Key to the South America genera of Elmidae (Insecta: Coleoptera) with distributional data

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1 Studies on Neotropical Fauna and Environment, December 2005; 40(3): ORIGINAL ARTICLE Key to the South America genera of Elmidae (Insecta: Coleoptera) with distributional data VERÓNICA MANZO Faculty of Natural Sciencies, National University of Tucumán, Tucumán, Argentina (Received 5 July 2004; accepted 7 April 2005) Abstract A key for the adults of all South American genera of the family Elmidae is provided. The key includes nine genera presently assigned to the subfamily Larainae and 29 genera assigned to the subfamily Elminae. Distributional data for all genera are also included. Keywords: Elmide, riffle beetle, Elminae, Larainae, South America Introduction Elmidae is a common and widespread family of beetles, which includes two subfamilies: Larainae and Elminae, both present in South America. With 38 genera and more than 250 species described in this region, riffle beetles are very common in lotic habitats. The genera Phanoceroides, Pagelmis, Stenhelmoides, Stegoelmis, Jolyelmis, Gyrelmis, Onychelmis, Pilielmis, Stethelmis, Hintonelmis, Neolimnius, Oolimnius, Portelmis, Austrelmis, Tyletelmis, Epodelmis, Holcelmis, Tolmerelmis, Luchoelmis and Notelmis are endemic from the Neotropical region. The genus Austrolimnius is shared with the Australian region and the genera Macrelmis, Xenelmis, Neoelmis, Heterelmis, Hexacylloepus, Microcylloepus and Cylloepus are Neotropical although some species inhabit the Nearctic region. The genus Huleechius was described by Brown (1981a) from Mexico and California (USA); however he mentioned records of larvae from Ecuador and Bolivia suggesting that the distribution of this genus is more extended. In the subfamily Larainae the genera Roraima, Pharceonus, Hexanchorus, Disersus, Potamophilops, Pseudodisersus and Neblinagena are Neotropical while the genus Phanocerus is shared with the Nearctic region and the genus Hydora with the Australian region. Despite being so widely distributed in South America, no comprehensive key to the South American genera of riffle beetles has ever been published. Contributions usually include only the genera of a specific region. Hinton, whose contributions are very important for our knowledge of the elmid Neotropical fauna, provided in 1940(a) a monographic revision of the Mexican Elmidae, including a key for all the genera of this country. He also published in 1940(b) a key for all the genera of Elmidae from Peru and Bolivia. More recently, Brown (1981b) provided a key for the world genera of Larainae; Spangler and Santiago- Fragoso (1987, 1992) published revisions of the genera of Larainae from Mexico and Central America and Trémouilles et al. (1995) published a key for the riffle beetles of Argentina that also included some genera of neighboring countries as Bolivia and Brazil. The catalogue of Blackwelder (1944, 1957) and Brown s paper (1981c) on the world genera of riffle beetles are very helpful to know the South American fauna. Although these keys and checklists can be useful for other countries, many new taxa at both generic and specific levels have been added recently, extending the distribution of a large number of genera. Preimaginal stages of Elmidae are poorly known from the Neotropical region. Of the 38 described genera from South America in 19 the larvae have not been described: 17 of the subfamily Elminae (Phanoceroides, Pagelmis, Stenhelmoides, Jolyelmis, Correspondence: Verónica Manzo, Faculty of Natural Sciences, National University of Tucumán, Miguel Lillo 205 (4000) Tucumán, Argentina. vmanzo@csnat.unt.edu.ar ISSN print/issn online ª 2005 Taylor & Francis DOI: /

