Baeolidia rieae, 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 : 494-497

Baeolidia rieae sp. nov.

LSID urn:lsid:zoobank.org:act:35 F88299 -66D8-4726-8796-410D907D86F8 ( Figs. 9 B, 10A, 11A–B).

Baeolidia sp. B: Carmona et al. 2013, 6.

Material examined. Holotype: CASIZ 184525, one specimen, dissected, 3 mm in length preserved, Japan, Amami-Ohoshima Island, collected by Rie Nakano, 0 6 March 2010.

Type locality and habitat. The Amami-Ohoshima Island, Japan. Found in 7 m of water close to green zoanthids.

Geographical distribution. So far, only known from Japan (present study). Etymology. This species is named after Rie Nakano who kindly provided us material from Japan, including this new species.

External morphology ( Fig. 10 A): Body short, broad, tapering close towards posterior end of foot. Foot corners rounded. Body colour translucent. Dark ochre and pearly white pigmentation over notum. Rhinophores same colour as ground body colour with inconspicuous papillae. Apex pearly white. Cerata large, flattened, almost leaf-like. Cerata light ochre with pearly white, dark ochre and iridescent green pigmentation. Cnidosacs white. Cerata in one arch followed by three rows, leaving a distinct gap between pre and post-pericardial groups. Each arch with 2–5 cerata, decreasing in size towards the foot. Anus cleioproctic, behind first right row. Gonopore behind the anteriormost row on right.

Anatomy. Ornamentation of masticatory border could not be determined ( Fig. 11 A). Radular formula 20 x 0.1.0 ( CASIZ 184525, 3 mm). Radular teeth bilobed with 31–39 elongate, acutely pointed denticles on either side of minute central cusp ( Fig. 11 B). Teeth progressively smaller towards posterior region of radula. Oral glands small, spongy, dorso-laterally to buccal bulb. Salivary glands absent.

Reproductive system diaulic ( Fig. 9 B). Preampullary duct widening into moderately long ampulla. Postampullary duct dividing into oviduct and vas deferens. Vas deferens short, penetrating into wider proximal portion of the penial sac with unarmed penial papilla. Receptaculum seminis bean-shaped, short stalk connecting to short oviduct, before latter forms female glands. Vagina ventral to penis.

Remarks. Baeolidia rieae sp. nov. is clearly distinguishable from other members of the genus by its conspicuous iridescent pigmentation. Only Baeolidia lunaris sp. nov. and Baeolidia gracilis sp. nov. (see below) have this kind of pigment. Nevertheless, in B. lunaris sp. nov., the cerata have a completely different colouration and a very characteristic white spot on their bases. In addition, the body colour of B. gracilis sp. nov. is much darker than in B. rieae sp. nov.. B. gracilis also has larger cerata with an opaque white line on their inner margin (see below), which is absent in B. rieae sp. nov.. Anatomically, these three species are similar but some differences could be found. While the radular teeth of B. lunaris sp. nov. are pectinate, B. rieae sp. nov. and B. gracilis sp. nov. have bilobed teeth. In addition, the teeth of B. rieae sp. nov. show a minute central cusp, but B. gracilis sp. nov. only has a central notch. Baeolidia rieae sp. nov. and B. gracilis sp. nov. also differ in number of oral glands. Regarding the receptaculum seminis, there are differences in shape. While the receptaculum seminis of B. rieae sp. nov. is bean-like, in B. lunaris sp. nov. and B. gracilis sp. nov. it is rounded and ovoid respectively. Moreover, the length of the vas deferens also varies among these species, having an intermediate length in B. rieae sp. nov.. This new species was included in the molecular study by Carmona et al. (2013) ( Fig. 1 ).

Figures

FIGURE 1. Phylogeny of Baeolidia, based on Carmona et al. (2013). Names on right side of vertical bars refer to revised classification.

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 10. Photographs of the living animals. (A) Baeolidia rieae sp. nov., specimen from Japan, photo by Jum Imamoto, CASIZ 184525; (B – C) Baeolidia variabilis sp. nov.: (B) specimen from Marshall Islands, photo by Scott Johnson, CASIZ 187741; (C) specimen from the Philippines, photo by Terrence M. Gosliner, CASIZ 177715.

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.