Tylodinus cavicrus, Champion, 1905

Luna-Cozar, Jesús, Anderson, Robert S., Jones, Robert W. & León-Cortés, Jorge L., 2014, A taxonomic monograph of the genus Tylodinus Champion (Coleoptera: Curculionidae: Cryptorhynchinae: Tylodina) of Chiapas, Mexico, Zootaxa 3788 (1), pp. 1-63 : 18

Tylodinus cavicrus species group

Recognition. This species group is distinguished by the shape of the front and middle tibiae, which are bowed inwards at the apex, acutely dentate on the inner side beyond the middle, the space between this and the tip being very deeply excavate ( Figure 27 ); this form of the legs is more distinct in males than in females.

Diagnosis. Body 2.0–2.3x longer than wide, black, head and rostrum reddish in some specimens. Head with dark brown scales; with patch of overlapping scales on middle of vertex, whitish, yellow or light brown; frons moderately concave or concave (one species); rostrum moderately robust, rugulate (one species), moderately convex, punctures small and deep, moderately dense, size similar to punctures on head, apical area puncticulate; eyes moderately convex. Pronotum in lateral view moderately or strongly convex (one species), outline with anterior and posterior constriction, these constrictions moderately to strongly depressed ( Figure 11 ); in dorsal view with sides slightly divergent from base to midlength, then convergent to apex, constricted beyond the middle ( Figures 14 ), with longitudinal and moderately deep impression; surface granulate, moderately carinate and/or rugose (one species); punctures contiguous or dense on lateral sides, progressively more spaced, smaller and shallower to the median section, and less conspicuous to the anterior and posterior section ( Figure 15 ); with yellow or light brown scales very dense on lateral sides and flanks, anterior area forming a thick longitudinal fringe along the middle and a narrow strip that diverges from the middle base to the flanks, and with dark brown scales on the middle and posterior areas of the disc. Elytra black; with basal margin moderately to slightly sinuate (one species) ( Figures 3–4 ); surface granulate, denser on tubercles; striae 10 complete; elytral scales sparse to moderately dense, dense at base and half of the disc, becoming more separated towards flanks, very dense at intervals of 1–2 of the elytral declivity; tubercles in I2 on declivity smaller than tubercle in I 4 in same position or same size (one species). Metasternum with median section concave, smooth and glabrous; metasternal tooth present or absent (one species). Male abdomen with ventrites 1–2 not in the same plane as ventrites 2–5; ventrite 1 concave or moderately concave (one species), median section posteriorly smooth and glabrous; ventrite 2 longer than ventrites 3–4 combined, slightly concave, with two transverse lines of scales interrupted medially ( Figure 23 ); ventrite 5 as large as ventrite 1, convex or flat in middle (one species), with an impression at anterior middle. Legs with dense scales, femora armed, hind femur almost reaching the elytral apex, front and middle tibiae (especially of male) bent inwards apically, sharply toothed on inner margin beyond middle, the space between tooth and apex deeply excavate ( Figure 27 ); hind tibia with outer margin straight or with external tooth, premucro absent. Male genitalia ( Figures 101–103 ) with median lobe in lateral view stout (one species) or moderately stout, weakly curved; in ventral view as long as half-length of apodemes (one species) or equal to apodeme length, lateral sides straight, subparallel, apex truncate or blunt ( Figures 98c , 103 ); apical process in lateral view weakly curved, not curved downward, in ventral view constricted beyond the median orifice, sides subparallel; tergite eight longer than width; sternite eight elongate. Female genitalia with the apex of the tergite eight straight, trapezoidal, the margin of apex smooth and slightly curved; spermatheca very shallowly curved, outer margin not convex to slightly convex, ramus slender and short, nodulus slender.