2 202 V. Manzo Gyrelmis, Onychelmis, Sthethelmis, Hintonelmis, Neolimnius, Oolimnius, Portelmis, Tyletelmis, Tolmerelmis, Epodelmis, Holcelmis and Notelmis), Luchoelmis and two of the subfamily Larainae (Potamophilops and Neblinagena). Bertrand (1956, 1965, 1972) summarized all that is known on larval stages of the family Elmidae and these papers are useful but outdated. There are some papers with keys for the larvae of some genera such as Hinton (1940a) or Spangler and Santiago-Fragoso (1987, 1992). Nevertheless the majority of the contributions are only descriptions of larvae, as in Brown (1971) or more recently Springer and Rivas (2003). Since larvae are known for no more than half of the genera, no comprehensive key is yet possible for preimaginal stages. Finally, it is possible to use the White and Brigham (1996) keys for larvae and adults from North America and also for those genera shared with South America. Methods The key is based on specimens from the collections of: Instituto Fundación Miguel Lillo, Tucumán, Argentina from Brazil, Peru, Paraguay, Bolivia and Argentina; Institut royal des sciences naturelles de Belgique, Bruxelles, Belgique from Peru and National Museum of Natural History, Smithsonian Institution (USNM), Washington, USA from Peru. Additional material was supplied by Dr H. Brown (University of Oklahoma, Oklahoma, USA) from USA and Mexico and by Dr. W. Shepard (University of California, Berkeley, California, USA) from Costa Rica and Belize. Information of some genera not available was obtained from the bibliography. The morphological nomenclature follows Brown (1976) and Spangler and Santiago-Fragoso (1987, 1992). Results Key to the subfamilies of Elmidae (Insecta: Coleoptera) of South America adults 1. Adults only occasionally aquatic, generally fly. Body densely pubescent, without plastron. Procoxae transverse and trochantin exposed Larainae (A) Adults aquatic. Body not or scarcely pubescent, with plastron. Procoxae globose and trochantin not exposed... Elminae (B) (A) Key to the genera of the subfamily Larainae 1. Pronotum very distinctive, with two short prescutellar carinae on posterior margin and lateral margins with sinuate carina on each postero-lateral half. Pronotal disc with U-shaped convexity on anterior 3/5 and short, prebasal, transverse carina on each side of midline. Venezuela...Roraima Pronotum with depression and/or groove. Pronotal disc without convexity or carinae Length less than 5 mm...3 Length more than 5 mm Elytra with accessory basal stria. Chile and Argentina... Hydora Elytra without accessory basal stria Pronotum without distinct transverse depression on apical 1/3, with arcuate sublateral depressions (Figure 1). USA (Texas), Central America, Caribbean, Peru and Argentina... Phanocerus Pronotum with distinct transverse depression on anterior 1/3 (Figure 3), with or without arcuate sublateral depression Pronotum with arcuate, sublateral, sub-basal, medial and transverse depressions (Figure 2). Costa Rica, Panama and Peru... Pharceonus Pronotum without arcuate sublateral depressions; with deep transverse depression on apical 1/3 (Figure 3). Central America, Caribbean, Ecuador, Bolivia and Argentina...Hexanchorus 6. Pronotum without transverse groove across apical 1/3. Costa Rica, Panama, Ecuador, Colombia and Perú...Disersus Pronotum with distinct transverse groove across apical 1/ Pronotum without lateral longitudinal carinae or arcuate-sinuate groove (Figure 4). Brazil and Argentina... Potamophilops Pronotum with lateral longitudinal carinae or arcuate-sinuate groove Pronotum with two prescutellar tubercles at base and one near each posterolateral angle, thus appearing bidentate (Figure 5). Costa Rica, Panama, Colombia and Ecuador...Pseudodisersus Pronotum without prescutellar tubercles at base or posterolateral angles, with two short, converging, prescutelar carinae, each with a deep lateral pit. Venezuela...Neblinagena (B) Key to the genera subfamily Elminae 1. Antennae with five apical segments forming a club (Figure 6)...Phanoceroides Antennae filiform Head opisthognathus. Pronotum with strong anterior and posterior depression adjacent to lateral margin; with transverse groove at apical 1/3 and strong oblique groove al basal 1/3; without sublateral carinae. Chile and Argentina Luchoelmis

3 Elmids 203 Figures Phanocerus sp. (1): pronotum. Pharceonus sp. (2): pronotum (modified from Spangler & Santiago-Fragoso 1992). Hexanchorus sp. (3): pronotum. Potamophilops cinereus (4): pronotum (modified from Spangler & Santiago 1987). Pseudodisersus sp. (5): pronotum (modified from Spangler & Santiago-Fragoso 1992). Phanoceroides acautica (6): antenna (modified from Hinton 1939b). Pagelmis amazonica (modified from Spangler 1981) (7a): prosternal process; (7b): male hind leg. Stenhelmoides sp. (8): dorsal view. Austrolimnius sp (9a): epipleuron, (9b): dorsal view. Macrelmis sp. (10): dorsal view. Stegoelmis sp. (modified from Spangler 1990) (11a): pronotum; (11b): elytral apex.

