Lasaeidae

Belongs within: Heterodonta.
Contains: Galeommatidae.

The Lasaeidae, kelly clams, are a group of small bivalves with generally thin shells. They live attached to a substrate by a byssus. Within the family, members of the genus Kellia are relatively large, up to about 15 mm in diameter, with a globose, smooth and shining shell.

The kellyclams

Published 23 April 2013

Members of the family Lasaeidae, commonly known as kellyclams, are small thin-shelled bivalves that often live in close association with larger invertebrates such as crustaceans, worms or cnidarians. The clam may be directly attached to its host or share a burrow with it; one genus, Entovalva, includes associates of sea cucumbers that live within their host’s esophagus (you can find some more details of this particular relationship here). Though the clam’s presence may not be entirely without physical effect on its host, such effects are usually minor and kellyclams are generally regarded as commensals rather than parasites. Other species live independently and may live nestled among rocks or buried in sediment; these free-living forms may possess a relatively large muscular foot for mobility. Like most bivalves, kellyclams are filter feeders; the invertebrate-commensal species are believed to take advantage of water currents created by the host to increase the effectiveness of their own feeding currents.

The family-level classification of the kellyclams has been fairly turbulent. The family has variously been known as the Lasaeidae, Erycinidae or Leptonidae, owing to confusion over which of these names has priority, while some authors have regarded them as separate families and/or recognised further segregate families Kelliidae or Montacutidae. With their small size, kellyclams have simplified a number of the characters used in classifying other bivalves, and a number of the commensal species have become modified in order to co-exist with their host. The Peregrinamor species, for instance, live attached longitudinally underneath the thorax of the ghost shrimp Upogebia; they have accordingly become low and elongate, and were until recently misclassified as mussels of the Mytilidae (note that the Lasaeidae and Mytilidae represent evolutionary lineages that first diverged some time in the Ordovician). In the broad sense, the Lasaeidae have been separated from the closely related family Galeommatidae by the fact that members of the latter have the soft body enlarged so that the shell becomes internal. However, Goto et al. (2012) established that even this distinction is not reliable, with the Galeommatidae nested and probably polyphyletic within the Lasaeidae. Also, while Goto et al. did not support recognition of the Lasaeidae as a holophyletic group, nor did they support any of the segregate families. Commensal species are scattered phylogenetically among free-living species, and host-switching has apparently happened numerous times within commensal lineages.

The Lasaeidae are hermaphrodites, and often brooders. Rather than being released as eggs, young are retained within their parent until they are released as veligers (later-stage larvae that have begun to develop a shell) or as miniature versions of the adults.

Systematics of Lasaeidae

<==Lasaeidae [Kelliidae]
    |--+--GaleommatidaeTW07
    |  `--Kellia Turton 1822TW07, F26
    |       |--K. antiqua Marwick 1926F26
    |       |--K. chironiiC64
    |       |--K. (Bornia) corbuloidesPP64
    |       |--K. cycladiaN79
    |       |--K. cycladiformis Deshayes 1850H09
    |       |--K. jacksoniana Smith 1884TW07
    |       |--K. japonicaKBC03
    |       |--K. laperousiiC64
    |       |--‘Bornia’ luticolaC64
    |       |--K. physema Melvill & Standen 1899H09
    |       |--K. rotundata Carpenter 1864C64
    |       `--K. suborbicularis (Montagu 1804) [=Mya suborbicularis]H09
    `--Lasaea Leach 1827TW07, P61
         |--*L. rubra (Montagu 1803)P61, R78 [=Cardium rubrumF27; incl. Poronia petitianaC64]
         |--L. adansoni [incl. L. rubra Popham 1940 non Cardium rubrum]BK77
         |--L. australis (Lamarck 1818)S-S90
         |--L. consanguineaF27
         |--L. hinemoa Finlay 1928P61
         |--L. maoria Powell 1933P61
         |--L. miliarisF27
         |--L. parengaensis Powell 1935P61
         |--L. rossiana Finlay 1928P61
         |    |--L. r. rossianaP61
         |    |--L. r. tutanekai Fleming 1948P61
         |    `--L. r. vexata Finlay 1928P61
         |--L. scalarisF27
         `--L. subviridisGW02
Lasaeidae incertae sedis:
  Rhectomyax undulatus (Gabb 1864)SB93
  ‘Tellina’ eburneaC64
  Cycladella papyraceaC64
  PythinaC64
    |--P. deshayesiTW76
    |--P. rugifera Carpenter 1864C64
    `--P. tasmanica Tenison Woods 1876TW76
  TellimyaC64
    |--T. bidentataC64
    |--T. substriataC64
    `--T. tumida Carpenter 1864C64
  Pristes Carpenter 1864C64
    `--*P. oblongus Carpenter 1864C64

*Type species of generic name indicated

References

[BK77] Barel, C. D. N., & P. G. N. Kramers. 1977. A survey of the echinoderm associates of the north-east Atlantic area. Zoologische Verhandelingen 156: 1–159.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

[F26] Finlay, H. J. 1926. A further commentary on New Zealand molluscan systematics. Transactions and Proceedings of the New Zealand Institute 57: 320–485.

[GW02] Giribet, G., & W. Wheeler. 2002. On bivalve phylogeny: a high-level analysis of the Bivalvia (Mollusca) based on combined morphology and DNA sequence data. Invertebrate Biology 121 (4): 271–324.

Goto, R., A. Kawakita, H. Ishikawa, Y. Hamamura & M. Kato. 2012. Molecular phylogeny of the bivalve superfamily Galeommatoidea (Heterodonta, Veneroida) reveals dynamic evolution of symbiotic lifestyle and interphylum host switching. BMC Evolutionary Biology 12: 172.

[H09] Hedley, C. 1909. The Marine Fauna of Queensland: Address by the President of Section D. Australasian Association for the Advancement of Science: Brisbane.

[KBC03] Kashin, I. A., E. V. Bagaveeva & S. F. Chaplygina. 2003. Fouling communities of hydrotechnical constructions in Nakhodka Bay (Sea of Japan). Russian Journal of Marine Biology 29: 267–283.

[N79] Norman, A. M. 1879. The Mollusca of the fiords near Bergen, Norway. Journal of Conchology 2: 8–77.

[PP64] Peres, J. M., & J. Picard. 1964. Nouveau manuel de bionomie benthique de la mer Mediterranee. Recueil des Travaux de la Station Marine d’Endoume, Bulletin 31 (27): 5–137.

[P61] Powell, A. W. B. 1961. Shells of New Zealand: An illustrated handbook 4^th ed. Whitcombe and Tombs Limited: Christchurch.

[R78] Reid, R. G. B. 1978. The systematic, adaptive and physiological significance of proteolytic enzyme distribution in bivalves. Veliger 20 (3): 260–265.

[SB93] Skelton, P. W., & M. J. Benton. 1993. Mollusca: Rostroconchia, Scaphopoda and Bivalvia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 237–263. Chapman & Hall: London.

[S-S90] Slack-Smith, S. M. 1990. The bivalves of Shark Bay, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 129–157. Western Australian Museum.

[TW07] Taylor, J. D., S. T. Williams, E. A. Glover & P. Dyal. 2007. A molecular phylogeny of heterodont bivalves (Mollusca: Bivalvia: Heterodonta): new analyses of 18S and 28S rRNA genes. Zoologica Scripta 36 (6): 587–606.

[TW76] Tenison Woods, J. E. 1876. Description of new Tasmanian shells. Papers and Proceedings of the Royal Society of Tasmania 1875: 134–162.