New information on the feeding habits of the percomorph Rhenanoperca minuta, together with a short look at other fish species from the Eocene Messel Formation of Germany


Authors: Micklich N, Baranov V, Wappler T

Published in: Bulletin of Geosciences, volume 94, issue 3; pages: 315 - 336; Received 21 August 2018; Accepted in revised form 7 May 2019; Online 1 July 2019

Keywords: Messel Pit, actinopterygian fishes, nutrition, pharyngeal dentition, cannibalism, speciation,

full text (PDF, 14.8 MB)

Export to RIS



Forage remains were studied in the digestive tracts of four Messel fish species (Rhenanoperca minuta, Thaumaturus intermedius, Cyclurus kehreri, Atractosteus messelensis). They were found in only 4% of all samples. Particular attention was paid to R. minuta. Herein, depending on the investigation method, between 0.7% and 13% of the samples contained conspecific prey fish and/or prey fish remains. In total 1.6% contained remains of amphipod shrimps. Concerning T. intermedius, prey (arthropod) remains could be found only in one sample (3.4%). Similarly, only one (6.6%) of the bowfins (C. kehreri) and none of the gars (A. messelensis) contained such remains. The pharyngeal jaws of R. minuta exhibit two basic types of dentition. One is characterized by strong, flattened (“molariform”) pharyngeal teeth, and the other by more delicate and slender (“papilliform”) ones. This polymorphism may be indicative of a beginning or advancing speciation. The different morphotypes probably originated in adjacent water bodies (allopatric) rather than in Lake Messel itself (sympatric). The results were discussed with particular attention to extant comparable species. The high rate of evacuated digestive tracts in R. minuta very probably results from a shortage of suitable prey, and possibly also from environmental restrictions. For the other species, different factors, like diurnal or seasonal fluctuations may have played a more important role. For R. minuta, a diet switch from predominantly arthropods to fish, especially a switch to T. intermedius as a main prey, can be discarded. Rather there appears to have been a gradual transition from soft-bodied arthropods to gastropods, as known from comparable recent species, even actual though direct evidence (gastric or intestinal contents, or even co-occurrence with abundant gastropods) could not observed among the investigated fossils.


Andreae, A. 1893. Vorläufige Mitteilung über die Ganoiden (Lepisosteus und Amia) des Mainzer Beckens. Verhandlungen des naturhistorisch-medizinischen Vereins, Neue Folge 5, 7-15.

Barel, C.D.N., van Oijen, M.J.P., Witte, F. & Witte-Maas, E.L.M. 1977. An introduction to the taxonomy and morphology of the haplochromine Cichlidae from Lake Victoria. Part A + B. Netherlands Journal of Zoology 27(4), 333-389. View article

Berry, F.H. 1955. Food of the mudfish (Amia calva) in Lake Newnan, Florida, in relation to its management. Quarterly Journal of the Florida Academy of Sciences 18(1), 69-75.

Binning, S.A. & Chapman, L.J. 2008. Feeding ecology and diet overlap in riverine chichlids from western Uganda. Verhandlungen der Internationalen Vereinigung für Limnologie 30(2), 283-286. View article

Boy, J.A. 2003. Paläoökologische Rekonstruktion von Wirbeltieren: Möglichkeiten und Grenzen. Paläontologische Zeitschrift 77(1), 123-152. View article

Carlander, K.D. 1977. Handbook of freshwater fishery biology, Vol. II. 431 pp. Iowa State University Press, Ames.

Carlander, K.D. 1997. Handbook of freshwater fishery biology, Vol. III. 418 pp. Iowa State University Press, Ames.

Craig, J.F. 2000. Percid fishes. Systematics, ecology and exploitation. 370 pp. Blackwell Sciences Ltd., Malden. View article

Cuvier, G. & Valenciennes, A. 1829. Histoire naturelle des poissons, Vol. 3. Des percoides a dorsale unique a sept rayons branchiaux et a dents en velours ou en cardes. 500 pp. Levrault, Paris.

DeKay, J.E. 1842. Zoology of New-York, or the New-York fauna; comprising detailed descriptions of all the animals hitherto observed within the state of New-York, with brief notices of those occasionally found near its borders, and accompanied by appropriate illustrations. Part IV. 415 pp. White & Visscher, Albany. View article

Diana, M.C. 1966. Diet of the bowfin in Central Florida. Quarterly Journal of the Florida Academy of Sciences 29(4), 276-284.

