Genyocerus species

Beaver, R. A. & L. - Y, 2007, A review of the genus Genyocerus Motschulsky (Coleoptera: Curculionidae: Platypodinae), with new synonyms and keys to species, Zootaxa 1576 (1), pp. 25-56 : 28-30

Key to Genyocerus species , males

1 Apical margin of fourth ventrite extended as a hyaline membranous structure projecting over basal part of concavity of fifth ventrite ( Fig. 12 ). Apex of elytral disc with 5 teeth on each side, the teeth usually flattened, short and blunt, truncate or weakly bifid, but slender and acute in G.shoreae .................................2 – Apical margin of fourth ventrite not membranous nor extending well beyond basal margin of fifth. Apex of elytral disc either with 4 long slender, acutely pointed spines on each side ( Fig. 6 ), the posterolateral angles of the elytra sometimes armed with a fifth spine, or with 2 well-defined teeth on interstriae 3 and 5, and interstriae 7–9 fused to form a common plate with an acute edge ( Figs 26, 27 ), which may project as a tooth on interstriae 7 and may bear several other minute teeth..................................................................10

2 Elytral teeth long, triangular, acutely tipped. Pronotum with one mycangial pore on either side of midline. Fifth ventrite shining, impunctate. 5.4 mm long. Philippines only .............................. G. shoreae Browne

− Inner elytral teeth shorter, truncate, bluntly rounded or more or less bifid. Pronotum with various numbers of pores, usually more than one on each side. Fifth ventrite usually with appressed hairs or scales..3

3 Concavity of fifth ventrite with scattered, long, erect hairs, denser towards sides, curving towards the middle of the concavity, without a dense covering of scale-like hairs. Pronotum with 1–3 mycangial pores on each side. First tooth at elytral apex truncate, the second wider than the first, second to fourth teeth progressively more narrowly rounded, fifth tooth tapering to apex ( Fig. 1 ). 4.0– 4.6 mm long ......................... ........................................................................................................................................ G. biporus (Schedl)

− Concavity of fifth ventrite densely punctulate, the punctures with short, appressed hairs, sometimes flattened and scale-like, directed towards apex, long erect hairs present only around edges of ventrite. Pronotum with 0–c.40 pores on each side. Arrangement of elytral teeth not exactly as alternate........................4

4 Larger species, at least 4.3 mm long. First to fourth elytral teeth bifid with concave apical margin ( Fig. 15 ). Pronotum with 4–9 or 12–16 pores on each side.................................................................................5

– Smaller species, less than 4.0 mm long. First and second teeth usually truncate or almost so, at most weakly bifid apically, third and fourth teeth truncate or rounded. Pronotum usually with 1–3 pores on each side (up to 5 in G. talurae )....................................................................................................................6

5 Elytral teeth narrow, much longer than wide, strongly tapering, each tooth well separated from the next by a V-shaped emargination ( Fig. 15 ). Pronotum with 12 – 16 mycangial pores on each side. Malaysia, Philippines........................................................................................................................ G. multiporus (Schedl)

– Elytral teeth broad, at least first and second teeth wider than long, not strongly tapering, the teeth narrowly separated ( Fig. 19 ). Pronotum with 4 - 9 pores on each side. New Guinea.............. G. papuanus Roberts

6 Pronotum about as wide or slightly wider than long ( Fig. 11 ). Elytra with striae 3–5 clearly impressed, and more coarsely punctured. Concavity of fifth ventrite matt, densely covered by minute, appressed scales ..................................................................................................................... G. frontalis (Strohmeyer)

− Pronotum about 1.2–1.3 times longer than wide. Elytral striae not impressed on disc, more finely punctured. Fifth ventrite matt or subnitid with appressed hairs, which are longer than broad............................7

7 Concavity of fifth ventrite without a longitudinal elevation. 2.5–2.9 mm long..........................................8

– Concavity of fifth ventrite with a longitudinal elevation in either basal or apical half. 2.7–3.4 mm long...9

