Paradoris mulciber, , Marcus, 1976

Dayrat, Benoît, 2006, A taxonomic revision of Paradoris sea slugs (Mollusca, Gastropoda, Nudibranchia, Doridina), Zoological Journal of the Linnean Society 147 (2), pp. 125-238 : 199-202

PARADORIS MULCIBER ( FIGS 54 , 55 )

Percunas mulciber Marcus, 1970: 945–947 , figs 45–49.

Paradoris mulciber . – Marcus, 1976: 18–20, figs 10–14. Type material: Holotype, by original designation: Brazil [off north-eastern coasts], MA [Maranhão province], Juriaçu, 00°04′S, 44°33′W [note that the original description provided a different longitude: 44°35.05′W], 52 m depth, Sald. Est. 1750 [i.e. station 1750 of the Almirante Saldanha R/V], 6 November 1967, one specimen 21/ 12 mm, leg. Almirante Saldanha R/V [in the original description, it is unclear whether Dr Marc Kempf collected and loaned the entire collection studied by Eveline Marcus, or if he simply loaned it to her] (MZSP 41291). This label is the newest one in the jar, which also contains five older labels (some of which certainly refer to former catalogue numbers): 685; 685 2.8; 41291; Recife. Type specimen Percunas mulciber Marcus ; Percunas mulciber Marcus Sald. 1750 Exemplar tipo. According to the original description, Eveline Marcus deposited the type material of mulciber at the Department of Zoology of the University of São Paulo. The holotype is currently held by the Museum of Zoology. Marcus dissected entirely the holotype of mulciber : I could only find some pieces of the digestive system (the stomach, digestive gland) and the nervous system within the body wall; all other internal organs are missing (the left oral tentacle is partly destroyed, and the left rhinophore is also missing). No slides could be found at the MZSP (L. Simone & C. Magenta, pers. comm.).

Additional material examined: Brazil [off northeastern coasts], PE [Pernambuco province], Ponta da Pedra , 30 August 1970, one specimen 35/ 23 mm, leg. Montonchet ( MZSP 41292 ) [this specimen is a voucher ( Marcus, 1976); all the internal organs are missing; the lid of the jar also indicates ‘#1045 Marcus coll.’] .

Distribution: So far, mulciber is only known from two specimens collected from Brazil ( Marcus, 1970, 1976). Some additional specimens have been collected from the Caribbean side of Costa Rica (Y. Camacho-García, pers. comm.).

Remarks on the original description ( Figs 54B, D, F , 55B, C ): According to Marcus (1970), the preserved holotype was 19.5 mm long (i.e. approximately 25 mm alive). The colour of the live animal is unknown. Marcus’ description of the preserved dorsal notum of the holotype is brief: ‘The notum is smooth, with scattered low bosses produced by the notal glands. There are groups of small melanophores, interrupted over the yellowish glands’. The ‘low bosses’ described by Marcus clearly refer to an indecora -like granulation ( Fig. 54B, F ). Marcus (1976) later recognized that those bosses ‘are not produced by some specially large subepithelial glands’. With a dissecting microscope, I could discern some wide holes on the dorsal surface ( Fig. 54F ). The ventral surface is white. According to Marcus, there are six multipinnate branchial plumes with a smooth branchial pouch, ‘pointed’ oral tentacles, a notched upper lip of the bilabiate anterior foot margin ( Fig. 54D ), rhinophores with 15 lamellae, and crenulate rhinophoral sheaths. The stomach is free. The oral tentacles are grooved ( Fig. 54D ); I could count six branchial leaves and 15 lamellae on the right rhinophore; I am not convinced, however, that the term ‘crenulate’ is appropriate to describe the rhinophoral sheaths, which are only loosely crenulate ( Fig. 54C ). Marcus mentioned ‘two anterior and two posterior areas’ on the labial cuticle. This feature could not be verified (the jaw plates are missing) and it is difficult to know what Marcus really wanted to describe. In her re-description of mulciber, Marcus (1976) described three jaw plates: two lateral plates and an additional dorsal plate. This suggests that Marcus’ original description was erroneous and that the labial cuticle of mulciber has only three jaw plates – note that the third jaw plate should be ventral, not dorsal. According to Marcus, the radular formula was 45 × (18-0-18); all teeth are simply hamate, except for the vestigial, outermost tooth; the tooth base is ‘bipartite’. The nervous system does not present any distinguishing peculiarity ( Fig. 55B ). Marcus’ description of the reproductive system was largely incomplete: a ‘massive’ prostate, a ‘blunt, fleshy penial papilla’ that is probably the evaginable distal end of the deferent duct, a ‘cluster of multicellular glands’ that corresponds to an undetermined number of accessory glands, and three sacs with three 0.5 mm long ‘darts’. Marcus could not observe the spermatic pouches and their ducts.

