Abstract
The larvae of three Neotropical species of the diving beetle genus Laccophilus Leach (Laccophilus obliquatus Régimbart, L. paraguensis Régimbart and L. testudo Régimbart) are described and illustrated for the first time, with an emphasis on morphometry and chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of these species lack the primary setae LA10 and LA12, and have the primary seta CO7 articulated proximally on all coxae, two apomorphies that define the subfamily Laccophilinae. They are also characterized by a frontoclypeus truncate proximally in the first instar, the presence of pectens on legs, and the presence of secondary setae on first urogomphomere. These character states are apomorphies that define the genus Laccophilus Leach. The absence of pore PAc and the presence of a dense group of secondary spiniform setae dorsally at the base of the siphon in instar III may also characterize this genus, as similar states are not found in other dytiscids. On the other hand, L. obliquatus, L. paraguensis and L. testudo differ from the other species of Laccophilus known in detail in the presence of an additional seta on the stipes and in the absence of pore ABc. Brief comments on the putative phylogenetic relationships of Laccophilinae and Laccophilus inferred from larval morphology, as well as on the characters potentially useful in studying relationships within the group are presented.References
Alarie, Y. (1995) Primary setae and pores on the legs, the last abdominal segment, and the urogomphi of larvae of Nearctic Colymbetinae (Coleoptera: Adephaga: Dytiscidae) with an analysis of their phylogenetic relationships. The Canadian Entomologist, 127, 913–943.
Alarie, Y. (1998) Phylogenetic relationships of Nearctic Colymbetinae (Coleoptera: Adephaga: Dytiscidae) based on chaetotaxic and porotaxic analysis of head capsule and appendages of larvae. The Canadian Entomologist, 130, 803–824.
Alarie, Y., Archangelsky, M., Nilsson, A.N. & Watts, C.H.S. (2002a) Larval morphology of the genus Lancetes (Coleoptera: Adephaga: Dytiscidae): the hypothesis of sister-group relationship with the subfamily Dytiscinae revisited. The Canadian Entomologist, 134, 467–501.
Alarie, Y. & Larson, D.J. (1998) Larvae of Agabinus Crotch: generic characteristics, description of A. glabrellus (Motschulsky), and comparisons with other genera of the subfamily Colymbetinae (Coleoptera: Adephaga: Dytiscidae). The Coleopterists Bulletin, 52, 339–350.
Alarie, Y. & Michat, M.C. (2007) Phylogenetic analysis of Hydroporinae (Coleoptera: Dytiscidae) based on larval morphology, with description of first instar of Laccornellus lugubris. Annals of the Entomological Society of America, 100, 655–665.
Alarie, Y., Nilsson, A.N., Hendrich, L., Watts, C.H.S. & Balke, M. (2000) Larval morphology of four genera of Laccophilinae (Coleoptera: Adephaga: Dytiscidae) with an analysis of their phylogenetic relationships. Insect Systematics & Evolution, 31, 121–164.
Alarie, Y., Spangler, P.J. & Perkins, P.D. (1998) Study of the larvae of Hydrotrupes palpalis Sharp (Coleoptera: Adephaga, Dytiscidae) with implications for the phylogeny of the Colymbetinae. The Coleopterists Bulletin, 52, 313–332.
Alarie, Y., Spangler, P.J. & Steiner W.E. Jr. (2002b) Larval morphology of Agabetes Crotch (Coleoptera: Adephaga: Dytiscidae): the hypothesis of sister-group relationship with the subfamily Laccophilinae revisited. The Coleopterists Bulletin, 56, 547–567.
Alarie, Y. & Watts, C.H.S. (2004) Larvae of the genus Antiporus (Coleoptera: Dytiscidae) and phylogenetic implications. Invertebrate Systematics, 18, 523–546.
Barman, E.H. (2004) A description of the first instar larva of Coptotomus interrogatus (Fabricius) (Coleoptera: Dytiscidae: Coptotominae) with an emphasis on cranial morphology and comments on the phylogeny of basal lineages of Dytiscidae. The Coleopterists Bulletin, 58, 661–671.
