Pyura doppelgangera, Rius & Teske, 2013

Rius, Marc & Teske, Peter R., 2013, Cryptic diversity in coastal Australasia: a morphological and mitonuclear genetic analysis of habitat-forming sibling species, Zoological Journal of the Linnean Society 168 (3), pp. 597-611 : 605

PYURA DOPPELGANGERA SP. NOV.

Although a difference exists regarding the maximum body size of these closely related species, they are indistinguishable externally, and it is therefore necessary to dissect them and compare internal structures. The morphological characters that distinguish these species were subtle and required the dissection of a large number of individuals to define boundaries of variability of each morphological character. The dorsal tubercle is different – smooth in P. doppelgangera ( Fig. 3A, B) and ‘granulated’ in P. praeputialis ( Fig. 3F, G). The anus has no defined lobes (and no protruded ‘lip’) in P. doppelgangera ( Fig. 3D, E), whereas P. praeputialis always has lobes (and a protruded ‘lip’) ( Fig. 3I, J). The gut of P. praeputialis has a characteristic long secondary loop that generally curves sharply ( Fig. 3H), whereas P. doppelgangera has a short secondary loop that never curves sharply, if it is present at all ( Fig. 3C). The gonoduct on the left side is clearly separated from the anal aperture in P. doppelgangera ( Fig. 3E), whereas in P. praeputialis , the gonoduct aperture is below the anus.

Heller (1878) described two similar species: Cynthia stolonifera from South Africa and C. praeputialis from Australia, which were later both considered to be of the genus Pyura ( Millar, 1966) . Subsequently, Monniot & Bitar (1983) compared specimens from Morocco, Chile, and Australia. The first one corresponded to P. herdmani , but the other two were P. praeputialis , as is evident from the characteristic shape of P. praeputialis ’ digestive track with a secondary gut loop that curves sharply, something that is not found in P. doppelgangera . As previous taxonomists have described in detail specimens of the large form ( P. praeputialis ), we considered it appropriate to describe the small form as P. doppelgangera .