Pseudoceros laingensis Newman and Cannon, 1998
Type material location
The holotype is a whole mount of an entire specimen and the paratype is a set of serial histological sections deposited at the Queensland Museum in Brisbane, Australia.
The diagnostic character for this species is the cream background with scattered purple spots.
External anatomy: Cream background with widely spaced scattered purple spots. Each spot is formed by microdots, denser in the middle with fine dots outwards. The ventral side is cream. Pseudotentacles are formed by simple folds of the anterior margin with small scattered pseudotentacular eyes on the margin. A horseshoe shaped cerebral cluster with about 100 eyespots. A big and wide pharynx formed by elaborated folds.
Internal anatomy: The male system is formed by branched vas deferens, a rounded oblong seminal vesicle connected to a long and coiled ejaculatory duct, a large oval prostatic vesicle and a long pointed, and narrow cuticular stylet housed in a deep and voluminous antrum. The female antrum is deep and wide with a narrow and short vagina surrounded by the cement glands.
Ecology and Distribution
This species has been found in Laing Island, Hansa Bay in Papua New Guinea.
Evolution and Systematics
This species was included into the group 4, characterized by spots and dots, according to the categorization based on the color and color pattern made by Newman & Cannon (1994), and modified for the same authors (Newman & Cannon, 1998). Within this group, only P. concinnus is cream with spots; however, the spots are blue and restricted to the margin not purple and scattered over the entire dorsal surface. According to the description made by Newman & Cannon (1998), this species has two prostatic vesicles which is very unusual for this genus. Although the authors clarified that this could be a teratology, it is necessary to collect more specimens to confirm this feature. Analyzing the pictures of the histological sections of the type material, it seems like the prostatic vesicle can be observed from different cut planes with different shape and size but it is the same prostatic vesicle.
Newman, L.J. & Cannon, L.R.G (1998) Pseudoceros (Platyhelminthes: Polycladida) from the Indo-Pacific with Twelve New Species from Australia and Papua New Guinea. The Raffles Bulletin of Zoology, 46(2): 293-323.