Baiocis incisus (Sampson)

Beaver, Roger A., 2018, A review of the genus Baiocis Browne, 1962 (Coleoptera: Curculionidae: Platypodinae), with new species, new synonymy and a key to males, Zootaxa 4434 (3), pp. 481-501 : 494-495

Baiocis incisus (Sampson)

( Figs 7‒8 )

Crossotarsus incisus Sampson, 1927: 1 .

Baiocis incisus (Sampson) : Browne 1962: 651.

Taxonomy: When he described this species, Sampson (1927) gave no indication of where type material was deposited. Schedl (1941) noted that he had borrowed a 'cotype’ from the Naturhistoriska Riksmuseum in Stockholm (SMNH), and that he had prepared a more detailed description for publication. This redescription was never published. Wood and Bright (1992) state that the male holotype is in BMNH. However, this is incorrect. The BMNH collections contain one male, and one female (lacking both elytra) from the Sampson collection, which appear to be from the type series from Sibajak volcano in Sumatra ( Indonesia), but are not labelled as types. The female has been misdetermined by Schedl as Platypus perinimicus Schedl.

SMNH holds one male and one female syntypes. The male bears the following four labels: Sibajak / vulcan// Sumatra:/ Mjoeberg // incisus Samps. / Type // Typus. The female has the same upper three labels, but the lowest label : Allotypus. Both are in good condition. To ensure correct and consistent application of the name, we here designate the male in SMNH as the lectotype of Crossotarsus incisus Sampson. The female automatically becomes a paralectotype. The species is apparently known only from the type material collected in Indonesia (Sumatra). Because Sampson's (1927) original description is brief, and omits important characters, both male and female are redescribed below from the lectotype and paralectotype ( SMNH) .

Male: 2.65 mm long, 4.7 times as long as wide, brown, elytra lighter than head and pronotum. Head with frons flat, shining, not rugulose, sparsely, moderately finely punctured, the punctures with long, erect hairs, dorsally directed on upper part of frons; median striga extends over middle third of frons; frons rounded into vertex, which is weakly strigose with a fingerprint-like pattern, and with a transverse row of four coarser punctures bearing long, erect hairs anteriorly. Pronotum 1.44 times as long as wide, lateral emarginations deep, angulate anteriorly, with a short carina at the upper margin, broadest just behind the emarginations, shining, almost impunctate, strigillose, median line extending anteriorly to level of middle of emargination. Elytra 2.8 times as long as wide, just under twice as long as pronotum, horizontal, narrower than pronotum anteriorly, sides very weakly convex, widest about 0.6 of length from base, then more strongly incurved, the posterolateral margins with a series of 7-8 small, triangular teeth, elytral surface smooth, except apically, where the posterolateral areas are granulate-punctate; striae and interstriae with fine punctures, larger posteriorly, but obsolescent both near the base and just anterior to the apex, glabrous except at the lateral margins which bear a row of hairs, and on the posterolateral granulate-punctate areas where the punctures bear short hairs. Elytral apex with a moderately deep, broad, U-shaped emargination between short, slightly downturned posterolateral processes. Elytral declivity vertical, very shallow, lunate, without a carina at the upper margin. Abdomen with first ventrite with a median, tabular, truncate process extending over the second ventrite, which bears two small rounded processes separated by about the width of the process on the first ventrite. Metanepisternum with a small tubercle at anterior margin of metasternal-metepisternal depressed area.

Female: 2.7 mm long, five times as long as wide, generally resembling the male, but the frons weakly impressed between the antennal insertions, slightly transversely rugulose on the upper part, and more angularly rounded into the vertex. Pronotum as in male, without mycangial pores. Elytra lacking teeth on the posterolateral margin, and the apex without a U-shaped emargination, simply punctate posterolaterally. Elytral declivity vertical, weakly transversely concave, about 7-8 times as wide as deep across both elytra, and with a dense fringe of yellow hairs extending beyond the elytra apex. Abdomen without processes on ventrites 1 and 2.

Distribution: Indonesia (Sumatra) only.

Biology: Unknown.

Figures

FIGURES 1–9. Baiocis species males. 1‒3. B. crassiventris. 1, dorsal view; 2, lateral view head; 3, lateral view elytral apex. 4. B. anaticeps, lateral view elytral apex. 5‒6. B. perinimicus, elytral apex. 5, posterolateral view; 6, lateral view. 7‒8. B. incisus. 7, dorsal view elytral apex; 8, ventral view abdomen. 9. B. spiniventris, ventral view abdomen. Scale line = 1.0 mm (Fig. 1); 0.5 mm (Figs 2‒6, 9); 0.67 mm (Figs 7‒8).