Extraordinary morphological changes in valve morphology during the ontogeny of several species of the Australian ostracod genus Bennelongia (Crustacea, Ostracoda)

  • Patrick De Deckker
  • Koen Martens Royal Belgian Institute of Natural Sciences
Keywords: Moulting, instar, nodes, pore morphology, setae


Ostracods belonging to the genus Bennelongia differ much in valve morphology between adults and juveniles. Adult valves are asymmetrical, characterised by a beak-like feature in the antero-ventral region of the left valve, and, with some notable exceptions, mostly have smooth or weakly-ornamented valves. Juvenile specimens, on the other hand, have valves that are almost symmetrical, with no beak-like feature and are often heavily ornamented.

We have examined the last 3 - 4 juvenile stages of 6 Bennelongia species from 5 different lineages, in order to decipher the types of external valve ornamentation and their recurrences during ontogeny and across lineages. It is clear that ornamentation is more prevalent at the early instar stages compared to the last 2 pre-adult stages, and especially when compared to the adult stage itself.

We also examined the surprising presence of a calcified inner lamella with a prominent inner list in the pre-adult stages of Bennelongia species, that is usually absent in juveniles of other ostracods, thus questioning if heterochronic processes have provided an intermediate valve morphology between the simple (normal) cypridinid juvenile state and the heavily derived and modified state of adult Bennelongia.

We discuss the possible (speculative) functionality of the ornamentation in juveniles.


Benson R.H. & MacDonald H.C. 1963. Postglacial (Holocene) ostracodes from Lake Erie. Paleontological contributions of the University of Kansas 33 (Arthropoda 4): 1-26.

Brady G.S. 1886. Notes on the freshwater Entomostraca from South Australia. Proceedings of the Zoological Society of London 54: 82-93.

Carbonel P. 1988. Ostracods and the transition between fresh and saline waters. In: De Deckker P., Colin J.P. & Peypouquet J. P. (eds) Ostracoda in the Earth Sciences: 157-173. Elsevier, Amsterdam.

Chivas A.R., De Deckker P. & Shelley J.M.G. 1983. Magnesium, strontium, and barium partitioning in nonmarine ostracode shells and their use in palaeoenvironmental reconstructions - a preliminary study. In: Maddocks R.F. (ed.) Applications of Ostracoda: 238-249. University of Houston, Geoscience Department, Houston.

Danielopol D.L., Martens K. & Casale L.M. 1990. Revision of the genus Leucocythere Kaufmann, 1892 (Crustacea, Ostracoda, Limnocytheridae), with the description of a new species and two new tribes. Bulletin van het Koninklijk Belgisch Instituut voor Natuurwetenschappen, Biologie 59 (1989): 63-94.

De Deckker P. 1981a. Ostracoda from Australian inland waters - Notes on taxonomy and ecology. Proceedings of the Royal Society of Victoria 93: 43-85.

De Deckker P. 1981b. Taxonomic Notes on Some Australian Ostracods with Description of New Species. Zoologica Scripta 10: 37-55. http://dx.doi.org/10.1111/j.1463-6409.1981.tb00483.x

De Deckker P. 1981c. Taxonomy and ecological notes of some ostracods from Australian inland waters. Transactions of the Royal Society of South Australia 105 (3): 91-138.

De Deckker P. 1982. On Bennelongia tunta De Deckker sp.nov. A Stereo-Atlas of Ostracod Shells 9 (21): 117-124.

De Deckker P., Geurts M.A. & Julia R. 1979. Seasonal rhythmites in a Lower Pleistocene lake in NE Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 26: 43-71. http://dx.doi.org/10.1016/0031-0182(79)90140-8

De Deckker P. & McKenzie K.G. 1981. Bennelongia, a new cyprididid ostracod from Australasia. Transactions of the Royal Society of South Australia 105: 53-58.

Halse S.A., Shiel R.J., Storey A.W., Edward D.H.D., Lansbury I., Cale D.J. & Harvey M.S. 2000. Aquatic invertebrates and waterbirds of wetlands and rivers of the southern Carnarvon Basin, Western Australia. Records of the Western Australian Museum, Supplement 61: 217-265.

Horne D.J. & Smith R.J. 2004. First British record of Potamocypris humilis (Sars, 1924), a freshwater ostracod with a disjunct distribution in Europe and southern Africa. Bollettino della Società Paleontologica Italiana 43 (1-2): 297-306.

Kesling R.V. 1951. The morphology of ostracod molt stages. Illinois Biological Monographs 21: 1-324.