4 204 V. Manzo Figures Gyrelmis sp. (modified from Hinton 1940c) (12): dorsal view. Onychelmis sp. (modified from Hinton 1941) (13a): dorsal view; (13b): tarsal claws. Stethelmis chilensis (modified from Hinton 1945) (14a): tarsal claws; (14b): prosternal process; Hintonelmis sp. (15) dorsal view. Neolimnius palpalis (modified from Hinton 1939a) (16a): labium; (16b): pronotum. Xenelmis sp. (17) dorsal view. Oolimnius sp (modified from Hinton 1939a) (18): pronotum. Portelmis sp. (modified from Spangler 1980) (19): dorsal view. Neoelmis sp. (20): dorsal view. Austrelmis sp. (21): dorsal view.

5 Elmids 205 Figures Heterelmis sp. (22): dorsal view. Tolmerelmis pubipes (modified from Hinton 1936) (23): middle tibia of male. Hexacylloepus sp. (24): dorsal view. Microcylloepus sp. (25): dorsal view. Notelmis nodipes (26): dorsal view. Huleechius marroni (modified from Brown 1981a) (27a) labium and gula; (27b) hind wing. Cylloepus sp. (28a): dorsal view; (28b) hind wing.

6 206 V. Manzo Head prognathous. Pronotum variable, but not as above Head, pronotum and elytra with large dorsal areas with plastron (Figure 8b), ventral areas of body with plastron. Pronotum without carinae and depressions. Elytra without carinae, may have rows of granules from base to apex...4 Plastron mainly on ventral surface of body, if present on dorsal surface only as small areas. Pronotum usually with carinae and depression, seldom absent. Elytra with or without longitudinal carinae Tibiae without cleaning fringes. Sides of prosternal process parallel and narrow, around 1/3 as wide as long (Figure 7a). Trochanters of male hind legs with apicoventral tubercle (Figure 7b). Ecuador... Pagelmis Tibiae with apical cleaning fringes, prosternal process large and wide (Figure 8a). Trochanters of male hind legs without apicoventral tubercle (Figure 8b). Central America, French Guiana, Venezuela, Colombia, Ecuador, Peru and Brazil...Stenhelmoides 5. Epipleura with one or two longitudinal lines of granules (Figure 9a), elytra with prominent sublateral carinae on 5th and 7th intervals (Figure 9b). Mexico, French Guiana, Ecuador, Bolivia, Brazil, Argentina and Chile... Austrolimnius Epipleura without longitudinal line of granules Elytra with short accessory stria between striae and (Figure 10). USA, Central America and South America...Macrelmis Elytra without accessory striae Basal 1/3 of pronotum with gibbosities or protuberances (Figure 11a, b), usually four transversally, sometimes sublateral gibbosities absent but inner ones always present. Pronotum with or without longitudinal depression and sublateral carinae. Elytra with coarse punctate striae, humeral and subapical areas usually with gibbosities or protuberances. French Guiana, Venezuela, Colombia, Brazil, Ecuador, Peru, and Paraguay... Stegoelmis Pronotum and elytra without gibbosites or protuberances. Pronotum and elytra generally with sublateral carinae Pronotum and each elytron with three high, longitudinal carinae, metasternum with an arcuate, lateral carina on each side of disc. Arcuate carina extending from medial margin of each metacoxal cavity to posterior margin of first abdominal sternum. Venezuela... Jolyelmis Protonotum and each elytron with one or two longitudinal carinae, sometimes absent, metasternum variable, but not as above Elytra with sublateral carinae on 5th and 7th intervals (Figure 12). French Guiana and Brazil... Gyrelmis Elytra without sublateral carinae on intervals 5th and 7th Tarsal claws with one or two teeth (basal and sub-basal) (Figures 13b and 14)...11 Tarsal claws without teeth Tarsal claws with basal and