Donald, D.B. & Kooyman, A.H. 1977. Food, feeding habits, and growth of goldeye, Hiodon alosoides (Rafinesque), in waters of the Peace-Athabasca Delta. Canadian Journal of Zoology 55, 1038-1047. View article

Dugas, C.N., Konikoff, M. & Trahan, M.F. 1976. Stomach contents of bowfin (Amia calva) and spotted gar (Lepisosteus oculatus) taken in Henderson Lake, Louisiana. Proceedings of the Louisiana Academy of Sciences 39, 28-34.

Eikamp, H. 1982. Allzuviel ist ungesund. Beutefisch in der Bauchhöhle eines Schlammfisches. Mineralien-Magazin 3, 112-113.

Gaudant, J. & Micklich, N. 1990. Rhenanoperca minuta nov. gen., nov. sp., ein neuer Percoide (Pisces, Perciformes) aus der Messel-Formation (Mittel-Eozän, Unteres Geiseltalium). Paläontologische Zeitschrift 64, 269-286. View article

George, E.L. & Hadley, W.F. 1979. Food and habitat partitioning between rock bass (Ambloplites rupestris) and smallmouth bass (Micropterus dolomieui) young of the year. Transactions of the American Fisheries Society 108, 253-261. View article

Gerkin, S.D. 1994. Feeding ecology of fish. 418 pp. Academic Press, San Diego.

Goldspink, C.R. & Goodwin, D. 1979. A note on the age composition, growth rate and food of perch Perca fluviatilis (L.) in four eutrophic lakes, England. Journal of Fish Biology 14, 489-505. View article

Gottfried, M.D. 1986 Developmental transition in feeding morphology of the Midas Cichlid. Copeia 1986(4), 1028-1030. View article

Grande, L. 2010. An empirical synthetic pattern study of Gars (Lepisosteiformes) and closely related species, based mostly on skeletal anatomy. American Society of Ichthyologists and Herpetologists Special Publication 6, 1-871.

Grande, L. 2013. The lost world of Fossil Lake: Snapshots from Deep Time. 432 pp. University of Chicago Press, Chicago. View article

Grande, L. & Bemis, W.E. 1998. A comprehensive phylogenetic study of amiid fishes (Amiidae) based on comparative skeletal anatomy. An empirical search for interconnected patterns of natural history. Society of Vertebrate Paleontology, Memoir 4, Journal of Vertebrate Paleontology 18(1), 1-690. View article

Greenwood, P.G. 1972. Morphology, endemism and speciation in African cichlid fishes. Verhandlungen der Deutschen Zoologischen Gesellschaft 1972, 115-124.

Grein, M., Utescher, T., Wilde, V. & Roth-Nebelsick, A. 2011. Reconstruction of the middle Eocene climate of Messel using palaeobotanical data. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 260(3), 305-318. View article

Günther, A. 1859. Catalogue of the acanthopterygian fishes in the collection of the British Museum. Gasterosteidae, Berycidae, Percidae, Aphredoderidae, Pristipomatidae, Mullidae, Sparidae. 524 pp. British Museum (Natural History), London.

Günther, A. 1864. Report of a collection of fishes made by Messrs, Dow, Godman, and Salvin in Guatemala. Proceedings of the Zoological Society of London 1864, 144-154.

Herting, G.E. & Witt, A. 1968. Rate of digestion in the Bowfin. Progressive Fish-Culturist 30(1), 26-28. View article

Huish, M.T. 1957. Food habits of three Centrarchidae in Lake George, Florida. Proceedings of the Southeastern Association of Game and Fish Commissioners 11, 293-303.

Hulsley, C.D., Marks, J., Hendrickson, D.A., Williamson, C.A., Cohen, A.E. & Tephens, M.J. 2006. Feeding specialisation in Herichthys minckleyi, a trophically polymorphic fish. Journal of Fish Biology 68, 1399-1410. View article

Hunt, B.P. 1960. Digestion rate and food consumption of Florida Gar, Warmouth, and Largemouth Bass. Transactions of the American Fisheries Society 89(2), 206-211. View article

Huysseune, A. 1995. Phenotypic plasticity in the lower pharyngeal jaw dentition of Astatoreochromis alluaudi (Teleostei: Cichlidae). Archives of Oral Biology 40(11), 1005-1014. View article