8 Lower half of frons without a median or lateral carinae. Pronotum with one pore on each side. Inner three teeth on elytral apex truncate, the first much shorter than teeth 2–3, which are subequal. Sri Lanka only ............................................................................................................................. G. albipennis Motschulsky

– Lower half of frons with a median carina, and on each side of this a short vertical ridge or carina. Pronotum either without pores or with 1–3 on each side. Elytral teeth usually tapering, with at least the inner two teeth bifid, but occasionally nearly parallel-sided, subtruncate, the first tooth not much shorter than teeth 2–3 ( Fig. 8 ). India, Southeast Asia to Borneo and Philippines, but not known from Sri Lanka.......... ................................................................................................................................... G. diaphanus (Schedl)

9 Pronotum with 1–5 pores on each side of median line. Inner four teeth on elytral apex truncate. Concavity of fifth ventrite with a median longitudinal elevation in apical half, subnitid. India to Vietnam............ ...................................................................................................................................... G. talurae (Stebbing)

– Pronotum usually without pores, occasionally with 1 pore on one or both sides. Inner two teeth on elytral apex subtruncate, at least the second with minute teeth apically, third and fourth teeth rounded apically ( Fig. 32 ). Concavity of fifth ventrite weakly or moderately elevated in middle in basal half, matt. Malaysia and Indonesia.................................................................................................. G. serratus (Schedl)

10 Apex of elytral disc with separate teeth on interstriae 3 and 5, but interstriae 7–9 fused to form a common plate with an acute edge ( Fig. 27 ), which may project as a third tooth on interstriae 7 and may bear several other minute teeth. Declivity narrow, sulcate, with a spine (usually small, but almost as long as the teeth on interstriae 3 and 5 in exilis ) below the end of interstriae 4–5................................................................11

− Apex of elytral disc with 4 or 5 well-defined teeth of approximately equal size, lateral interstriae not fused near apex to form a common plate ( Fig. 6 ). Declivity without a spine below the end of interstriae 4 - 5, the declivity often extremely narrow or obsolescent..................................................................................14

11 Pronotum with 30–40 large pores on each side of median line. Teeth on interstriae 3 and 5 pointed ( Fig. 23 ). New Guinea only ......................................................................................................... G. puer (Schedl)

– Pronotum with 0–3 large pores on each side of median line. Teeth on interstriae 3 and 5 either bifid at tip, or truncate or nearly so. Occurring outside New Guinea......................................... 12

12 Pronotum with a single large pore on each side of median line, and lateral to these a group of 5–13 smaller pores. Occasionally the large pores may be absent. Teeth on interstriae 3 and usually those on interstriae 5 bifid at apex ( Fig. 9 ). Declivital spine below the end of interstriae 4 large, almost as long as teeth on interstriae 3 and 5. Several minute, acutely pointed teeth on apical margin of fused interstriae 7–9. 1.8– 2.0 mm long ........................................................................................................................ G. exilis (Schedl)

– Pronotum without a group of small pores lateral to the 1–3 large pores. Interstrial teeth usually more or less truncate. Declivital spine below the end of interstriae 4 small, much shorter than the interstrial teeth. Apical margin of fused interstriae 7–9 without a series of minute, acutely pointed teeth. 2.1–3.2 mm long....................................................................................................................................................................13

13 First tooth on elytral apex as wide as second, almost parallel–sided, truncate or bluntly rounded at tip ( Fig. 26 ). Surface of fifth abdominal ventrite irregularly rugulose. Larger species, 2.5–3.2 mm long ................ ................................................................................................................................. G. quadriporus (Schedl)

– First tooth on elytral apex narrower than second, tapering to weakly bifid tip ( Fig. 37 ). Surface of fifth abdominal ventrite longitudinally rugulose. Smaller species, 2.1–2.3 mm long .......... G. tenellus (Schedl)

14 Second spine much shorter than first and third. Posterolateral angles of elytra with a spine similar in length to spine on interstriae 9....................................................................................................................15