sub-basal teeth (Figure 13a, b). Costa Rica, Panama, Colombia, Ecuador and Peru...Onychelmis Tarsal claws with only basal tooth (Figure 14) Elytra with short row of granules on basal part of 4th interval, being this part of the interval subcarinate; sublateral carina on 6th interval. Pronotum with sublateral carinae, center of disc with a distinct oval depression, and each side of disc with another distinct oval depression on basal 1/5 against sublateral carina. French Guiana and Brazil......Pilielmis Elytra usually without carina, but if present not on 4th interval. Pronotum not as above Tomentum on all hypomera and sides of mesosternum. Prosternum short, prosternal process long, moderately narrow with apex rounded (Figure 14b). Protibiae without cleaning fringes. Elytra without carina. Chile and Argentina... Stethelmis Tomentum only on anterior area of hypomera, mesosternum without tomentum. Prosternum long, prosternal process subquadrate and as broad between coxae as length of coxae, apex bisinuate. Protibiae with cleaning fringes. Elytra usually with carinae on 6th and 8th intervals, seldom absent (Figure 15). French Guiana, Brazil, Peru, and Paraguay... Hintonelmis 14. Lacinia and galea very long, narrow and nearly parallel-sided (Figure 16a). Pronotum with deep and complete transverse depression on apical 2/5, with a nearly complete sublateral longitudinal carina and sublateral carina on each side of basal 1/4 of sublateral carinae. Basal margin of pronotum not emarginate in front of scutellum (Figure 16b). Brazil... Neolimnius Lacinia and galea short and broad. Pronotum variable Disc of pronotum without longitudinal depression...16 Disc of pronotum with medial longitudinal depression Body broad, oval, usually small (2.2 mm). Pronotum without depressions, subtriangular (Figure 17)...17 Body side s subparallel. Pronotum subrectangular, sublateral carinae and depressions present or absent Body length less than 2 mm. Pronotum tomentose. Pronotum without sublateral carinae (only X. granata presents a sublateral carina extending from base to about apical 1/4) or depressions. Elytra with

7 Elmids 207 two sublateral carinae (Figure 17). USA, Central America, Brazil, Peru, Ecuador, and Argentina...Xenelmis Body length more than 2 mm. Pronotum not tomentose and nearly complete sublateral carinae present (Figure 18). Elytra with sublateral carinae composed of low rows of granules. Brazil......Oolimnius 18. Elytra with deep, lateral, marginal excavation near elytral apex, accompanied by prolonged lateral margins of the 5th sternite, which fits into this cavity. Pronotum usually without carinae; if present each carina is short and basal. Elytra without carinae (Figure 19) Costa Rica and Ecuador Portelmis Elytra without marginal excavation near elytral apex. Pronotum and elytra generally carinate Pronotum with deep and complete transverse depression on anterior 2/5 and with sublateral carinae (Figure 20). Elytra with sublateral carina on 6th interval. Body sometimes very small. USA, Central America, Caribbean, Ecuador, Colombia, Bolivia, Brazil and Argentina... Neoelmis Pronotum without transverse depression, if present never complete. Elytra with one or two sublateral carinae Pronotum with or without sublateral carinae. If present, carinae much higher and more prominent on apical half, if carinae extend to the base they are completely divided at basal 2/5 by an oblique depression; transverse depression absent or very shallow. Elytra with two, one or no sublateral carinae (if present, carinae are on intervals 6 and 8) (Figure 21). Ecuador, Peru, Bolivia, Chile