Five new species of cotylean flatworms (Platyhelminthes: Polycladida) from the wider Caribbean

Abstract

Five new species of cotylean flatworms belonging to the genera Pseudoceros Lang, 1884, Thysanozoon Grube, 1840, Pseudobiceros Faubel, 1984 and Maritigrella Newman & Cannon, 2000, are described from the wider Caribbean. Specific determinations are based primarily on color and color pattern. Diagrammatic reconstructions of the reproductive systems derived from serial histological sections and whole mounts are presented. In addition, a re-description of Pseudoceros pardalis Verrill, 1900 resulted in the new combination, Pseudobiceros pardalis.

When names are wrong and colours deceive: unravelling the Pseudoceros bicolor species complex (Turbellaria: Polycladida)

“…Support for inclusion into one species comes from pairwise comparisons, which reveal genetic distances of 0-0.00108. The inclusion of these specimens into P. rawlinsonae warrants an emendation to the original species description (Bolaños et al 2007).…”

“…The following were selected to represent the outgroup: four species of Prosthiostomidae (Lurymare utarum Marcus, 1952, Enchiridium periommatum Bock, 1913, Euprosthiostomum mortenseni Marcus, 1948, Prosthiostomum cynarium Marcus, 1950, two species of Pericelidae [Pericelis cata Marcus andMarcus, 1968, Pericelis orbicularis (Schmarda, 1859)], two species of Euryleptidae [Maritigrella crozieri (Hyman, 1939) M. newmanae Bolaños et al, 2007], one species representing Boniniidae (Boninia divae Marcus and Marcus, 1968), and two species of Acotylea [Imogine zebra (Verrill, 1882), Pleioplana atomata (Müller OF, 1776)]. According to Rawlinson and Litvaitis (2008), Prosthiostomidae represent the immediate sister group of a clade containing pseudocerotids and euryleptids.…”

“…A group of similarly coloured, sympatric pseudocerotid polyclads has been reported from throughout the Caribbean and from Brazil (Verrill 1901;Hyman 1939;Marcus and Marcus 1968;Newman et al 2000;Newman and Cannon 2003;Quiroga et al 2004a,b;Bolaños et al 2007;Bahia and Padula 2009). Specimens in this group may exhibit dorsal surfaces that range from black through a darker brown or brownish-red to a light brown.…”

“…A thin marginal line may or may not surround the animals. The various colour morphs have been assigned to three species, namely Pseudoceros bicolor Verrill, 1901, Pseudoceros aureolineata Verrill, 1901(emended to P. aureolineatus, Marcus, 1950, and Pseudoceros rawlinsonae Bolaños et al (2007).…”

“…The original description of P. rawlinsonae includes a white body, with a mid-dorsal, black (sometimes containing a few white speckles), very broad, branched stripe and a margin that becomes translucent towards the periphery. A narrow, bright-gold/orange line surrounds the entire animal (Bolaños et al 2007). Hence, the species fits the description of P. bicolor, but possesses the marginal line of P. aureolineatus.…”