04'48"S, 27°56'06"E), 30 Oct 2014, A Hankey, http://www.webcitation.org/6ZknFLtcm; 1♂: RSA, MPU, Presidentsrus (25°45'33"S, 29°19'05"E), 31 Oct 2014, R Bate, light trap, http://www.webcitation.org/6ZknAyhMq; 1♀, ditto, but 14 Nov 2014, http://www.webcitation.org/6ZknGm829.

Description.

Size. Male: 31.5-33.7 mm long, 12.5-13.4 mm wide (maximum width at metacoxae); female: 33.9-34.0 mm long, 13.0-13.7 mm wide (maximum width at metacoxae).

Head. Mandibles black, short and stout with deeply punctate base and strongly hooked apex; maxillary palpi tetramerous, labial palpi trimerous, basal segment of maxillary palpi extremely short and appearing 3-segmented; shape and size of the two types of palpi very similar, both shiny and brown with long, stiff, yellow setae, terminal segments hyaline in apical third and abruptly truncate; frons short, deeply concave, bordered by lateral ridges formed as continuation of mandibular bases; antennal tubercles prominent, separated by a narrow depression which continues well past the eyes posteriorly, then disappears gradually on vertex; yellowish to orange arcuate to curled bristles present on most surface areas, particularly well-developed along above mentioned depression; entire fronto-dorsal surface heavily sculpted with irregular irrorations and foveolations; eyes finely facetted, sinuately emarginate resulting in smaller dorsal eye lobe and larger suborbicular ventral lobe, emargination itself densely pubescent; genae very short.

Antenna. Scape almost wedge-shaped, gradually widening distally from narrow base, slightly compressed, with marked apical spine on proximal side; pedicel very short (<1/5 length of scape); antennomere 4 noticeably shorter than 3 and 5 in male, not in female; antennomeres 3 and 5-10 of subequal length in male; last antennomere longest by far, more than 1.5 times length of preceding; antennomeres 3-9 + 11 of sub equal length in female, only antennomere 10 slightly shorter; antennomeres 1-3 punctate in both male and female, segment 4 transitional and last 7 antennomeres only very finely micropunctate; antennomeres 2-4 practically terete, from segment 5 onwards increasingly flattened and with weak lateral tooth apically; apical segment sharply carinate; antenna reaching approximately 4/5 of elytral length or slightly longer in male, only about ½ or slightly longer in female.

Pronotum. Distinctly transverse, length/width ratio of pronotal disc (lateral spines excluded) approximately 0.6; anterior margin straight to shallowly concave, posterior margin slightly convex medially; three stout spines present laterally on either side, two straight spines at edge of anterior margin and at posterior corner respectively, one strongly curved spine between previous two and pointing posteriorly; few irregular small teeth between first and second spine; pronotal disc irregularly folded and foveate to shallowly vermiculate, elevated parts shiny; sparse yellowish- to rusty brown and somewhat curly pubescence covering much of surface, particularly dense along anterior margin.

Scutellum. Shield-like, pubescent and finely punctate.

Elytron. Dark brown, and rather elongate, ratio elytral length:combined elytral width at metacoxae varying between 1.9 and 2.3; surface distinctly costate, with three costae normally visible at least in part; humeri rounded and weakly marked; posthumeral lateral margin bent outwards and upwards, forming a miniature “gutter”; posterior sutural corner sharply angled, or exhibiting small tooth, otherwise lateral margin evenly rounded; shallow vermiculations in subscutellar part, gradually becoming finely punctate laterally and posteriorly; basal parts sparsely covered with short yellowish pubescence, gradually becoming less conspicuous posteriorly; greatest elytral width in female about half way down the elytron, distinctly wider than in male.

Legs. Profemora with a somewhat scabrid dorsal surface, ventral face punctate; meso- and metafemora smooth and lustrous dorsally; tibiae straight with short rusty brown pubescence, all widening towards the apex, with two short spurs on proximal side and blunt tooth on distal side; all tarsomeres on all legs of subequal length.

Ventral surface. Gula strongly concave and densely punctate in anterior part, transversely undulate in posterior part; prosternum pubescent, distinctly convex with anterior border strongly thickened; prosternal process ligulate with apex bent dorsally; procoxal cavities open; mesosternum punctate and pubescent, very short; mesosternal process short with median furrow, bifurcate apically; metasternum strongly convex, pubescent, finely punctate and glossy; all five visible abdominal sternites of subequal length, finely punctate, pubescent and glossy; last visible sternite with rounded to weakly truncate posterior border in female, weakly concave in male; epipleura well developed in correspondence with dorsal gutter-like extension of elytral margin.

Male genitalia. Median lobe (sensu Ehara 1954, Hubweber and Schmitt 2010; otherwise commonly referred to as just “aedeagus” or “penis”, e.g. Bouyer 2012) with heavily sclerotized acuminate ventral edge of median orifice (= ventral plate sensu Lin and Li 2012, but usually referred to as 'ventral lobe’); dorsal edge of median orifice (dorsal plate/'dorsal lobe’) rounded with emarginate apex, only slightly shorter than ventral edge, and distinctly less sclerotized; basal apophyses (sensu Hubweber and Schmitt 2010; in Ehara 1954 as "median struts") long and strap-shaped, constituting more than 60% of total length of median lobe; median foramen not elongate; tegmen reddish-brown to brown, indicating medium sclerotization ( Hubweber and Schmitt 2006); parameres (lateral lobes) long and slender and widening slightly apically, with brush of setae, shorter than the parameres; pouch-like appendage on internal side at base of each paramere; tegminal ring with converging geniculated arms.

Etymology.

The name ‘spiniscapus’ refers to the prominent apical spine present on the first antennomere or scape.

Remarks.

Pixodarus spiniscapus sp. n. differs from Pixodarus nyassae (Bates, 1878) (syn. Pixodarus exasperatus Quentin and Villiers, 1972) in several diagnostic characters. Unlike Pixodarus nyassae , Pixodarus spiniscapus has costate elytra and these are also more elongate than in Pixodarus nyassae . Its ratio of elytral length: combined width at humeri varies from 1.9 to 2.3, while it ranges between 1.7 and 1.9 in Pixodarus nyassae . The first antennomere, in particular, has a distinct apical spine in Pixodarus spiniscapus , while it is unarmed in Pixodarus nyassae . Furthermore, in Pixodarus spiniscapus most of the pronotal disc and elytral surfaces have a yellowish pubescence, which is lacking in Pixodarus nyassae . The pronotum in Pixodarus spiniscapus has three lateral spines on either side, while there are usually five in Pixodarus nyassae . There are also significant genitalic diagnostics. While the median lobe of Pixodarus spiniscapus is very similar to that of Pixodarus nyassae , the ventral edge of the median orifice (ventral plate) in particular has an acuminate apex longer than that of Pixodarus nyassae . In the terminology of Ehara (1954: 65), that of Pixodarus spiniscapus would classify as 'sharply pointed’ (l.c. Fig. 4), while that of Pixodarus nyassae looks more like 'strongly projected’ (l.c. Fig. 7). The dorsal edge of the median orifice ('dorsal lobe’) in Pixodarus spiniscapus has a more deeply emarginate apex than in Pixodarus nyassae . The tegmen has parameres with setae confined to the widened apical part in Pixodarus spiniscapus , but in Pixodarus nyassae the apical part is not noticeably wider than the basal part, and the setae cover a larger part of the surface.