and Argentina...Austrelmis Pronotum with carinae well-developed, transverse depression generally present, carinae never divided at base. Elytra with one or two carinae Body sides subparallel. Pronotum with welldeveloped carinae extending from base to about apical 1/6. Elytra with one carina. Brazil Tyletelmis Body subovate (Figure 22). Pronotum with sublateral carinae, wich extend from base to anterior margin. Pronotal disc generally with or rarely without a transverse depression at middle. Elytra with carinae on 6th and 8th intervals. USA, Central America, Caribbean, Brazil, Ecuador, Peru, Bolivia and Argentina... Heterelmis 22. Pronotum with shallow transverse depression on basal 2/5 and sublateral carina well-developed; disc of pronotum with a broad, deep, median longitudinal depression. Posterior cleaning fringe of middle tibia, in male, exceptionally long (Figure 23). Brazil and Argentina... Tolmerelmis Pronotum without transverse depression. Posterior cleaning fringe of middle tibia in males short Hypomera completely tomentose or with complete transverse belt of tomentum...24 Hypomera without tomentum, shining. Occasionally a very narrow belt of tomentum adjacent to sterno-notal suture or near procoxae present Hypomera completely tomentose. Bolivia......Epodelmis Hypomera with a belt of tomentum on anterior part Sides of pronotum strongly dilated. Prosternum and disc of first abdominal sternite without sublateral carinae. Cuticule without hard and rigid aspect. Bolivia... Holcelmis Sides of pronotum not dilated. Prosternum and disc of first abdominal sternite with sublateral carinae. Cuticle hard and rigid (Figure 24). USA, Central America, Caribbean, French Guiana, Venezuela, Peru, Brazil and Argentina... Hexacylloepus 26. Pronotum with oblique and transverse depressions, longitudinal depressions sometimes present...27 Pronotum without oblique and transverse depressions. Longitudinal depressions present Pronotum with sublateral carina and with transverse depression, with a median longitudinal discal depression; basal half on each side with an oblique depression. Elytra with two sublateral carinae (sometimes with one or three) (Figure 25). Epipleura rarely tomentose. USA, Central America, Caribbean, French Guiana, Brazil, Peru, Chile and Argentina...Microcylloepus Pronotum without sublateral carina; with deep and complete transverse depression; with median longitudinal depression on middle of disc and from base on each side a shallow oblique depression. Elytra with two sublateral carinae (Figure 26); epipleura tomentose. Costa Rica, Panama and Ecuador......Notelmis 28. Labium with gula distinctly narrower than submentum and mentum (Figure 27a). Elytra with two sublateral carinae. Hind wing without 3A 2 (Figure 27b); tibiae of male with pronounced secondary sexual characters. USA, Mexico, Ecuador and Bolivia...Huleechius Labium with gula as wide as submentum and mentum. Elytra with two sublateral carinae (Figure 28a). Hind wing with 3A 2 (Figure 28b). Tibiae of male variable. USA, Central America, Caribbean, Brazil, Peru, Bolivia and Argentina...Cylloepus Acknowledgments I want to thank M. Archangelsky and W. Shepard for suggestions on an early version of the manuscript and the loan of material and E. Dominguez for useful