Benetti, C.J., Régil Cueto, J.A. & Garrido González, J. (2003) Estudio faunístico de Hydradephaga (Coleoptera: Dytiscidae, Gyrinidae, Haliplidae, Noteridae) en el municipio de Gramado, sur de Brasil. Boletín de la Sociedad Entomológica Aragonesa, 32, 37–44.
Bertrand, H. (1972) Larves et nymphes des coléoptères aquatiques du globe. F. Paillart, France, 804 pp.
Biesiadka, E. & Kazmierska, I. (2004) Contribution to the morphology of the third-instar larvae of Laccophilus poecilus Klug (Coleoptera: Dytiscidae). Genus, 15, 31–36.
Burmeister, E.-G. (1976) Der ovipositor der Hydradephaga (Coleoptera) und seine phylogenetische Bedeutung unter besonderer Berucksichtigung der Dytiscidae. Zoomorphologie, 85, 165–257.
De Marzo, L. (1976) Studi sulle larve dei coleotteri ditiscidi. V. Note morfologiche sulle larve di tre specie del genere Laccophilus Leach. Entomologica, Bari, 12, 107–129.
De Marzo, L. (1978) Studi sulle larve dei coleotteri ditiscidi. IX. Morfologia delle mandibole delle larve in alcune specie delle subff. Laccophilinae e Hydroporinae. Ipotesi sulla derivazione morfogenetica dei relativi modelli di mandibola. Entomologica, Bari, 14, 137–157.
De Marzo, L. (1979) Studi sulle larve dei coleotteri ditiscidi. X. Anatomia e funzionamento dell'aparato succhinate cibario-faringeo in alcune forme larvali delle subff. Dytiscinae, Colymbetinae, Laccophilinae e Hydroporinae. Entomologica, Bari, 15, 5–72.
De Marzo, L. & Nilsson, A.N. (1986) Morphological variation and fine structure of some head structures in larvae of Dytiscidae (Coleoptera). Entomologica Basiliensia, 11, 29–42.
Fukuda, A., Kurosa, K. & Hayashi, N. (1959) Coleoptera. In: Kawada, A. et al. (Eds.), Illustrated Insect larvae of Japan. Hokuryukan, Tokyo, pp. 391–546.
Galewski, K. (1978) Diagnostic characters of the larvae of the European species of Laccophilus Leach (Coleoptera, Dytiscidae). Bulletin de L'académie Polonaise des Sciences, 26, 263–268.
Hagenlund, G. & Nilsson, A.N. (1985) Larval morphology, habitat, and life cycle of the predaceous diving beetle Laccophilus stroehmi (Col., Dytiscidae). Fauna Norvegica, Ser. B, 32, 37–39.
Hilsenhoff, W.L. (1992) Dytiscidae and Noteridae of Wisconsin (Coleoptera). I. Introduction, key to genera of adults, and distribution, habitat, life cicle, and identification of species of Agabetinae, Laccophilinae and Noteridae. The Great Lakes Entomologist, 25, 57–69.
Larson, D.J., Alarie, Y. & Roughley, R.E. (2000) Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic region, with emphasis on the fauna of Canada and Alaska. NRC Research Press, Ottawa, Ontario, Canada, 982 pp.
Lawrence, J.F. (1991) Order Coleoptera. In: Stehr, F.W. (Ed.), Immature Insects, vol. 2. Kendall/Hunt Publishing Company, Iowa, pp. 144–658.
Michat, M.C. (2006) The phylogenetic position of Hydrovatus Motschulsky: evidence from larval morphology of H. caraibus Sharp (Coleoptera: Dytiscidae: Hydroporinae). Insect Systematics & Evolution, 37, 419–432.
Michat, M.C., Alarie, Y., Torres, P.L.M. & Megna, Y.S. (2007) Larval morphology of the diving beetle Celina and the phylogeny of ancestral hydroporines (Coleoptera: Dytiscidae: Hydroporinae). Invertebrate Systematics, 21, 239–254.
