Illustrated key to the genera of ground and tiger beetles of Galapagos (Coleoptera, Carabidae)

Transcription

1 BU LL ETIN DE L'!NSTITUT ROYAL DES SCIENCES NATURE LLES DE BELGIQUE ENTOMOLOG IE, 71: , 2001 BULL ETIN VAN HET KON INKL IJK BELGISCH!NSTITUUT VOOR NATUURWETENSCHAPPEN ENTOiytPLOGIE, 71: , 200 I Illustrated key to the genera of ground and tiger beetles of Galapagos (Coleoptera, Carabidae) by Konjev DESENDER Abstract An illustrated key is given to the genera of Carabidae (incl. Cici ndelinae) of the Galapagos Archipelago (Ecuador). Original habitus figures are added fo r Galapagos species of each of the 15 genera actu all y known to th e Archipelago. Four genera are mentioned for th e first time in Galapagos. Key words: Galapagos, Carabidae, genera identificati on key Resume Une clef d ' identificat ion illustn!e est presentee sur les genres de Carabidae (incl. Cicindelinae) des lies Galapagos (Ecuador). Des figures ori ginales d' habitus (especes de Gahipagos) sont ajoutees pour chacun des. 15 genres actuellement connus des lies. Quatre genres sont mentionnes pour Ia premiere fois aux lies Galapagos. Mots-clefs: Galapagos, Carabidae, clef d'identifi cation des genres Introduction Studies on the beetles and spiders of Galapagos were started in the eighti es at the Royal Belgian Insti tute for Natural Sciences and have been continued since (reviewed by BAERT et al., 1994; BAERT, 2000). During the last decade, other research groups joined these eff011s on the study of the terrestrial invertebrates of the archipelago (Schatz & Schatz, Peck & co-workers; cf. PECK, 1996). As a result, several taxa, including the ground and tiger beetles (DESENDER el al., 1992a) are fairly well-known today. Galapagos invertebrates are much more spec ies-rich than vertebrates, in many taxa demonstrate high levels of endemism, show a large variati on of life cycles, distribution and geographical range sizes and suggest a variety of speciation scenari os (DESENDER el a!., 1992a; PECK, 1996). The fi rst detailed account on Galapagos ground and ti ger beetl es (Carabidae, including Cicindelinae) was given by VAN DYKE ( 1953), who treated some 25 species. Some 15 years later, BASILEWSKY ( 1968) revised the Galapagos Calosomini. PECK & PUKALOVA-PECK (1 990) mentioned 35 ground and tiger beetles for the Galapagos. DESENDER et al. (1 992a) treated some 40 species belongmg to II genera, whil e mentioning uncertainties fo r the exact number of species belongmg to the genera Agoman, Bradyce!lus, Pterostichus, Selenophorus and Tachys. More recentl y collected material (Desender & co-workers unpublished data) yielded members from 4 addi tional gene; a to thi s ground beetl e li st: these most probably incl ude several spec ies recentl y introduced to the Archipelago (see also DESEN DER eta/, 1992b; DESEN DER eta/, in press). In summary, ground and ti ger beetles belong to one of the largest beetle families in the Galapagos, with some species. Patterns of di stribution and speciati on of several Galapagos ground beetles were already discussed in an earli er paper (DESENDER el a/., 1992a). Today, many taxonomic/systematic problems remain unresolved in Galapagos ground beetl es, partly as a result of unreliable or incompl ete descriptions by others in the past. We recently also started studying these by means of molecul ar techniques (e.g. DESENDER & VERDYCK, 2000). In most of the Galapagos ground beetle genera, systematic, ecological and molecul ar studies are therefore still in progress (Desender & co-workers). Also because of the increased introducti on of allien spec ies during recent decades in Galapagos, there is a growing need for an identification key and an updated recent checklist of the Galapagos spec ies in thi s beetle fa mily. As, at this moment, a reliable and complete checklist cannot yet be given with much confidence, we have started, as a first step, to prepare an illustrated key to all genera of ground and tiger beetles, CLUTently known to us from Galapagos. This is the obj ecti ve of this short paper. The main purpose is to stimulate and make easier future monitoring studies in Ga lapagos. The key should enable entomology students or scientists, unfa miliar with Carabid systematics, to identify, at least wi th certainty to genus level, any of the ground and tiger beetles, currently known to us from Galapagos. Deta iled keys to species level are in preparation (DE SENDER & PECK, in prep.) and will be included in the planned comprehensive treatment of all Galapagos beetles (P ECK, in prep. ). An updated checklist is also plaru1ed for the near future (DESENDER, in prep.). In the foll owing key to the Galapagos carabid genera, all 15 genera are illusttated by a Galapagos species (ori ginal fi gures). Nomenclature primarily fo llows REICHARDT ( 1977). Names between brackets refer to genus or subgenus names used by other authors, but also mentioned in REICHARDT ( 1977). Four of these 15 genera have never been menti oned before for Ga lapagos: Acupalpus, Calleida, Hal/oc01yza and Thalpius.

