Webbia, Hopkins, 1915

Sittichaya, Wisut, Smith, Sarah M. & Beaver, Roger A., 2023, New species, taxonomic changes and newly recorded species of Webbia Hopkins, ambrosia beetles from Thailand and neighbouring countries (Coleoptera: Curculionidae: Scolytinae: Xyleborini), Zootaxa 5264 (1), pp. 47-63 : 59-60

Key to species of Webbia recorded from Thailand

1 Upper margins of elytral declivity angularly produced forwards at the suture and armed with 3 triangular denticles. Pronotum only slightly longer than wide. ( Fig. 4 ).................................................... spinosulcata sp. nov.

- Upper margins of elytral declivity not produced forwards...................................................... 2

2 Margin of elytral declivity armed with stout spines or teeth. Posterior part of elytral disc matt, strongly sculptured, with striae strongly impressed and interstriae costate.................................................................. 3

- Margin of elytral declivity carinate or denticulate. Posterior part of elytral disc shining, striae and interstriae usually flat.... 6

3 Margin of elytral declivity with 6 or 7 spines on each side..................................................... 4

- Margin of elytral declivity with at least 9 teeth on each side.................................................... 5

4 Margin of elytral declivity with 6 spines on each side, lacking teeth on interstriae 2, 4 and 5; face of declivity with a single vermiculate ridge on each side and a row of tubercles lateral to it............................. duodecimspinata Schedl

- Margin of elytral declivity with 7 spines on each side, lacking teeth on interstriae 2 and 4; face of declivity with 2 strong, vermiculate ridges on each side.................................................. quatuordecimspinata Sampson

5 Margin of declivity with 13‒15 teeth on each side; declivital face with vermiculate ridge on interstriae 1 strongly raised in middle of declivity, and with 3‒4 rows of tubercles lateral to it............................... trigintispinata Sampson

- Margin of declivity with 9 or 10 teeth on each side; declivital face with a weak ridge on interstriae 1, and with 2 rows of tubercles lateral to it................................................................... dipterocarpi Hopkins

6 Margin of elytral declivity denticulate. Declivital face and/or posterolateral margin or elytral apex with processes, teeth, spines or tubercles.......................................................................................... 7

- Margin of elytral declivity carinate. Declivital face flat, without armature stronger than granules..................... 15

7 Face of elytral declivity with a pair of very prominent, elongate, bifurcate processes in lower half above apical margin..... 8

- Face of elytral declivity without elongate processes, but with shorter, acutely pointed teeth on posterolateral margin, or spines or tubercles on face of declivity......................................................................... 10

8 Apical processes of elytra not strongly widened from base to apex, upper and lower edges subparallel....... pabo Sampson

- Apical processes of elytra strongly widened from base to apex................................................. 9

9 Discal interstriae 1 prolonged into a short spine projecting over declivity. Acute spine at elytral apex arising from second interstriae........................................................................... diversicauda Browne

- Discal interstriae 1 not prolonged into a spine. Acute spine at elytral apex arising from first interstriae...... biformis Browne

10 Posterolateral margin of elytra with a broad, acutely pointed, slightly reflexed tooth on each side. Face of elytral declivity without tubercles or spines............................................................................. 11

- Posterolateral margin of elytra more or less evenly rounded without prominent teeth. Face of elytral declivity with a pair of tubercles or spines................................................................................... 14

11 Teeth on posterolateral margin of elytra large, length greater than width at base ( Fig. 1 )................. aculeata sp. nov.

- Teeth on posterolateral margin of elytra smaller, length less than width at base.................................... 12

12 Strial punctures on face of elytral declivity very coarse, separated by less than their own diameter....... hatanakai Browne

- Strial punctures on face of elytral declivity fine, more widely separated......................................... 13

13 Declivital interstriae each with a single row of granules bearing a short, recumbent, bristle-like seta; striae not impressed. ( Fig. 2 ).................................................................................... granulosa sp. nov.

- Declivital interstriae without granules, smooth, shining; striae impressed.............................. cornuta Schedl

14 Face of elytral declivity with a pair of small, widely separated tubercles on interstriae 1 just above middle. ( Fig. 5A, B )....................................................................................... bituberculata Browne

- Face of elytral declivity with a pair of large spine-like tubercles on interstriae 1, close together on lower part of declivity near apex. ( Fig. 5E, F )........................................................................ suturalis Browne

15 Elytral declivity with a dense covering of semi-recumbent feather-like setae largely concealing granules. ( Fig. 3 ).............................................................................................. planicauda sp. nov.

- Elytral declivity with sparser, simple setae not concealing granules. ( Fig. 5C, D )................... subuculae (Browne)

Figures

FIGURE 1. Webbia aculeata sp. nov. holotype A) dorsal view; B) lateral view; C) postero-lateral view; D) frons; E) venter and antennae; F) declivital face.

FIGURE 2. Webbia granulosa sp. nov. holotype A) dorsal view; B) lateral view; C) postero-lateral view; D) frons; E) head lateral and antenna; F) declivital face.

FIGURE 3. Webbia planicauda sp. nov. holotype A) dorsal view; B) lateral view; C) postero-lateral view; D) frons; E) head lateral and antenna; F) declivital face.

FIGURE 4. Webbia spinosulcata sp. nov. holotype A) dorsal view; B) lateral view; C) postero-lateral view; D) frons; E) head lateral and antennae; F) declivital face.

FIGURE 5. Dorsal and lateral habitus of newly recorded Thai species A, B) Webbia bituberculata (Browne, 1977); C, D) Webbia subuculae (Browne, 1962); E, F) Webbia suturalis Browne, 1955.