Lissoclinum bistratum (Sluiter, 1905)

Kott, Patricia, 2005, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (Part 3), Journal of Natural History 39 (26), pp. 2409-2479 : 2460

Lissoclinum bistratum (Sluiter, 1905)

( Figure 17E )

Didemnum bistratum Sluiter 1905, p 103 .

Lissoclinum bistratum: Kott 2001, p 298 and synonymy. Not Monniot F and Monniot C 2001, p 283 ; Kott 2004c, p 40.

Distribution

Previously recorded (see Kott 2001): Western Australia (Kimberley, Shark Bay); New South Wales (Lord Howe I., Hastings Point); Queensland (Moreton Bay to Lizard I.); Northern Territory (Darwin); Coral Sea; Caroline Is; Palau Is; New Caledonia; Philippines; Tokhara Is; Fiji; Indonesia; Singapore; Malagasy; Aden; the Red Sea. New records: Western Australia (Shark Bay, WAM 1018.89), Xmas I. (WAM 602.89).

Remarks

Colonies of the newly recorded specimen lots from Xmas I. and Western Australia are cushions, with characteristic globular spicules throughout, a single undivided testis follicle and fine Prochloron cells in the common cloacal cavity .

Although they concede that the spicules are different and that there are differences in their chemistry, Monniot F and Monniot C (2001) have not been able to separate specimens of L. bistratum from L. voeltzkowi (Michaelsen, 1920) , a junior synonym of L. timorense ( Sluiter, 1909) and claim that these two species are conspecific. These quite distinct species and their relationships are discussed in detail by Kott (2001). They are not discussed, albeit they are indeed listed, in the catalogue of valid species occurring in Australia (Kott, 1998) where Monniot F and Monniot C (2001) apparently expected the synonymy to be discussed. The two species are well characterized by many aspects of their zooids, larvae and colonies and especially by their spicules (which are dramatically different). It is not possible to assign the specimens newly recorded from the western Pacific by Monniot F and Monniot C (2001) to either of these species as insufficient information is given.

Figures

Figure 17. Scanning electron micrographs of the calcareous spicules of: (A) Trididemnum dispersum (WAM 1044.89); (B) Trididemnum nobile (SAM E3262); (C) Trididemnum pigmentatum (QM G308714); (D) Lissoclinum agriculum sp. nov. (WAM 179.93, syntypes); (E) Lissoclinum bistratum (WAM 1018.89); (F) Lissoclinum clavatum sp. nov. (SAM E3260, holotype); (G) Lissoclinum coactum (WAM 120.90); (H) Lissoclinum diversum (WAM 153.86).