Huysseune, H., Sire, J.Y. & Meunier, F.P. 1994. Comparative study of the lower pharyngeal jaw structure in two phenotypes of Astatoreochromis alluaudi (Teleostei: Cichlidae). Journal of Morphology 221, 25-43. View article

Juanes, F. 2003. The allometry of cannibalism in piscivorous fish. Canadian Journal of Fisheries and Aquatic Sciences 60, 594-602. View article

Juanes, F., Buckel, J.A. & Scharf, F.S. 2002. Feeding ecology of piscivorous fishes, 267-283. In Hart, P.J.B. & Reynolds, J.D. (eds) Handbook of Fish Biology and Fisheries, Vol 1. Wiley-Blackwell, Malden. View article

Kaiser, T. & Micklich, N. 1995. Schnellpräparation von Messel-Fossilien zum Erstellen einer osteologischen Referenzsammlung. Präparator 41(2), 69-72.

Keast, A. 1968. Feeding biology of the Black crappie, Pomoxis nigromaculatus. Journal of the Fisheries Research Board of Canada 25(2), 285-297. View article

Keast, A. 1978. Feeding interrelations between age groups of Pumpkinseed (Lepomis gibbosus) and comparisons with Bluegill (Lepomis macrochirus). Journal of the Fisheries Research Board of Canada 35, 12-27. View article

Keast, A. & Welsh, L. 1968. Daily feeding periodicities, food uptake rates, and dietary changes with the hour of day in some lake fishes. Journal of the Fisheries Research Board of Canada 25(6), 1133-1144. View article

Kirtland, J.P. 1840. Descriptions of four new species of fishes. Boston Journal of Natural History 3(1-2), 273-277.

Kofron, C.P. & Schreiber, A.A. 1983. The central mudminnow (Umbra limi) in Missouri, with an analysis of summer foods. Southwestern Naturalist 28(3), 371-372. View article

Kornfield, I. & Taylor, J.N. 1983. A new species of polymorphic fish, Cichlasoma minckleyi, from Cuatro Ciénegas, Mexico (Teleostei: Cichlidae). Proceedings of the Biological Society of Washington 96(2), 253-269.

Lacépede, B.G.E. 1802. Histoire naturelle des poissons. Vol. 4. 728 pp. Plassan, Paris.

Lagler, K.F. & Applegate, V.C. 1942. Further studies of the food of the bowfin (Amia calva) in Southern Michigan, with notes on the inadvisability of using trapped fish in food analyses. Copeia 1942(3), 190-191. View article

Lagler, K.F. & Hubbs, F.V. 1940. Food of the Long-nosed Gar (Lepisosteus osseus oxyurus) and the Bowfin (Amia calva) in Southern Michigan. Copeia 1940(4), 239-241. View article

Lagler, K.F. & Watts, J. 2004. Food of bowfins (Amia calva) from the Muskegon River at Houghton Lake, Roscommon County, Michigan. Michigan University Fisheries Research Report 569, 2 pp.

Lambou, V.W. 1962. The alligator gar. Wildlife Education Bulletin 30, 2-8.

Langton, R.W. 1977. A review of methods used for estimating gut evacuation rates and calculating daily ration for fish. Woods Hole Laboratory Reference 77-07, 1-26.

Laskar, K.S. 1942. Wachstum und Ernährung des Barsches (Perca fluviatilis L.) in ostholsteinischen Seen. Archiv für Hydrobiologie 49, 1009-1026.

Lesueur, C.A. 1829. Cantharus nigromaculatus, 88. In Cuvier, G. & Valenciennes, A. (eds) Histoire naturelle des poissons, Vol. 3. Des percoides a dorsale unique a sept rayons branchiaux et a dents en velours ou en cardes. Levrault, Paris.

Liem, K.F. 1979. Evolutions-Schub in Ostafrika. Wie Buntbarsche zu Räubern wurden. Spektrum der Wissenschaft 1979(5), 90-102.

Linnaeus, C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. 10th ed., Vol. 1. 824 pp. Laurentii Salvii, Holmiae. View article

Linnaeus, C. 1766. Systema naturae sive regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. 12th ed., Vol. 1. 532 pp. Laurentii Salvii, Holmiae. View article

Lombardi, S.E. 2009. Predation by Eastern Mudminnows (Umbra pygmaea) on macroinvertebrates of temporary wetlands. 45 pp. Master thesis, Maryland University, Maryland, USA.