Infra-specific character variation ( Figs 54A, E, G , 55A ): No major difference is noticeable between the holotype and the additional specimen described by Marcus (1976). This additional specimen, also from the north-eastern coasts of Brazil, is 35 mm long, preserved, i.e. approximately 40–45 mm long alive. The notum is entirely covered with indecora -like tubercles of unequal sizes ( Fig. 54A ). The dorsal notum is covered with irregular dark areas (due to minute black pigments), but the colour of the live animal is unknown ( Fig. 54G ). I discerned some wide holes with a dissecting microscope. Marcus mentioned several general features such as: 20 rhinophoral lamellae (pigmented with black and brown), more than one (probably two) blood glands, a free stomach, three jaw plates (two lateral plates, and an additional, dorsal one), and a radular formula of 34 × (21-0-21). The reproductive system includes ( Fig. 55A ): a massive prostate (Marcus did not mention whether it is divided into two parts), a long, convoluted deferent duct, a penial papilla; three stylet sacs and an uncertain number of accessory ‘multicellular glands’, a convoluted vaginal duct, and a spherical bursa copulatrix that is approximately five times larger than the receptaculum seminis. According to Marcus’ (1976: fig. 14) drawing of the reproductive system ( Fig. 55A ), the fertilization duct (called ‘insemination duct’ by Marcus) between the duct of the receptaculum seminis and the female gland mass is extremely long: this arrangement is unusual and needs to be verified.

Diagnostic character: Currently it is not possible to propose a diagnostic character for mulciber .

Discussion: Marcus (1976) admitted that she created the new genus name Percunas because she had overlooked the existence of Paradoris . In my opinion, the creation of the name Percunas is also a consequence of the fact that Marcus (1970) had described mulciber based on a single specimen, which yielded a vague (e.g. jaw plates) and largely incomplete (e.g. reproductive system) description.

Marcus (1976) compared mulciber with granulata and concluded that: ‘the slight differences observed in the shape of the tentacles and the jaw plates justify a distinction of the geographically widely separated species, till a re-examination of the species from Trieste supplements Bergh’s description’. These differences mentioned by Marcus are erroneous. The shape of the oral tentacles depends on preservation and cannot be used to distinguish species (especially when only one or two individuals are considered). It is unclear, however, whether Marcus considered that the slight difference between mulciber and granulata was the presence/absence of a groove in the oral tentacles (she did not describe grooved tentacles in mulciber ) or the actual shape. Also, Marcus did not explicitly explain why the jaws of these two species were different (both species have three jaw plates). I cannot agree more, however, that the differences between mulciber and indecora are ‘slight’. Indeed, mulciber and indecora cannot be distinguished. The distinction of mulciber from the Indo-Pacific Paradoris species is also jeopardized by our poor knowledge of mulciber . The latter, however, does not present the diagnostic features of dubia and liturata .

Our knowledge of mulciber is very limited. The individual variation of all morphological and anatomical features will have to be addressed. One will also need to study the relationships between mulciber and the Paradoris individuals from the eastern Atlantic, from both temperate (see indecora ) and tropical ( Eliot, 1906; Ortea, 1995) waters.

Figures

Figure 54. Paradoris mulciber. A, dorsal view, MZSP 41292, scale = 13 mm. B, dorsal view, holotype, MZSP 41291, scale = 9 mm. C, rhinophoral sheath, holotype, MZSP 41291, scale = 1.3 mm. D, anterior foot and left oral tentacle (right oral tentacle missing), holotype, MZSP 41291, scale = 2.7 mm. E, left oral tentacle, MZSP 41292, scale = 1.75 mm. F, dorsal notum with mantle holes, minute pigments, and tubercles, holotype, MZSP 41291, scale = 1.1 mm. G, dorsal notum, with mantle holes, and minute pigments, MZSP 41292, scale = 1 mm.

Figure 55. Paradoris mulciber. A, general view of the reproductive system (organs moved), MZSP 41292, after Marcus (1976: fig. 14), no scale given. B, central nervous system, dorsal view, holotype, MZSP 41291, scale = 1.3 mm. C, remaining pieces of the digestive system, holotype, MZSP 41291, scale = 2.5 mm.