2 258 Konjev DESENDER: Key to genera of Galapagos Carabidae 3 4 Figs Habitus of Galapagos species belonging to the genus (I) Cicindela (TL [total length] = 8,5-1 4,5 mm), (2) Calosoma (TL = mm), (3) Tachys (TL = I,5-3,5 mm) and ( 4) Bembidion (TL = 2,5-3,5 mm) Figs Habitus of Galapagos species belonging to the genus (5) HalocOi yza (total length "' 2-2,5 mm), (6) Scm ires (TL = mm), (7) Se/enophorus (TL = 7-11 mm) and (8) Bradycel/us (TL "' 2,5-4 nu11).

3 Short Notes 259 Illustrated identification key to the genera of ground and tiger beetles of Galapagos Ia. lb. 2a. 2b. 3a. 3b. 4a. 4b. Sa. Sb. 6a. 6b. 7a. 7b. 8a. 8b. 9a. 9b. Clypeus broader than distance between antenna! insertions (ti ger beetles); elytra without striae and glabrous (Fig. I) Cicinde/a LII\'NAEUS, (Cicinde/idia RI VA LI ER, 1954) Clypeus narrower than distance between antenna) insertions; elytra mostly with stri ae (sometimes diffuse) or pubescent Elytron with more than 12 striae and 3 tuberculate interva ls (Fig. 2); fore coxal cavities open behind Calosoma WEBER, 180 I (Castrida MOTSCHULSKY, 1865) Elytron with less than II stri ae (abbreviated scutellar stria not counted) or without stri ae; fore coxal cavities closed behind Pronotum and elytral intervals pubescent, each at least with one row of seti ferous punctures Pronotum and elytra glabrous (except for apical or lateral setae and dorsal punctures in at most three intervals). 4 Last segment of max ill ary palp at most about a third as long as preceding one; total length not exceeding 4 mms Last segment of maxill ary pal pi about as long or longer than preceding one Elytra without scutellar stria; sutural stria extended and hooked (recurrent) along apex (use light source from behind) (F ig. 3) Tachys STEPHENS, 1828 Elytra with scutellar stria and more strongly punctuated striae; sutura l stria not recwtent (F ig. 4) Bembidion (sensu /ato) LATREILLE, 1802 Forebody pedunculate (scutellum situated entirely in front of elytra); fossorial carabids with enl arged protibia.. 7 Scutellum at least partly situated between elytra; normal protibia and body Frons with two supra-orbital punctures (with setae); head capsule with 8 distinct longitudinal ridges; mandibles simple, small er than 3 mm (Fig. 5) HalocotJ'Za ALLUAUD, 1919 Frons without supra-orbital punctures; enl arged mandibl es with extra teeth; stout beetl es, larger than 15 mm (Fig. 6) Sc(// i/es FABRJCIUS, 1775 Frons with one supra-orbital punct11re (and accompagnying large seta) near eye Frons with two supraorbital punctures near eye (punctures all ways visible even if setae are broken) II Elytral striae 2, 5 and 7 mostly with setigerous punctures; mentum without tooth; body larger (mostly over 7 mm) (Ftg. 7) Selenophorus DEJEAN, 1829 Elytral with striae 2, 5 and 7 impunctate; body smaller loa. lob. II a. II b. 12a. l2b. l3a. 13b. 14a. 14b. 15a. 15b. (less