Keyser D. 2005. Histological peculiarities of the noding process in Cyprideis torosa (Jones) (Crustacea, Ostracoda). Hydrobiologia 538: 95-106. http://dx.doi.org/10.1007/s10750-004-4940-x

Kilenyi T.I. 1972. Transient and balanced genetic polymorphism as an explanation of variable nodding in the ostracode C. torosa. Micropaleontology 18: 47-63.

King R.L. 1855. On Australian Entomostracans. Papers and Proceedings of the Royal Society of Van Diemen’s Land 3 (1): 56-75.

Lopez L.C.S. & Rios R.I. 2001. Phytotelmata community distribution in tanks of shaded and sun-exposed terrestrial bromeliads from restinga vegetation. Selbyana 22: 219-224.

Martens K. 1985. Effects of temperature and salinity on postembryonic growth in Mytilocypris henricae (Crustacea, Ostracoda). Journal of Crustacean Biology 5 (2): 258-272. http://dx.doi.org/10.2307/1547873

Martens K. 1986. Taxonomic revision of the subfamily Megalocypridinae Rome, 1965 (Crustacea, Ostracoda). Verhandelingen van de koninklijke Academie voor Wetenschappen, Letteren en Schone Kunsten, Klasse der Wetenschappen 48 (174): 1-81.

Martens K., Schön I., Meisch C. & Horne D.J. 2008. Global biodiversity of non-marine Ostracoda (Crustacea). In: Balian E., Segers H. & Martens K. (eds) Freshwater animal diversity assessment. Hydrobiologia 595: 185-193. http://dx.doi.org/ 10.1007/s10750-007-9245-4

Martens K. & Savatenalinton S. 2011. A subjective checklist of the Recent, free-living, non-marine Ostracoda (Crustacea). Zootaxa 2855: 1-79.

Martens K., Halse H. & Schön I. 2012. Nine new species of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) from Western Australia, with the description of a new subfamily. European Journal of Taxonomy 8: 1-56. http://dx.doi.org/10.5852/ejt.2012.8

Rosenfeld A. & Vesper B. 1977. The variability of the sieve-pores in recent and fossil species of Cyprideis torosa (Jones, 1850) as an indicator for salinity and palaeosalinity. In: Löffler H. & Danielopol D.L. (eds), Aspects of Ecology and Zoogeography of Recent and Fossil Ostracoda: 55 -67. Junk, The Hague.

Sars G.O. 1896. On fresh-water Entomostraca from the neighborhood of Sydney, partly raised from dried mud. Archiv for Mathematik og Naturvidenskab 18 (3): 1-81.

Shearn R., Koenders A., Halse S., Schön I. & Martens K. 2012. A review of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) species from eastern Australia, with the description of three new species. European Journal of Taxonomy 25:1-35. http://dx.doi.org/10.5852/ejt.2012.25

Smith R.J. & Martens K. 1996. On Eucypris virens (Jurine). Stereo-Atlas of Ostracod Shells 23 (14): 61-68.

Smith R.J. & Martens K. 2000. The ontogeny of the cypridid ostracod Eucypris virens (Jurine, 1820) (Crustacea, Ostracoda). Hydrobiologia 419: 31-63. http://dx.doi.org/10.1023/A:1003985908460

Smith R.J. & Kamyia T. 2005. The ontogeny of the entocytherid ostracod Uncinocythere occidentalis (Kozlov & Whitman, 1954) Hart, 1962 (Crustacea). Hydrobiologia 538: 217-229. http://dx.doi.org/10.1007/s10750-004-4965-1

Smith R.J. & Kamyia T. 2008. The ontogeny of two species of Darwinuloidea (Ostracoda, Crustacea). Zoologischer Anzeiger 247: 275-302. http://dx.doi.org/10.1016/j.jcz.2008.05.002

Turpen J.B. & Angell R.W. 1971. Aspects of molting and calcification in the ostracode Heterocypris. Biological Bulletin of the Marine Biology Laboratory 140: 331-338.

Van Morkhoven F.P.C.M. 1962. Post-Palaeozoic Ostracoda. Volume 1. Their Morphology, Taxonomy, and Economic Use. Elsevier Publishing Company, Amsterdam.

Williamson D.I. 2003. The origins of larvae. Kluwer Academic Publishers, Dordrecht, 261 pp.

How to Cite
De Deckker, P., & Martens, K. (2013). Extraordinary morphological changes in valve morphology during the ontogeny of several species of the Australian ostracod genus Bennelongia (Crustacea, Ostracoda). European Journal of Taxonomy, (36). https://doi.org/10.5852/ejt.2013.36