Tylodinus pusillus, Luna-Cozar & Anderson & Jones & León-Cortés, 2014

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 : 39

Tylodinus pusillus species group

Recognition. The species of this group are distinguished from other Tylodinus by having in combination the body size 2.3 mm or less; pronotum with punctures dense to contiguous at the base and progressively more widely spaced, smaller and shallower to the apex ( Figures 14, 16–17 ); female with the median section of ventrite 2 with a transverse line of scales along midline ( Figure 24 ).

Diagnosis. Body 1.9–2.1x longer than wide. Head clothed with yellow scales, punctures similar to punctures on rostrum; vertex with dense to contiguous scales, similar in coloration and tonality to scales on head, uniformly distributed along vertex; rostrum moderately robust, moderately carinate, apical area puncticulate; eyes moderately convex. Pronotum in dorsal view moderately convex, outline with anterior constriction and without posterior constriction ( Figure 10 ); in dorsal view with sides slightly divergent from base to midlength, then convergent to apex, constricted beyond middle ( Figure 14 ); disc hollowed or somewhat hollowed, punctures dense to contiguous at base and progressively more widely spaced, smaller and shallower to apex ( Figures 14, 16–17 ), clothed with yellow scales, very dense on lateral sides and flanks, anterior area and forming thick longitudinal fringe along the middle and narrow strip that diverges from middle base to flanks, and with dark brown scales on middle and posterior areas of disc ( Figure 14 ). Elytra black, basal margin slightly sinuate; tubercle distribution as follows: I2 with a tubercle on the base of declivity, I3 with two tubercles: first tubercle subbasal, second tubercle on middle of elytra, I4 with two tubercles: first tubercle small, positioned between tubercles on I3, second tubercle on base of elytral declivity, similar in size or longer than tubercle on I2, I5 with two tubercles in same position as tubercles on I3. Metasternum moderately concave, glabrous in median section; metasternal tooth absent. Male abdomen with ventrite 1 concave, median section glabrous; ventrite 2 feebly concave, male with median section glabrous, female with transverse line of scales along middle line ( Figures 24–25 ), as long as or longer than ventrites 3–4 combined; ventrite 5 convex along median line, as long as ventrite 1, with an anterior-median impression. Femora armed or unarmed, hind femora length not reaching elytra apex, tibiae subparallel, premucro absent. Male genitalia ( Figures 115–116 ) with the median lobe in lateral view weakly curved, stout or moderately stout; in ventral view as long as or ½ length that of apodeme, lateral sides straight, subparallel or convergent, apex acute; apical process large (0.35–0.42 as long as median lobe), slightly curved; in ventral view not constricted beyond the median orifice, convergent.

Key to species of Tylodinus pusillus species group

1 Legs black; femora unarmed ( Figures 68–69 ).............................................. T. pusillus Luna-Cozar

- Legs reddish; femora armed ( Figures 70–71 ).......................................... T. porvenirensis Luna-Cozar

Figures

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 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 110–119. Ventral and lateral habitus of median lobe: 110. Tylodinus sepulturaensis, 111. Tylodinus lum, 112. Tylodinus spiniventris, 113. Tylodinus mutabilis, 114. Tylodinus parvus, 115. Tylodinus pusillus, 116. Tylodinus porvenirensis, 117. Tylodinus elongatus, 118. Tylodinus complicatus, 119. Tylodinus rufus.

FIGURES 68–75. Dorsal and lateral habitus: 68–69. Tylodinus pusillus, 70–71. Tylodinus porvenirensis, 72–73. Tylodinus elongatus, 74–75. Tylodinus complicatus.