– Second spine almost equal in length to first and third. Posterolateral angles of elytra without a long, acute spine similar in length to spine on interstriae 9, with or without a much shorter, small tooth...................16

15 First and third spines about twice as long as second and fourth. Body larger, 3.3–3.6 mm long.................. ...................................................................................................................................... G. spinatus (Browne)

– First and third spines less than twice as long as second and fourth. Body smaller, 2.7–3.1 mm long .......... ................................................................................................................................. G. pendleburyi (Schedl)

16 Elytra clearly narrowed posteriorly. Third spine longer than first, slightly incurved, without a secondary tooth on its outer margin ( Fig. 6 ). Posterolateral angles of elytra without a tooth. Pronotum usually with a patch of small pores lateral to the single large pore on each side of the median line. Smaller species, 2.6 –2.8 mm long ........................................................................................................... G. borneensis (Browne)

– Elytra not narrowed posteriorly. Third spine shorter than first, not incurved, with a small secondary tooth on its outer edge (Fig.30). Posterolateral angles of elytra with a small tooth. Pronotum never with a patch of small pores lateral to the single large pore on each side of the median line. Larger species, 3.3–3.6 mm long .................................................................................................................... G. quadrispinosus (Schedl)

Figures

PLATE 1. FIGURE 1. Genyocerus biporus (Schedl) dorsal view of male. FIGURE 2. Genyocerus biporus (Schedl) dorsal view of female. FIGURE 3. Genyocerus biporus (Schedl) frontal view of female head. FIGURE 4. Genyocerus biporus (Schedl) lateral view of male head.

PLATE 2. FIGURE 5. Genyocerus borneensis (Browne) dorsal view of male. FIGURE 6. Genyocerus borneensis (Browne) lateral view of male elytra. FIGURE 7. Genyocerus borneensis (Browne) fronto–dorsal view of female head.

PLATE 3. FIGURE 8. Genyocerus diaphanus (Schedl) dorsal view of male. FIGURE 9. Genyocerus exilis (Schedl) lateral view of male elytra. FIGURE 10. Genyocerus exilis (Schedl) lateral view of female head.

PLATE 4. FIGURE 11. Genyocerus frontalis (Strohmeyer) dorsal view of male. FIGURE 12. Genyocerus frontalis (Strohmeyer) lateral view of elytra, showing membranous extension of apical margin of fourth abdominal ventrite. FIG- URE 13. Genyocerus frontalis (Strohmeyer) dorsal view of female head. FIGURE 14. Genyocerus frontalis (Strohmeyer) lateral view of female head.

PLATE 5. FIGURE 15. Genyocerus multiporus (Schedl) dorsal view of male. FIGURE 16. Genyocerus multiporus (Schedl) dorsal view of head and pronotum of female. FIGURE 17. Genyocerus multiporus (Schedl) lateral view of female head. FIGURE 18. Genyocerus multiporus (Schedl) frontal view of female head.

PLATE 6. FIGURE 19. Genyocerus papuanus Roberts

PLATE 7. FIGURE 23. Genyocerus puer (Schedl) dorsal view of male. FIGURE 24. Genyocerus puer (Schedl) dorsal view of female. FIGURE 25. Genyocerus puer (Schedl) lateral view of head of female.

PLATE 8. FIGURE 26. Genyocerus quadriporus (Schedl) dorsal view of male elytra. FIGURE 27. Genyocerus quadriporus (Schedl) lateral view of male elytra. FIGURE 28. Genyocerus quadriporus (Schedl) dorsal view of female.

PLATE 10. FIGURE 32. Genyocerus serratus (Schedl) dorsal view of male. FIGURE 33. Genyocerus serratus (Schedl) dorsal view of head and pronotum of female. FIGURE 34. Genyocerus serratus (Schedl) lateral view of head of female.

PLATE 12. FIGURE 37. Genyocerus tenellus (Schedl) dorsal view of male. FIGURE 38. Genyocerus tenellus (Schedl) dorsal view of female. FIGURE 39. Genyocerus tenellus (Schedl) lateral view of female head.