Cylindridia, Casey

Prena, Jens, 2006, A preliminary study Cylindridia with descriptions of new species from Middle America (Coleóptera: Baridinae), Beiträge Zur Entomologie = Contributions to Entomology 56 (1), pp. 189-198 : 190-192

C y lin d rid ia C a s e y

Limnobaris auct., not B e d e l 1885-183. C a s e y 1892.

Cylindridia C a se y 1920-493. Type species Centrinusprolixus L e C o n t e (by original designation).

Recognition: Species of Cylindridia can be recognized by the following character states and biological data: (1) body shape elongate, slender and parallel-sided, Fig. 1-3 ; (2) pygidium covered by elytral apices; (3) rostrum sexually dimorphic in terms of length and width, Fig. 21-28 ; (4) male with deep pectoral cavity and pair of slender, anteriorly projecting prosternal spines usually visible from above, both structures reduced or entirely absent in depauperate specimens; (5) fore tibia in both sexes with ventrodistal spur not larger than tarsal claw; (6) claws curved and separate at base; (7) larval development in pith of flowering culms of Cyperaceae.

Discussion: C ylindridia is a genus with peculiar, anteriorly projecting prosternal spines that seemed to be restricted to the Nearctic region, whereas this character state occurs rather frequently in Neotropical genera. The southward extension of the range now adds to a geographically more consistent distribution of these weevils.

Species of Cyperaceae are the host of Cylindridia and numerous other genera in temperate (B o v in g 1924, Sa t t e r t h w a it 1942, P a l m 1957, D ie c k m a n n 1991, Y o s h ih a r a & M o r im o t o 1994) and tropical regions (P a r n e l l 1970, A n d e r s o n & P e c k 1994, Yo s h ih a r a & M o r im o t o 1997). Relatively few of them have the above mentioned spines. The most likely candidate to be confused with Cylindridia is Sibariops C a sey, species of which are less elongate and almost always (indistinct in a Costa Rican population of the S. confusus complex) possess a greatly enlarged, anteriorly directed spur at the apex of the fore tibia of the male. A future taxonomic revision of this genus shall explore its distinctiveness to Cylindridia based on representative material of the diverse South American fauna. The separation of the various genera becomes less clear, when the prosternal spines are disregarded in their classification. As this character state is extremely variable and its phylogenetic value remains unexplored, a concise diagnosis of Cylindridia is not possible at this stage and should be targeted in a comprehensive study of all relevant taxa, which are assigned to no less than three tribes at present.

Distribution: Neotropical (Mexico, Costa Rica, Brazil; new records) and Nearctic regions (U.S.A. and southern Canada, east of Rocky Mountains)

Life H istory [based on C. rubripes and C.Juscipes]: The female visits newly emerged culms of large-sized species of Carex, Rhynchospora and possibly other Cyperaceae, where it deposits single eggs in the lowest accessible, unsheathed portion of the apical internode. One to several males may congregate nearby, often in the inner angle of the adjacent leaf or in the developing inflorescence. Any usage of their prosternal spines, such as for ritual fighting over females as reported for Parisoschoenus expositus by E b e r h a r d & G a r c ia -C. (2000), has not been observed. The next oviposition on the same culm occurs, when new non-infested substrate of the old internode or a new unsheathed internode has grown basally. It appears, that the female probes whether or not sufficient non-infested tissue is available. Large culms may contain up to five specimens of different developmental stages, with the oldest specimen found in the apical section, the next-younger specimen boring in the basally adjacent 10-15 cm long section, and so on. The larva tunnels down part of the pithy interior of the culm, where it pupates among yellowish frass without preparing a cocoon. The host plant shows no evidence of physical damage or grossly impaired production of seeds, probably because the vascular system remains largely unaffected. The adult exits the now desiccated culm through a self-made spherical hole. Parasitic wasps were not encountered while rearing immatures from approximately 25 culms of Carex donnell-smithii and Rhynchospora ruiziana collected at two locations. Other weevils observed on the same hosts were Cholusfoveolatus C h a m p io n, Molytini (up to three larvae in the short, succulent stem from where basal leaves and culm emerge; INBC) and an unidentified species of Macroscytalus B r o u n, Cossonini (larvae possibly in the seeds as suggested by exit-holes; JPPC).

Key to the species of C ylindridia occurring in North and Middle America

1 Derm aeneous, rarely with slight bluish or greenish metallic luster, flanks ofpronotum and abdomen with white hairs; low and mid-elevations in United States and southern Canada (Nova Scotia, Québec, Ontario, Manitoba) east of Rocky Mountains.................................. .................................................................................................................... C. prolixa (L e C o n t e)

Derm dark green to cupreous, with strong metallic luster, body glabrous, without discernable hairs; Middle America, high elevations between 2000-3100 m.............................................2

2 Antennal club compact, approximately as long as distal four funicular segments combined ( Fig. 21 ); femora dark metallic, tibiae and tarsi red; southern Mexico................................... ......................................................................................................................... C. propinqua sp. n.

Antennal club more elongate, at least as long as distal five funicular segments combined ( Fig. 23 ); legs of uniform color, either dark metallic or reddish; Costa Rica (and probably western Panama)............................................................................................................................. 3

3 Legs red; elytral stria 10 not impressed subdistally; rostrum as long as or longer than pronotum; male without angularly projecting lamellar process ventrad of antennal insertion; female with rostrum weakly curved throughout ( Fig. 23 )........................ C. rubripes sp. n.

Legs dark metallic; elytral stria 10 impressed subdistally; rostrum shorter than pronotum; male with angularly projecting lamellar process ventrad of antennal insertion; female with rostrum notably curved in distal one-third ( Fig. 25 )................................. C. fuscipes sp. n.

Figures

Fig: 1-3: Dorsal habitus of 1, C. rubripes, male; 2, C.fuscipes, female; 3, Cylindridia sp. A, male.

Fig: 21-28: Head and prothorax, lateral. C.propinqua-. 21, female; 22, male. C. rubripes-. 23, female; 24, male. C.fuscipes-. 25, female; 26, male. Cylindridia sp. A: 27, female; 28, male.