Baeolidia lunaris, Carmona, Leila, Pola, Marta, Gosliner, Terrence M. & Cervera, Juan Lucas, 2014

Carmona, Leila, Pola, Marta, Gosliner, Terrence M. & Cervera, Juan Lucas, 2014, Review of Baeolidia, the largest genus of Aeolidiidae (Mollusca: Nudibranchia), with the description of five new species, Zootaxa 3802 (4), pp. 477-514 : 498-500

Baeolidia lunaris sp. nov.

LSID urn:lsid:zoobank.org:act:249BBCD0-ED70-4513-8954-BB8566ECFC0E ( Figs. 3 C, 9D, 11 E–F, 12A)

Baeolidia sp. 1: Gosliner et al. 2008, 405.

Material examined. Holotype: CASIZ 0 99221, one specimen, dissected, 10 mm in length alive, Tanzania, Mtwara Region, Mana Huanja Island, collected by Terrence M. Gosliner, 0 1 November 1994. Type locality and habitat. Mtwara Region, Mana Huanja Island, Tanzania. Found in shallow water feeding on zoanthids.

Geographical distribution. So far, only known from Tanzania (present study). Etymology. The specific name refers to the white patch present at the base of the cerata, similar to the moon (from latin: lunaris , pertaining to the moon).

External morphology ( Figs. 3 C, 12A): Body short, broad, tapering close to posterior end of foot. Foot corners rounded. Body colour translucent brownish. Fine iridescent opaque white spots over body. Rhinophores approximately equal in length to oral tentacles. Rhinophores densely covered by elongate papillae ( Fig. 3 C). Rhinophores translucent brownish with small white spots. Apex white. Oral tentacles translucent brownish short, slender, tapering near apices. Cerata moderately long, flattened, leaf-like. Cerata same colour as ground body colour, but a little bit darker. White spot on anterior side of cerata, close to base. Cerata recurved inwardly. Apex white. Cerata in one arch and four rows, leaving a distinct gap between pre and post-pericardial groups. Each group with 2–5 cerata, decreasing in size towards foot. Anus cleioproctic, below first right row. Gonopore housed among cerata of anteriormost right group.

Anatomy. Masticatory process smooth ( Fig. 11 E). Radular formula 21 x 0.1.0 ( CASIZ 0 99221, 10 mm). Radular teeth blended with 52–71 elongate, acutely pointed denticles ( Fig. 11 F). Central cusp absent. Teeth progressively smaller towards posterior radular region. Oral glands small, ovoid, delicate. Salivary glands long. Reproductive system diaulic ( Fig. 9 D). Preampullary duct widening into short ampulla. Postampullary duct dividing into oviduct and vas deferens. Vas deferens entering into wider proximal portion of penial sac with unarmed penial papilla. Receptaculum seminis rounded, short stalk connecting to short oviduct, before latter forms female glands. Vagina ventral to penis.

Remarks. Three Baeolidia species are known from Tanzania. Only B. moebii ( Eliot, 1903; Edmunds, 1970), B. salaamica ( Rudman, 1982) and B. lunaris sp. nov. (present study) have been reported in that country. In terms of colouration, B. lunaris sp. nov. differs from B. moebii and B. salaamica in several features. B. lunaris sp. nov. lacks the whitish or yellow ring usually present in B. moebii . The latter species also has a bright yellow subapical band, which does not appear in B. lunaris sp. nov.. B. salaamica lacks any traces of iridescent pigmentation, being mainly translucent white or brown. Moreover, both species, B. salaamica and B. lunaris sp. nov. differ in the shape of the radular teeth (see Figs. 7 C–D and 11E–F respectively). The radular teeth of B. salaamica are bilobed while B. lunaris sp. nov. has pectinate teeth. However, teeth of B. moebii and B. lunaris sp. nov. are very similar ( Figs. 4 A–B and 11E–F respectively). In terms of reproductive system, B. lunaris sp. nov. is the only of these three species with rounded receptaculum seminis. The main difference among these species from Tanzania is the morphology of the papillae of their rhinophores. While B. moebii and B. salaamica have rounded and short papilla, B. lunaris’ sp. nov. are clearly longer.

Regarding the remaining members of this genus, B. lunaris sp. nov. is similar to B. rieae sp. nov. and B. gracilis sp. nov. (see below) in that the three species have iridescent pigment. Neither B. rieae sp. nov. nor B. gracilis sp. nov. have a white spot at the base of the anterior side of the cerata. Additionally, the shape of the radular teeth of B. gracilis sp. nov. and B. rieae sp. nov. is different of B. lunaris’ sp. nov. . The former species have a radular teeth more bilobed and less bended than the radular teeth of B. lunaris sp. nov. (see Figs. 11 A–B, 11E–F and 13A–B respectively). Because of the lack of material properly conserved for a molecular study, we could not test the validity of this species from a molecular perspective. However, we consider that the morphological and colour characteristics presented here support the validity of Baeolidia lunaris sp. nov..

Figures

FIGURE 3. Different papillate rhinophores in Baeolidia: (A) from Rudman (1982); (B) from Gosliner (1985). Scale bars: A, 3 mm; B, 1 mm; C, 1.2 mm; D, 1.5 mm.

FIGURE 4. Scanning electron photographs. (A – B) Baeolidia moebii (CASIZ 180327): (A) Detailed view of the masticatory border; (B) Radular teeth; (C – D) Baeolidia macleayi (CASIZ 195247): (C) Detailed view of the masticatory border; (D) Radular teeth; (E – F) Baeolidia japonica (CASIZ 181357); (E) Detailed view of the masticatory border; (F) Radular teeth. Scale bars: A, 10 µm; B, 30 µm; C-D, 10 µm; E, 100 µm; F, 150 µm.

FIGURE 7. Scanning electron photographs. (A – B) Baeolidia ransoni (CASIZ 065417); (A) Detailed view of the masticatory border; (B) Radular teeth; (C – D) Baeolidia salaamica (CASIZ 184524); (C) Detailed view of the masticatory border; (D) Radular teeth. Scale bars: A, 50 µm; B, 100 µm; C, 50 µm; D, 150 µm.

FIGURE 9. Reproductive system. (A) Baeolidia salaamica, specimen from Japan (CASIZ 184525); (B) Baeolidia rieae sp. nov., specimen from Japan (CASIZ 184525); (C) Baeolidia variabilis sp. nov., specimen from the Philippines (CASIZ 177715); (D) Baeolidia lunaris sp. nov., specimen from Tanzania (CASIZ 099221). Scale bars: A – D, 0.5 mm. Abbreviations: am, ampulla; fgm, female gland mass; ps, penial sac; rs, receptaculum seminis; va, vagina; vd, vas deferens.

FIGURE 11. Scanning electron photographs. A, B, Baeolidia rieae sp. nov. (CASIZ 184525); (A) Detailed view of the jaw; (B) Radular teeth; (C – D) Baeolidia variabilis sp. nov. (CASIZ 177715); (C) Detailed view of the masticatory border; (D) Radular teeth; (E-F) Baeolidia lunaris sp. nov. (CASIZ 099221); (E) Detailed view of the masticatory border; (F) Radular teeth. Scale bars: A, 30 µm; B, 100 µm; C, 2 µm; D, 10 µm; E, 10 µm; F, 20 µm.