8 208 V. Manzo comments. The author is a doctoral fellow of CONICET, and this manuscript was supported by PIP no /2000 (CONICET) and PICT no (ANPCyT). References Bertrand HPI Notes sur les premiers états des Dryopides d Amérique. Ann Soc Entomolo France 124: Bertrand HPI Notes sur les premiers états des Dryopides d Amérique (Col) (Addendum). Bull Soc Entomolo France 70: Bertrand HPI Larves et Nymphes des Coléoptéres aquatiques du globe. Abbeville, France: F. Paillat, 804 p. Blackwelder RH Checklist of the coleopterous insects of Mexico, Central America, the West Indies, and South America. US National Mus Bull 185: Blackwelder RH Checklist of the coleopterous insects of Mexico, Central America, the West Indies, and South America. US National Mus Bull 18(6): Brown HP (1971): Neotropical Dryopoids III. New records of Xenelmis with description of the larva (Coleoptera: Elmidae). The Coleopterist Bulletin 2(3): Brown HP (1976): Aquatic Dryopoid beetles (Coleoptera) of the United States. Water Pollution Control Research Series 18050, 269 p. Brown HP. 1981a. Huleechius, a new genus of riffle beetles from Mexico and Arizona (Coleoptera, Dryopidae, Elmidae). Pan Pac Entomol 57: Brown HP. 1981b. Key to the world genera of Larinae (Coleoptera, Dryopidae, Elmidae) with descriptions of new genera from Hispaniola, Colombia, Australia and New Guinea. Pan Pac Entomol 57(1): Brown HP. 1981c. A distributional survey of the world genera of riffle beetles (Coleoptera: Dryopoidea: Dryopidae, Elmidae and Psephenidae). Pan Pac Entomolol 57(1): Hinton HE Descriptions and figures of new Brazilian Dryopidae (Coleoptera). Entomologist 69: Hinton HE. 1939a. On some new genera and species of Neotropical Dryopidae (Coleoptera). Trans Roy Entomolol Soc London 89(3): Hinton HE. 1939b. An inquiry into the natural classification of the Dryopoidea based partly on a study of their internal anatomy (Coleoptera). Trans Roy Entomol Soc London 89(7): Hinton HE. 1940a. A monographic revision of the Mexican water beetles of the family Elmidae. Novitates Zoologicae 42(2): Hinton HE. 1940b. The Percy Sladen Trust Expedition to Lake Titicaca in 1937 under the leadership of Mr. H. Gary Gilson VII. The Peruvian and Bolivian species of Macrelmis Mostch. (Coleoptera, Elmidae). Trans Linn Soc London ser 3(1): Hinton HE. 1940c. A monograph of Gyrelmis gen. n., with a study of the variation of the internal anatomy (Coleoptera: Elmidae). Trans Roy Entomol Soc London 90 (13): Hinton HE New genera and species of Elmidae (Coleoptera). Trans Roy Entomol Soc London 91(3): Hinton HE Stethelmis chilensis, new genera and species of Elmidae from Chile (Coleoptera). Entomol Soc London: Spangler PJ A new species of riffle beetle genus Portelmis from Ecuador (Coleoptera: Elmidae). Proc Entomol Soc Wash 82(1): Spangler PJ Pagelmis amazonica, a new genus and species of water beetle from Ecuador (Coleoptera: Elmidae). Pan-Pac Entomolo 57: Spangler PJ A revision of the Neotropical aquatic beetle genus Stegoelmis (Coleoptera: Elmidae). Smithsonian Contributions to Zoology 502, 52 p. Spangler PJ, Santiago S A revision of the Neotropical aquatic beetle genera Disersus, Pseudodisersus and Potamophilops (Coleoptera: Elmidae). Smithsonian Contributions to Zoology 446, 40 p. Spangler PJ, Santiago-Fragoso S The aquatic beetle subfamily Larainae (Coleoptera: Elmidae) in Mexico, Central America and the West Indies. Smithsonian Contributions to Zoology 528, 74 p. Springer M, Rivas RA First description of the larva of Pharceonus Spangler et Santiago-Fragoso, 1992 and new records for the genus (Coleoptera: Elmidae: Larainae). Aquat Insect 25(3): Trémouilles ER, Oliva A, Bachmann AO Insecta Coleoptera. In: Lopretto EC, Tell G, editors. Ecosistemas de Aguas Continentales, Vol. 3. La Plata: ediciones Sur, p White DS, Brigham WU Aquatic Coleoptera. In: Merritt RW, Cummins KW, editors. Aquatic insects of North America. 3rd ed. Kendall/Hunt Publishing Company, Dubuque, p