Michat, M.C., Archangelsky, M. & Torres, P.L.M. (2005) Descriptions of the preimaginal stages of Lancetes marginatus (Steinheil) and L. biremis Ríha (Coleoptera: Dytiscidae), and comparative notes with other Lancetes larvae. Studies on Neotropical Fauna and Environment, 40, 129–142.
Michat, M.C. & Torres, P.L.M. (2005) Larval morphology of Macrovatellus haagi (Wehncke) and phylogeny of Hydroporinae (Coleoptera: Dytiscidae). Insect Systematics & Evolution, 36, 199–217.
Michat, M.C. & Torres, P.L.M. (2008) On the systematic position of the diving-beetle genus Pachydrus (Coleoptera: Dytiscidae: Hydroporinae): Evidence from larval chaetotaxy and morphology. European Journal of Entomology, 105, 737–750.
Miller, K.B. (2001) On the phylogeny of the Dytiscidae (Insecta: Coleoptera) with emphasis on the morphology of the female reproductive system. Insect Systematics & Evolution, 32, 45–92.
Nilsson, A.N. (1988) A review of primary setae and pores on legs of larval Dytiscidae (Coleoptera). Canadian Journal of Zoology, 66, 2283–2294.
Nilsson, A.N. (1989) On the genus Agabetes Crotch (Coleoptera: Dytiscidae), with a new species from Iran. Annales Entomologici Fennici, 55, 35–40.
Nilsson, A.N. (2001) World Catalogue of Insects, vol. 3: Dytiscidae (Coleoptera). Apollo Books, Stenstrup, Denmark, 395 pp.
Ribera, I., Hogan, J.E. & Vogler, A.P. (2002) Phylogeny of Hydradephagan water beetles inferred from 18S rRNA sequences. Molecular Phylogenetics & Evolution, 23, 43–62.
Ribera, I., Vogler, A.P. & Balke, M. (2008) Phylogeny and diversification of diving beetles (Coleoptera: Dytiscidae). Cladistics, 24, 563–590.
Ruhnau, S. & Brancucci, M. (1984) Studies on the genus Lancetes. 2. Analysis of its phylogenetic position using preimaginal characters (Coleoptera, Dytiscidae). Entomologica Basiliensia, 9, 80–107.
Shaverdo, H.V. (1999) Contribution to the larval morphology of the third-instar larvae of Laccophilus hyalinus (Deg.) and L. minutus (L.) (Coleoptera: Dytiscidae). Genus, 10, 37–46.
Sizer, R.L., Barman, E.H. & Nichols, G. (1998) Biology of Laccophilus fasciatus rufus Melsheimer (Coleoptera: Dytiscidae) in Central Georgia with descriptions of its mature larva and pupa . Georgia Journal of Science, 56, 106–120.
Trémouilles, E.R. (1998) Dytiscidae. In: Morrone, J.J. & Coscarón, S. (Dirs.), Biodiversidad de artrópodos argentinos. Una perspectiva biotaxonómica. Ediciones Sur, La Plata, pp. 210–217.
Watts, C.H.S. (1970) The larvae of some Dytiscidae (Coleoptera) from Delta, Manitoba. The Canadian Entomologist, 102, 716–728.
Wiley, E.O. (1981) Phylogenetics. The theory and practice of phylogenetic systematics. John Wiley & Sons, New York, 439 pp.
Wilson, C.B. (1923) Water beetles in relation to pondfish culture, with life histories of those found in fishponds at Fairport, Iowa. Bulletin of the Bureau of Fisheries, 39, 232–345.
Wolfe, G.W. (1985) A phylogenetic analysis of plesiotypic Hydroporinae lineages with an emphasis on Laccornis Des Gozis (Coleoptera: Dytiscidae). Proceedings of the Academy of Natural Sciences of Philadelphia, 137, 132–155.
Zimmerman, J.R. (1970) A taxonomic revision of the aquatic beetle genus Laccophilus (Dytiscidae) of North America. Memoirs of the American Entomological Society, 26, 1–275.