Alcidodes walliorum Lyal, 2000

Lyal, C. H. C. & Curran, L. M., 2000, Seed-feeding beetles of the weevil tribe Mecysolobini (Insecta: Coleoptera: Curculionidae) developing in seeds of trees in the Dipterocarpaceae, Journal of Natural History 34 (9), pp. 1743-1847 : 1805-1808

Alcidodes walliorum Lyal , n.sp.

Length 3.95±6.65 mm (xÅ5 5.6 mm), PW 5 2.15±3.56 mm (xÅ5 3.1 mm), HW 5 2.65±4.5 mm (xÅ5 3.77 mm) (n 5 23) (®gures 28, 59, 78) .

Head. Rostrum not greatly curved, slightly longer and more slender in female ( RL 5 2.2±3.13 mm, xÅ5 2.61 mm; RL/ PW5 0.80±0.88, xÅ5 0.84; RB/RD 5 0.63±0.85, xÅ5 0.73; n 5 12) (®gure 197) than in male ( RL 5 1.65±2.5 mm, xÅ5 2.25; RL/ PW 5 0.73±0.80, xÅ5 0.77; RB/RD5 0.81±1.04, xÅ5 0.90; n 5 11) (®gure 198); sides divergent towards apex, particularly in female (®gure 17); arising approximately half-way down eye in female, one-third down eye in male .

Thorax. PL/PW 5 0.67±0.74 (xÅ5 0.71, n 5 23); prothorax without tubercle posterior to coxa. Elytra with interstriae weakly wrinkled proximally, strial punctures shallow or deep, generally not as wide as interstriae, humeri with interstria 9 projecting beyond 8 in dorsal view, obscured just posterior to humeri by 8 (®gures 28, 48); EL/HW 5 1.05±1.11 (xÅ5 1.09, n 5 23). Elytra with humeri and anterior and posterior parts of interstriae 3± 6 darker than rest in young specimens, elytra uniformly dark when older; scales mostly hair-like, sometimes broader in transverse band approximately three-quarters of the way down the elytron. Fore femur with ventral tooth subtriangular, lacking proximal lobe, proximal margin at c.90ss to long axis of femur and longer than length of tooth, distal margin dentate or serrate (®gures 135, 160, 161); fore tibia with small ventral tooth, mid and hind tibiae lacking ventral tooth, although there may be a small obtuse elevation. Metasternum strongly produced posteroventrally before hind coxae, its ventral margin strongly diverging from elytral margin.

Abdomen. Ventrite 5 with two caudal setal tufts, those of male larger than those of female; depressed medially, depression broader in female than male (®gures 104, 105).

Male terminalia. Tergite 7 as in ®gure 306; short row of plectral tubercles on each side. Segment 8 as ®gure 307. Genitalia as in ®gures 308±313. Tegmen with parameres fused at base (®gure 309). Aedeagus with apex sub-acuminate, sides converging from base and then subparallel for most of length, AL:AW5 3.57 (®gure 311), distance from ostium to apex subequal to width of ostium (®gure 312).

Female terminalia. (®gures 314±316) Tergite 7 with diagonal row of 5±6 plectral tubercles on either side of midline (®gure 314). Tergite 8 with very weakly rounded posterior margin, disc and median anterior margin relatively weakly sclerotized (®gure 315). Spiculum ventrale (®gure 316) with broad part in same plane as its apodeme when viewed from the side; broad part and apodeme subequal in length; posterior`arms’ narrow, subparallel. Female genitalia as in ®gures 317±320; hemisternites shorter than broad part of spiculum ventrale; vagina tubular, lacking paired lobes near junction with common oviduct (®gures 317±318). Spermathecal duct arising on bursa away from junction with oviduct; spermatheca with gland lobe tubular, very weakly bulbous, straight.

Distinguishing features. Alcidodes walliorum belongs to the crassus subgroup with a steep distal margin to the fore femoral tooth. Within that subgroup it can be distinguished from humeralis and toyi by its generally smaller size and more robust form.

Alcidodes walliorum is one of six morphologically similar species feeding on the seeds of Hopea species. Three of these ( hopeae , gonzoi and sterryorum ) are in the dipterocarpi group, while the other three ( fugitus , walliorum and confusus ) are in the crassus group. The last three species can be distinguished from the ®rst three by the following external characters: (1) the femoral tooth is a single spike, as in other members of the crassus group (®gure 135), and lacks the proximal lobe of species in the dipterocarpi group (®gure 138), although the proximal lobe in both hopeae and gonzoi can be very close to the femoral surface and di cult to see; (2) the elytral punctures are markedly larger and deeper than in hopeae , gonzoi or sterryorum ; (3) the ventral margin of the metasternum diverges strongly from the elytral margin in confusus , walliorum and fugitus (®gure 12), but not in the other three; (4) both sexes have tufts of scales near (and projecting beyond) the posterior margin of ventrite 5 (®gures 104, 105), which are not found in the dipterocarpi group species.

The three species confusus , walliorum and fugitus are very close morphologically. Alcidodes fugitus may be separated most simply by examination of the head pro®le; the rostrum meets the head much closer to the top of the eye in fugitus than it does in either of the other two species (®gures 197, 198, cf. ®gures 199±202) (some care must be taken in using this character, since in all three species the rostrum meets the head higher in the male than in the female). Two other characters are: (1) A. walliorum and A. confusus have smaller elytral punctures than fugitus , which do not interfere with the interstriae as they do in the last species (®gures 59, 69 and 61 respectively); (2) the aedeagi of the three species are very diOEerent in shape (®gures 311, 324, 338 respectively). The last character should always be used to con®rm identity. Distinguishing between A. walliorum and A. confusus is very di cult without dissection (males have, so far, not been reliably separated on external characters), and as these species occur together on individual trees specimens should be dissected. On external characters females of walliorum have the rostrum ¯ared apically in dorsal view to a greater extent than do female confusus , in which the rostrum is more cylindrical (®gures 17, 18). Internally, the aedeagus is fairly uniformly narrow in walliorum (®gure 311) and strongly broadened basally in confusus (®gure 324), while the female spiculum ventrale has the posterior`arms’ narrow and subparallel in walliorum (®gure 316), broader and convergent in confusus (®gure 329), and the vagina has a pair of lobes near the junction with the common oviduct in confusus (®gure 332) which are absent in walliorum (®gure 318).

Etymology. The species is named after Ann, Caroline, Victoria and David Wall of St Albans, UK.

Specimens examined

HOLOTYPE, l Malaysia: Sarawak: with labels:`Holo-/ type’ and`Quop, / W. Sarawak. / March± April 1914 / G.E. Bryant.’ and`G. Bryant Coll. / 1919±147’ and`’l and`303’ and`Dissection / S1 #1’ and` HOLOTYPE / Alcidodes / walliorum Lyal / Lyal det. 1997’ ( BMNH)

PARATYPES: Malaysia: Borneo : Sarawak: 1m, same data but April 1914 , 1m, same data but 10 March 1914 ( BMNH) .

Indonesia: Borneo: Kalimantan, Gunung Palung National Park, Cabang Panti Research Station (1ss15¾S 110ss05¾E), i± iv.1991 (Curran), reared from seeds of: Hopea dyeri (3 ll, 7mm), Hopea mengarawan (8 ll, 4mm) ( MZB, BMNH, UMMZ).

Range. Borneo.

Hosts. Hopea dyeri Heim. , H. mengarawan Miq.