Tylodinus nodulosus (Boheman, 1837)

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 : 14-15

Tylodinus nodulosus species group

Recognition. The species of this group are distinguished from other Tylodinus by having the pronotum in lateral view strongly convex, in outline slanting downward from the highest point to the apex ( Figure 9), anterior constriction absent; in dorsal habitus, sides slightly divergent from base to midlength, then convergent to apex ( Figure 13); disc deeply medially excavate ( Figures 28, 30 and 32). Rostrum slender. Elytra with tubercles laminate or elongate ( Figures 29, 31, 33).

Diagnosis. Body 1.8–2.1x longer than wide, black, clothed with obovate, short scales, light brown to ferruginous. Head with dense contiguous scales; vertex with a patch of overlapping scales, yellow or same color as scales of head; rostrum slightly convex, slender, not carinate, surface with fine, shallow punctures, scattered, similar to punctures on head, apical area puncticulate; frons moderately concave, eyes flush with outline of head. Pronotum in lateral view strongly convex, outline slanting downward from highest point to apex and base, anterior constriction absent ( Figure 9); in dorsal view with sides slightly divergent from base to midlength, then convergent to apex; disc deeply excavate, with protuberance on median section of disc (two species) or not (one species); surface with punctures more or less uniformly distributed, granulate and rugose; scales dense on edge of pronotal excavation, more widely separated towards lateral and median areas of disc ( Figure 13). Elytra black, basal margin strongly sinuate (two species) to slightly sinuate (one species); scales denser on higher tubercles, along sutural interval and interval 2 on declivity, becoming more separated toward the flanks; surface granulate, tubercles laminate ( Figures 29, 31, 33). Metasternum moderately concave, with the median section glabrous and smooth (one species) or with scales (two species), metasternal tooth absent. Abdomen with ventrites 3–5 not in same plane as ventrites 1–2, ventrite 1 moderately concave, squamous, ventrite 2 concave (one species) or weakly concave (two species), as long as ventrites 3–4 combined (one species) or longer (two species), squamous (one species) or with transverse line of scales (two species), ventrite 5 as long as ventrite 1, without impressions (two species) or with anterior impression (one species). Femora armed, with fine granules between punctures, punctures feeble on hind femur; hind femora length extending beyond elytral apex; tibiae elongate and narrow, subparallel, slightly curved at apical one-quarter, with large punctures, deep and dense; premucro present or only visible on front tibiae (one species). Male genitalia ( Figures 99–100) with median lobe (not examined for T. nodulosus ) in lateral view stout, weakly curved; in ventral view as long as apodemes, sides straight, convergent or subparallel, apex blunt; apical process in lateral view weakly curved, abruptly curved downward, moderate in width, in ventral view small or moderately large, constricted beyond the median orifice, lateral sides subparallel.

Key to species of Tylodinus nodulosus species group

1 Pronotum with a protuberance on excavated median section of disc ( Figure 32).................................... 2

- Pronotum without protuberance on excavated median section disc ( Figures 30–31)..................... T. zilchi Kuschel

2(1) Elytral declivity with tubercle on interval 3 elongate and merged with tubercle on interval 2; protuberance on median section of disc divided by a longitudinal carina ( Figures 28–29).................................... T. nodulosus (Boheman)

- Elytral declivity with tubercle on interval 3 laminate, large, tubercle on interval 2 absent; protuberance on median section of disc not divided ( Figures 32–33)....................................................... T. andersoni Luna-Cozar