Discodoris, BERGH, 1877

Valdés, Ángel, 2002, A phylogenetic analysis and systematic revision of the cryptobranch dorids (Mollusca, Nudibranchia, Anthobranchia), Zoological Journal of the Linnean Society 136 (4), pp. 535-636 : 565

GENUS DISCODORIS BERGH, 1877

Discodoris Bergh, 1877a: 518 . Type species: Discodoris boholiensis Bergh, 1877 , by subsequent designation by O’Donoghue (1926).

Fracassa Bergh, 1878a: 598 . Type species: Fracassa zibethina Bergh, 1878 , by monotypy, syn. nov.

Erythrodoris Pruvot-Fol, 1933: 133 . Type species: Erythrodoris dollfusi Pruvot-Fol, 1933 , by monotypy, syn. nov.

Tayuva Marcus & Marcus, 1967b: 191–192 . Type species: Tayuva ketos Ev. Marcus & Er. Marcus, 1967 , by original designation, syn. nov.

Diagnosis

Dorsum covered with simple tubercles, stiffened by integumentary spicules, which occasionally protrude from the dorsal surface in an irregular fashion. Head with two conical oral tentacles. Anterior border of the foot grooved and notched. Labial cuticle armature with rodlets. Radula composed of simple, hamate teeth. The outermost teeth may be simple or denticulate. Reproductive system with a flattened, granular prostate, having two well differentiated regions. Penis and vagina devoid of hooks. Vestibular or accessory glands absent.

Remarks

Bergh (1877b) introduced the genus Discodoris based on Doris granulata Ehrenberg, 1831 , Doris crucis Mörch, 1863 , Doris pardalis Alder & Hancock, 1864 , Doris concinna Alder & Hancock, 1864 , Doris fragilis Alder & Hancock, 1864 , and eight hitherto undescribed species: Discodoris boholiensis , D. meta , D. cebuensis , D. notha , D. muta , D. modesta and D. schmeltziana . Bergh (1877a) described these species, and at the same time reproduced the original description of the genus Discodoris . O’Donoghue (1926) subsequently designated Discodoris boholiensis Bergh, 1877 as the type species. Bergh’s (1877a) paper was published in December 1877 (see Winckworth, 1946), whereas the date of publication of Bergh (1877b) is unspecified. According to Article 21.3 ( ICZN, 1999), as the exact day of publication is not specified for any of these papers, and one of them was published in December, the date of publication of both papers is determined to be the last day of 1877. If Bergh’s (1877b) paper is selected to be the original description of the genus, D. boholiensis is not eligible to be the type species (it was undescribed). Therefore, acting as First Reviser ( ICZN, 1999: Article 24), I select Bergh’s (1877a) paper as the original description of the genus; thus D. boholiensis becomes eligible to be the type species.

Bergh (1878a) described the genus Fracassa for Fracassa zibethina Bergh, 1878 , collected from the Philippines. According to Bergh (1878a) this genus is characterized by having a quite smooth dorsum, conical oral tentacles, tripinnate branchial leaves, wide foot with the anterior border grooved and notched, presence of jaws, radular teeth simple and hamate, large differentiated prostate and penis unarmed. Re-examination of the holotype of Fracassa zibethina revealed that the dorsum of this species is covered with small, rounded simple tubercles. All these characteristics are also present in the genus Discodoris , for which Fracassa is a synonym.

Pruvot-Fol (1933) described the genus Erythrodoris based on Erythrodoris dollfusi Pruvot-Fol, 1933 , characterized by having a labial cuticle with articulated plates, elongated body and unarmed penis. These features of Erythrodoris are also present in Discodoris , and these names are regarded as synonyms. It is impossible to determine the identity of Erythrodoris dollfusi Pruvot-Fol, 1933 based on the original description and the type material is probably lost.

Marcus & Marcus (1967b) introduced the new genus Tayuva for Tayuva ketos Ev. Marcus & Er. Marcus, 1967 . The diagnosis of Tayuva included the following characteristics: pointed tentacles, labial plates with rodlets, hook-shaped radular teeth, stout penial papilla, large vestibule (atrium) stiffened by spicules and lodging the penial papilla and the vaginal aperture, nidamental opening independent from that of the atrium. This structure of the genital opening was considered ‘aberrant’ by Marcus & Marcus (1967b) and they could not find another genus that could ‘receive’ that species. In fact, this anatomical arrangement is present in all species of cryptobranch dorids. The combination of the characters described above and simple dorsal tubercles indicates that Tayuva ketos clearly belongs to the genus Discodoris ; thus Tayuva is a junior synonym of Discodoris .