than 5 mm) I 0 Ment11m without tooth; 2 to 4 mm (Fig. 14) Acupa/pus LATREILLE, 1829 Mentum with tooth; 2,5 to 4 mm (Fig. 8) Bradyce//us ERICHSON, 1837 Pronotum pentagonal wi th lateral sides protruding at middle; head markedly constricted at neck, eyes very much protruding (Fig. 9). Pentagonica SCHM IDT-GOEBEL, 1846 Pronotum with lateral sides not protruding at middle; eyes norma I Apex of elytra transversely truncate; tarsal claws pectinate; consp iciously bicoloured beetles with dark head, orange pronotum and metallic green-blue elytra (F ig. l 0) Ca //eida DEJ EAN, 1825 Apex of elytra rounded; tarsal claws simple Elytra with epipleura crossed near apex (Fig. 1 1) Pterostichus (sensu /ato) BONELLI, (8/ennidus MOTSCHULSKY, 1865) Elytra with epipleura not crossed near apex (Fig. 12) Platynus (sensu lato) BONELLI, (Dysco/us DEJEAN, 183 1) Eyes absent; last segment of max ill ary palp much shorter than preceding one; very small, not over I,5 mm (F ig. 13) Mystroceridius REICHARDT, 1970 Eyes present; small to medium-sized beetles Frons with a single seta-bearing supra-orbital puncture inside eye; elytra rounded at apex; very small (2 mm), pale beetles with enti re ly pubescent antenna (Fig. 14) Acupa/pus LATREILL E, 1829 Frons with two supra-orbital punctures inside eye; antenna pubescent fro m second segment onwards; elytra truncate at apex, about 4,5-6 mm (Fig. 15) Tha/pius LE CONTE, 1851 Acknowledgements We acknowledge the Belgian DWTC (former Ministry of Education), the Leopold Ill foundation and the Fund for Scientific Research - Flanders for financial support. Exce llent cooperat ion and fi eld logistic support was pro~id e d by the Charles Darwin Research Station (CDRS, Santa Cruz, Galapagos), G. Reck, C. Blanton and R. Bensted-Smith, Directors and their staff, and the Ga lapagos National Park Service, F. C~peda, A. lzuri eta and E. Cruz, Superintendents (Dept. of Forestry, Mmistry of Agnculture, Ecuador). TAME airline kindly issued reduced travel tickets. Smcere thanks to my co lleagues Dr. L. Baert, Dr. J.P. Maelfatt and Dr. P. Verdyck for their continued help in these studies and to S. Sandoval, Dr. S. Abedrabbo, Dr. H. & I. Schatz, Prof. Dr. S. Peck, Dr. L. Roque, Dr. Ch. Causton and Mrs. G. Estevez for loan of additional Galapagos beetles or assistance in our field work. Eliane De Bock is acknowledged for making most of the beetle drawings. Dr. P. Verdyck kindly vol untered to test the key.

4 260 Konjev DESENDER: Key to genera of Galapagos Carabidae Figs Habitus of Galapagos species belonging to the genus (9) Pentagonica (total length = 4-5 mm), ( I 0) Calleida (TL = 6,5-7 mm), (II) Pterostichus (TL = mm) and ( 12) Agonum (Dyscolus) (TL = 7,5-13 nu11). 13 Figs Habitus of Galapagos species belonging to the genus ( 13) Mystroceridius (total length = 1-1,3 mm), ( 14) Acupa/pus (TL = 2-4 mm) and ( 15) Thai pius (TL = 4,5-6 mm).

