Suborder ASELLOTA Latreille, 1802
Compiler and date details
31 January 2025 - Gary C. B. Poore
April 2011 - Kelley Merrin, Museum Victoria, Melbourne, Victoria
1 January 2002 - Gary C. B. Poore & Helen M. Lew Ton (Poore, G.C.B., 2002)
- Asellota Latreille, P.A. 1802. Histoire Naturelle, Générale et Particulière des Crustacés et des Insectes. Ouvrage faisant suite à l’histoire naturelle générale et particulière, composée par Leclerc de Buffon, et rédigée par C.S. Sonnini, membre de plusieurs sociétés savantes. Familles naturelles des genres. Tome troisième. Paris : F. Dufart xii + 13–467 + [1] pp. [An "X" (title page = 1802)] [41].
Introduction
The Asellota Latreille, 1802 are a diverse group of mostly small isopods inhabiting most marine environments but extremely abundant and diverse in the deep-sea (Wolff, 1962; Hessler et al., 1979) or in cold waters (Kaiser et al., 2007). In deep waters most are benthic, associated with soft sediments, but some are wholely or partially mesopelagic (Osborn, 2009). Asellotes also associate with subtidal rocky or coral reefs. Some inhabit fresh water (superfamily Aselloidea not present in Australia).
Asellota have specialised reproductive structures that distinguish them from all other isopods. Pleonites 4 and 5, and often pleonite 3 are fused to the pleotelson making an enlarged posterior segment. Pleonites 1 and 2 are vestigial. Either pleopods 1, 2 or 3 are fused to form an operculum covering the remaining pleopods. In the male pleopods 2 form a specialised copulatory apparatus involving enlarged peduncles, a folded endopod and sturdy exopod. Four superfamilies are recognised but may not be monophyletic (Wilson, 1987; Wägele, 1989; Brusca & Wilson, 1991; Just & Poore, 1992): Aselloidea Latreille, 1802; Gnathostenetroidoidea Kussakin, 1967; Janiroidea G. O. Sars, 1897; and Stenetrioidea Hansen, 1905. One family, Vermectiadidae, thought to be the most primitive asellote, displays a mixture of features of each superfamily (Just and Poore, 1992) which led to uncertainty about the relationships between the four accepted superfamilies.
Wolff (1962) provided a useful practical key to families and many genera but is well out of date. Poore et al. (1994) listed several asellote families (in addition to those now described from the Australian fauna) from off southeastern Australia.
Diagnosis
Head-pereonite 1 usually free. Dorsal pereopodal coxal plates absent. At least pleonites 4–6, sometimes pleonites 1–3 fused into pleotelson. Pleotelson underside flat, without ventrolateral ridges (pleopods not enclosed laterally). Penial processes at bases of pereopod 7. Mandibular lacinia mobilis present on both sides; molar usually a cylindrical process with triturative flat end; palp usually present. Maxilla trilobed. Maxillipedal endite reaching at least distal margin of palp article 2, usually distally truncate and setose. Pereopods 1–7 similar, directed more or less laterally. Pleopodal exopods biarticulate. Pleopod 1 uniramous in male, sometimes interacting with groove on pleopod 2, absent in female. Pleopod 2 biramous in male, endopod modified as complex gonopod; uniramous or pair fused as operculum in female. Pleopod 3 biramous (uniramous in Vermectiadidae); endopod more or less oval or rectangular, rounded distally. Telsonic region of pleotelson short, anus situated posteriorly on pleotelson. Uropod terminal; peduncle not operculate; rami terminal.
General References
Brusca, R.C. & Wilson, G.D.F. 1991. A phylogenetic analysis of the Isopoda with some classificatory recommendations. Memoirs of the Queensland Museum 31: 143-204
Hessler, R.R., Wilson, G. & Thistle, D. 1979. The deep-sea isopods: a biogeographic and phylogenetic overview. Sarsia 64: 67-76
Just, J. & Poore, G.C.B. 1992. Vermectiadidae, a new primitive asellote isopod family with important phylogenetic implications. Journal of Crustacean Biology 12: 125-144
Kaiser, S., Barnes, D.K.A. & Brandt, A. 2007. Slope and deep-sea abundance across scales: Southern Ocean isopods show how complex the deep sea can be. Deep Sea Research Part II: Topical Studies in Oceanography 54: 1776-1789
Osborn, K.J. 2009. Relationships within the Munnopsidae (Crustacea, Isopoda, Asellota) based on three genes. Zoologica Scripta 38: 617-635
Poore, G.C.B., Just, J. & Cohen, B.F. 1994. Composition and diversity of Crustacea Isopoda of the southeastern Australian continental slope. Deep-Sea Research 41: 677-693
Poore, G.C.B. & Just, J. 1990. Pseudojanira investigatoris, new species from southern Australia, second species in the Pseudojaniridae (Isopoda: Asellota) with new morphological information and interpretations. Journal of Crustacean Biology 10: 520-527
Wägele, J.W. 1989. Evolution und phylogenetisches System der Isopoda. Stand der Forschung und neue Erkenntnisse. Zoologica (Stuttgart) 140: 1-262
Wilson, G.D.F. 1987. The road to the Janiroidea: comparative morphology and evolution of the asellote isopod crustaceans. Zeitschrift für Zoologische Systematik und Evolutionsforschung 25: 257-280
Wilson, G.D.F. 1994. A phylogenetic analysis of the isopod family Janiridae (Crustacea). Invertebrate Taxonomy 8: 749-766
Wolff, T. 1962. The systematics and biology of bathyal and abyssal Isopoda Asellota. Galathea Report 6: 1-320, pls I-XIV
History of changes
| Published | As part of group | Action Date | Action Type | Compiler(s) |
|---|---|---|---|---|
| 13-Mar-2025 | CRUSTACEA Brünnich, 1772 | 29-Jan-2025 | MODIFIED | Dr Gary Poore |
| 05-Aug-2022 | 05-Mar-2012 | MODIFIED | ||
| 05-Aug-2022 | 05-May-2011 | MODIFIED | ||
| 05-Aug-2022 | 29-Jun-2010 | MODIFIED | ||
| 12-Feb-2010 | (import) |