McGrath, E.P., Hilton, E.J. & Musick, J.A. 2013. Temporal and spatial effects on the diet of an estuarine piscivore, longnose gar (Lepisosteus osseus). Estuaries and Coasts 36(6), 1292-1303. View article

Meyer, A. 1990. Morphometrics and allometry in the trophically polymorphic cichlid fish, Cichlasoma citrinellum: Alternative adaptations and ontogenetic changes in shape. Journal of Zoology 221, 237-260. View article

Micklich, N. 1978. Palaeoperca proxima, ein neuer Knochenfisch aus dem Mittel-Eozän von Messel bei Darmstadt. Senckenbergiana lethaea 59(4/6), 483-501.

Micklich, N. 1985. Biologisch-paläontologische Untersuchungen zur Fischfauna der Messeler Ölschiefer (Mittel-Eozän, Lutetium). Andrias 4, 3-171.

Micklich, N. 1992. Ancient knights-in-armour and modern cannibals, 71-92. In Schaal, S. & Ziegler, W. (eds) Messel - An Insight into the History of Life and of the Earth. Clarendon Press, Oxford.

Micklich, N. 1996. Percoids (Pisces, Perciformes) from the oil shale of the Messel Formation (Middle Eocene, Lower Geiseltalian): An ancient diversification? 113-127. In Lobon-Cervia, J., Elvira, J.B. & Granado-Lorencio, C. (eds) Fishes and their Environment. Proceedings of the 8th Congress of the Societas Europaea Ichthyologorum (SEI). Instituto Espan~ol de Oceanografi´a, Madrid.

Micklich, N. 2002. The fish fauna of Messel Pit: A nursery school? Courier Forschungsinstitut Senckenberg 237, 97-127.

Micklich, N. 2007. Coincidences or necessities? 585-629. In Gruber, G. & Micklich, N. (eds) Messel - Treasures of the Eocene. Hessisches Landesmuseum, Darmstadt.

Micklich, N. 2012a. Peculiarities of the Messel fish fauna and their palaeoecological implications: a case study. Palaeobiodiversity and Palaeoenvironments 92(4), 585-629. View article

Micklich, N. 2012b. An exceptional record of Thaumaturus intermedius Weitzel, 1933 from Messel Pit. Kaupia 18, 11-17.

Micklich, N. & Drobek, M. 2007. 15-21. Mining, excavations, and preparation. In Gruber, G. & Micklich, N. (eds) Messel - Treasures of the Eocene. Hessisches Landesmuseum, Darmstadt.

Micklich, N. & Klappert, G. 2004. Character variation in some Messel fishes, 137-163. In Arratia, G. & Tintori, A. (eds) Mesozoic Fishes 3 - Systematics, Palaeoenvironment and Biodiversity. Friedrich Pfeil, Munich.

Micklich, N. & Mentges, S. 2012. Fin ray fractures in Messel fishes. Kaupia 18, 73-81.

Mittelbach, G.G., Osenberg, C.W. & Wainwright, P.C. 1999. Variation in feeding morphology between pumpkinseed populations: Phenotypic plasticity or evolution? Evolutionary Ecological Research 1, 111-128.

Mittelbach, G.G. & Persson, L. 1998. The ontogeny of piscivory and its ecological consequences. Canadian Journal of Fisheries and Aquatic Sciences 55, 1454-1465. View article

Molnár, G., Tamassy, E. & Tölg, I. 1967. The gastric digestion of living, predatory fish, 135-149. In Gerkin, S.D. (ed.) The biological basis of freshwater fish production. Blackwell, Oxford & Edinburgh.

Moon, D.N., Fisher, S.J. & Krentz, S.C. 1998. Assessment of larval fish consumption by Goldeye (Hiodon alosoides) in two Missouri river backwaters. Journal of Freshwater Ecology 13(3), 317-321. View article

Nawrocki, B., Colborne, S.F., Yurkowski, D.J. & Fisk, A.T. 2016. Foraging ecology of Bowfin (Amia calva), in the Lake Huron-Erie Corridor of the Laurentian Great Lakes: Individual specialists in generalist populations. Journal of Great Lakes Research 42, 1452-160. View article

Netsch, N.F. & Witt, A. Jr. 1962. Contributions to the life history of the Longnose gar, (Lepisosteus osseus) in Missouri. Transactions of the American Fisheries Society 91(3), 251-262. View article

Neubert, E. 1999. The mollusca of the Eocene lake of Messel. Courier Forschungsinstitut Senckenberg 216, 167-181.