Key to species of Tylodinus cavicrus species group

1 Tubercle on interval 2 of elytral declivity with a distinct patch of yellow to light brown scales ( Figures 38–39 ); hind tibia with an external tooth ( Figure 26 )............................................................ T. rugosus Luna-Cozar

- Elytra without patches of scales on tubercles on declivity; hind tibia without an external tooth......................... 2

2(1) Elytral declivity with the tubercle on interval 4 distinctly larger than the tubercle on interval 2 ( Figures 34–35 )............................................................................................... T. cavicrus Champion

- Elytral declivity with the tubercle on interval 4 slightly larger than the tubercle on interval 2 ( Figures 36–37 )........................................................................................... T. pseudocavicrus Luna-Cozar

Figures

FIGURES 20–27. 20–21. Tylodinus spiniventris: 20. meso- and metathorax (male) 21. ventrite 5 (female), 22. Tylodinus elongatus ventrite 5 (female), 23. Tylodinus triumforium, ventrite 2 (male). 24. Tylodinus complicatus, ventrite 2 (female). 25. Tylodinus complicatus, ventrite 2 (male), 26. Hind tibia of Tylodinus triumforium, 27. Front tibia of Tylodinus rugosus.

FIGURES 1–11. 1–5. Dorsal outline: 1. Generalized Tylodinus, indicating terminology used in this study. Key: letters indicate areas of pronotum. A, anterior area; B, median area; C, posterior area; a, anterior of lateral area; b, median section of lateral area; c, median section of dorsal area; d, anterior section of dorsal area; e, posterior section of lateral area; f, posterior section of dorsal area. 2. Tylodinus variabilis, note elytra basal margin straight. 3. Tylodinus ixchel, note elytra basal margin slightly sinuate. 4. Tylodinus immundus, note elytral basal margin sinuate. 5. Tylodinus elongatus, note elytra basal margin very sinuate. 6–11. Lateral outline: 6. Tylodinus complicatus, male, note ventrites 3–5 in same plane as ventrites 1–2. 7. Tylodinus variabilis, male, note ventrites 3–5 not in same plane as ventrites 1–2. 8. Tylodinus coapillensis, female, note ventrites 1–2 strongly convex, ventrites 3–5 not in same plane as ventrites 1–2. 9. Tylodinus zilchi (schematic). 10. Tylodinus sepulturaensis (schematic) 11. Tylodinus rugosus (schematic).

FIGURES 12–19. 12. Tylodinus pusillus head a) male, b) female. 13–14. Dorsal habitus of pronotum showing the lateral side of pronotum 13. Tylodinus andersoni, 14. Tylodinus porvenirensis. 15–17. Dorsal habitus: 15. Tylodinus rugosus, 16. Tylodinus exiguus, 17. Tylodinus jonesi. 18. Tylodinus coapillensis note tubercle on elytra declivity base, 19. Tylodinus elongatus showing metasternal tooth.

FIGURES 100–109. Ventral and lateral habitus of median lobe: 100. Tylodinus andersoni, 101. Tylodinus cavicrus, 102. Tylodinus pseudocavicrus, 103. Tylodinus rugosus, 104. Tylodinus exiguus, 105. Tylodinus ixchel, 106. Tylodinus jonesi, 107. Tylodinus variabilis, 108). Tylodinus leoncortesi, 109. Tylodinus triumforium.

FIGURES 92–99. 92–99. Dorsal and lateral habitus: 92–93. Tylodinus gibbosus, 94–95. Tylodinus kissingeri, 96–97. Tylodinus pinguis. 98. Median lobe apex of: a) Tylodinus elongatus, b) Tylodinus exiguus, c) Tylodinus pseudocavicrus, d) Tylodinus rufus, e) Tylodinus rufus (squashed), 99. Tylodinus zilchi, ventral and lateral habitus of median lobe.

FIGURES 36–43. Dorsal and lateral habitus: 36–37. Tylodinus pseudocavicrus, 38–39. Tylodinus rugosus. 40–41. Tylodinus buchanani. 42–43. Tylodinus exiguus.

FIGURES 28–35. Dorsal and lateral habitus: 28–29. Tylodinus nodulosus, 30–31. Tylodinus zilchi, 32–33. Tylodinus andersoni, 34–35. Tylodinus cavicrus.