5 Short Notes 261 I I References BAERT, L. MAELFAIT, J.-P., DESENDER, K Evolutionary ecology, systematics and population geneti cs of terrestrial arthropods in the Galapagos Archipelago (Ecuador). Univ. Gent: Biodiversity: study, exploration, conservati on. Proceedings of a Symposium organized by the Royal Society of Natural Sciences Dodonaea BAERT, L Invertebrate research overview: I. Terrestrial arthropods. Proceedings of the Symposium 'Science for conservation in Galapagos'. Bulleti n de I ' lnstitut Royale des Sciences naturelles de Belgique, Entomologie, Supplement, 70: BAS IL EWSKY, P., Ill. Les Calosomes des li es Galapagos (Coleoptera Carabidae). In : Leleup, N. & J. (ed.) Mission zoologique beige aux iles Galapagos et en Ecuador, I, Bruxelles: DESENDER, K., BAERT, L., MAE LFAIT, J.-P., 1992a. Distribution and speciation of carabid beetles in the Galapagos Archipelago (Ecuador). Bulletin de l 'lnstitut Royal des Sciences Na ture/les de Belgique (En tomologie), 62: DESENDER, K., BAERT, L., MAELFAIT, J.-P., 1992 b. El Ninoevents and the establishment of ground beetles in the Galapagos Archipelago. Bulletin de I 'fnstitut Royal des Sciences Naturelles de Belgique (Entomologie), 62: DESENDER, K., CASALE, A., BAERT, L., MAE LFAIT, J.-P. & VERDYCK, P. (in press). Ca/leida migratoria Casale, n. sp. (Coleoptera: Carabidae), a newly introduced grou nd beetle in the Galapagos islands, Ecuador. Coleopterists Bulletin. DESENDER, K., VERDYCK, P., Genetic differentiation in the Galapagos caterpillar hunter Calosoma granatense (Coleoptera, Carabidae). In: BRANDMAY R, P et al. (ed.). Natural History and Applied Ecology of Carabid Beetles. Pensoft Publishers, Sofi a, Moscow: LINSLEY, E.G Insects of the Galapagos (Supplement). Occasional Papers of the California Academy of Sciences, San Francisco, 125 : PECK, S.B Origin and development of an insect fauna on a remote archipelago: The Galapagos Islands, Ecuador. [pp ]. In : The ori gin and evolution of Pacific Island biotas, New Guinea to Eastem Polynes ia: pattems and processes (Keast, A. and Miller, S. E., editors). Amsterdam, The Netherlands: Academic Publishing. PECK, S. B., KUKALOYA-P ECK, J., Origin and biogeog~ a phy of the beetles (Coleoptera) of the Galapagos Archipelago, Ecuador. Canadian Journal of Zoology, 68: REI CHARDT, H., A contribution to the knowledge of the Carabidae of the Galapagos Islands (Coleoptera). pp , in: Mission zoologique beige aux lies Galapagos et en Ecuador (N. et J. Leleup, ). Resultats scientifiques. Troisieme partie. Koninklijk Museum voor Midden-Afrika, Tervuren, pp REI CHARDT, H., A synopsis of the genera of Neotropical Carabidae (Insecta: Coleoptera). Quaestiones Entomologicae 1977; 13: VAN DYKE, E. C., The Coleoptera of the Galapagos Islands. Occasional Papers of the California Academy of Sciences, San Francisco, No. 22, 181 pp. Konjev DESENDER Department Entomology Roya l Belgian Institute of Natural Sciences Vautierstraat 29 B Brussel ( e-mai I: Ko nj ev.desender@naturalsciences.be)