Nikolova, M., Uzunova, E., Studenkov, S., Georgieva, M., Pehlinvanov, L. & Velkov, B. 2008. Feeding patterns and seasonal variation in the diet of nonindigenous fish species Lepomis gibbosus L. from shallow eutrophic lakes along River Vit, Bulgaria. Natura Montenegrina 7(3), 71-85.

North American Native Fish Association. 2015. Fish in focus: Bowfin young-of-the-year, Amia calva.

O’Goghain, A., Falcon-Lang, H.J., Carpenter, D., Miller, R.F., Benton, M.J., Davies, T., Pufahl, P.K., Ruta, M., Hinds, S. &c Stimson, M. 2016. Fish and tetrapod communities across a marine to brackish salinity gradient in the Pennsylvanian (early Moscovian) Minto Formation of New Brunswick, Canada, and their palaeoecological and palaeogeographic implications. Palaeontology 59, 689-724. View article

Osenberg, C.W., Olson, M.H. & Mittelbach, G.G. 1994. Stage structure in fishes: Resource productivity and competition gradients, 151-170. In Stouder, D.J., Fresh, K.L., Feller, R.J. & Baruch, B.W. (eds) Therory and Application in fish Feeding Ecology. University of South Carolina Press, Columbia.

Panek, F.M. & Weis, J.S. 2013. Diet of eastern mudminnow (Umbra pygmaea DeKay) from two geographically distinct populations within the North American native range. Northeastern Naturalist 20(1), 37-48. View article

Peckham, R.S. & Dineen, C.F. 1957. Ecology of the central mudminnow, Umbra limi (Kirtland). American Naturalist 58(1), 222-231. View article

Pellegrin, J. 1904. Contribution a l’étude anatomique, biologique et taxinomique des poissons de la famille des Cichlidés. Mémoires de la Société Zoologique de France 16, 41-400.

Rafinesque, C.S. 1819. Prodrome de 70 nouveaux genres d’animaux découverts dans l’intérieur des États-Unis d’Amérique, durant l’année 1818. Journal de Physique, de Chimie et d’Histoire Naturelle 88, 417-429.

Rafinesque, C.S. 1820. Fishes of the Ohio River. Western Revue and Miscellaneous Magazine 1(6), 361-377.

Richter, G. 1992. Fossilized gut contents: analysis and interpretation, 71-92. In Schaal, S. & Ziegler, W. (eds) Messel - An Insight into the History of Life and of the Earth. Clarendon Press, Oxford.

Richter, G. & Baszio, S. 2001a. Traces of a limnic food web in the Eocene Lake Messel - a preliminary report based on fish coprolite analyses. Palaeogeography, Palaeoclimatology, Palaeoecology 166, 345-368. View article

Richter, G. & Baszio, S. 2001b. First proof of planctivory/insectivory in a fossil fish: Thaumaturus intermedius from the Eocene Lake Messel (FRG). Palaeogeography, Palaeoclimatology , Palaeoecology 173, 75-85. View article

Richter, G. & Baszio, S. 2006. First evidence of size-related change of diet (“switching?) in a fossil fish. Palaeogeography, Palaeoclimatology, Palaeoecology 237, 270-279. View article

Richter, G. & Wedmann, S. 2005. Ecology of the Eocene Lake Messel revealed by analysis of small fish coprolites and sediments from a drilling core. Palaeogeography, Palaeoclimatology, Palaeoecology 223, 147-161. View article

Richter, G., Baszio, S. & Wuttke, M. 2017. Discontinuities in the microfossil record of middle Eocene Lake Messel: clues for ecological changes in lake’s history? Palaeobiodiversity and Palaeoenvironments 97(2), 295-314. View article

Roth, R. & Micklich, N. 2006. Eine neue Methode zur Präparation kleiner Messel-Fossilien. Präparator 52, 64-67.

Sadzikowski, M.R. & Wallace, D.C. 1976. A comparison of the food habits of size classes of three sunfishes (Lepomis macrochirus Rafinesque, L. gibbosus (Linnaeus) and L. cyanellus Rafinesque). American Midland Naturalist 95(1), 220-225. View article

Schaal, S. & Rabenstein, R. 2012. Fossilienfundstätte Grube Messel - Übersichtskarten zur Betriebs- und Grabungsplanung. Forschungsinstitut Senckenberg, Arbeitsbereich Messelforschung.

Schaal, S. & Ziegler, W. (eds) 1992. Messel - An insight into the history of life and of the earth. 322 pp. Clarendon Press, Oxford; Oxford University Press, New York.

Schliewen, U.K., Tautz, D. & Pääbo, S. 1994. Sympatric speciation suggested by monophyly of crater lake cichlids. Nature 368(6472), 629-632. View article

Schliewen, U.K., Rassmann, K., Markmann, M., Markert, J., Kocher, T. & Tautz, D. 2001. Genetic and ecological divergence of a monophyletic cichlid species pair under fully sympatric conditions in Lake Ejagham, Cameroon. Molecular Ecology 10(6), 1471-1488. View article

Smith, L.S. 1980. Digestion in teleost fishes. In FAO (ed.) Fish feed technology. Lectures presented at the FAO/UNDP Training Course in Fish Feed Technology, Seattle, Washington (USA), 9 October-15 December 1978. UNDP/FAO, ADCP/REP/80/11. Rome.

Smith, C. & Reay, P. 1991. Cannibalism in teleost fish. Reviews in Fish Biology and Fisheries 1, 41-64. View article

Smylie, M., Shervette, V. & McDonough, C. 2015. Prey composition and ontogenetic shift in coastal populations of longnose gar Lepisosteus osseus. Journal of Fish Biology 87(4), 815-1128. View article

Storch, G. 2001. Palaeobiological implications of the Messel mammalian assemblage, 215-235. In Gunnell, G.F. (ed.) Eocene biodiversity: Unusual occurrences and rarely sampled habitats. Springer, Boston.

Tseitlin, V.B. 1980. Duration of gastric digestion in fishes. Marine Ecology Progress Series 2, 277-280. View article

Tyler, J.D. & Granger, M.N. 1984. Notes on food habits, size, and spawning behaviour of Spotted gar in Lake Lawtonka, Oklahoma. Proceedings of the Oklahoma Academy of Sciences 64, 8-10.

Wainwright, P.C. & Lauder, G.V. 1992. The evolution of the feeding biology in sunfishes (Centrarchidae), 472-491. In Mayden, R.L. (ed.) Systematics, Historical Ecology & North American Freshwater Fishes. Stanford University Press, Stanford. View article

Wainwright, P.C., Osenberg, C.W. & Mittelbach, G.G. 1991. Trophic polymorphism in the Pumpkinseed Sunfish (Lepomis gibbosus Linnaeus): Effects of environment on ontogeny. Functional Ecology 5(1), 40-55. View article

Walbaum, J.J. 1792. Petri Artedi sueci genera piscium. In quibus systema totum ichthyologiae proponitur cum classibus, ordinibus, generum characteribus, specierum differentiis, observationibus plurimis. Redactis speciebus 242 ad genera 52. 723 pp. Rose, Greifswald.

Wedmann, S. & Richter, G. 2007. The ecological role of immature phantom midges (Diptera, Chaoboridae) in the Eocene Lake Messel, Germany. African Invertebrates 48(1), 59-70.

Weitzel, K. 1933. Amphiperca multiformis n.g. n.sp. und Thaumaturus intermedius n.sp., Knochenfische aus dem Mitteleozän von Messel. Notizblatt des Vereins für Erdkunde und der Hessischen Geologischen Landesanstalt V(14), 89-97.

Werner, E.E. 1974. The fish size, prey size, handling time relation in several sunfishes and some implications. Journal of the Fisheries Research Board of Canada 31(9), 1531-1536. View article

Wichard, W., Gröhn, C. & Seredszus, F. 2009. Aquatic insects in Baltic amber. 335 pp. Kessel Publishers, Remagen.

Wilson, A.K., Noack-Kunnemann, K. & Meyer, A. 2000. Incipient speciation in sympatric Nicaraguan crater lake cichlid fishes: sexual selection, versus ecological diversification. Proceedings of the Royal Society of London, B 267, 2133-2141. View article

Zapata, S.C. & Granado-Lorencino, C. 1993. Age, growth and feeding of the exotic species Lepomis gibbosus in a Spanish cooling reservoir. Archiv für Hydrobiologie, Supplement 90, 561-573.