Baeolidia scottjohnsoni, 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 : 502-503

Baeolidia scottjohnsoni sp. nov.

LSID urn:lsid:zoobank.org:act:EDE11CBD-6EE9-43D1-9970-158C 1FEB 2E1A ( Figs. 3 C, 12C, 13C–D, 14C)

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

Material examined. Holotype: CASIZ 184503, one specimen, dissected, 12 mm in length alive, Marshall Islands, Kwajalein Atoll, Enewetak Pinnacle, collected by Scott Joshnson, 11 October 2010. Paratype: CASIZ 180341, one specimen, dissected, 12 mm in length alive, Hawaii, Maui, Wahikuli, collected by Pauline Fiene, 30 November 2003.

Type locality and habitat. Enewetak Pinnacle, Kwajalein Atoll, Marshall Islands. Found in 10 m of water over Caulerpa .

Geographical distribution. So far, only known from the Marshall Islands and the Hawaiian Islands (present study).

Etymology. This species is dedicated to Scott Johnson who kindly provided us with abundant material from the Marshall Islands, including specimens of this new species.

External morphology ( Figs. 3 C, 12C): Body short, broad, tapering close to posterior end of foot. Foot corners tentaculiform. Body brownish. Bright white spots over head, dorsum and foot. White spots over notum form almost a continuous patch from pericardial area to posterior end of foot, excluding ceratal insertions. Iridescent blue pigmentation over white spots, more evident on those parts of dorsum where groups of cerata from both sides are closer as well as close to ceratal insertion. Rhinophores, oral tentacles and foot corners brownish with bright white spots. Rhinophores approximately same length of oral tentacles. Rhinophores with elongated papillae ( Fig. 3 C). Distal papillae whiter. Apex white. Oral tentacles with white spots. Cerata moderately short, flattened, leaf-like. Cerata slightly recurved inwards. Cerata brown with white spots on posterior side. Double subapical band on anterior side of cerata. Upper half of cerata white; second half iridescent blue that may reach their base. Orange or light ochre patch may be found on distal part of posterior side of cerata, being overlaid by bright ochre reticulate. Latter converges on apex. Apex with minute white ring. Cerata in two arches and two rows, leaving a distinct gap between pre and post-pericardial groups. Each group with 2–4 cerata, decreasing in size towards foot. Cleioproctic anus within second right arch. Genital aperture placed within anteriormost arch on right.

Anatomy. Masticatory process smooth ( Fig. 13 C). Radular formula 14 x 0.1.0 (CASIZ 184503, 12 mm). Radular teeth slightly bilobed with 25 moderately broad and acutely pointed denticles on each side of the small and elongate central cusp ( Fig. 13 D). Oral glands small, delicate (spongy), elongate. Salivary glands absent.

Reproductive system diaulic ( Fig. 14 B). Preampullary duct widening into ampulla. Postampullary duct dividing into oviduct and vas deferens. Vas deferens moderately long vas deferens inserting into wider proximal portion of penial sac with unarmed penial papilla. Receptaculum seminis huge, folded, short stalk connecting to short oviduct, before latter forms female glands. Vagina ventral to penis.

Remarks. Excluding Baeolidia japonica , B. scottjohnsoni sp. nov. is easily distinguishable from other members of the genus due to its colouration and the shape and size of its receptaculum seminis. However, the brownish colour pattern of B. japonica has some resemblances with B. scottjohnsoni sp. nov.. Both species have brownish body colour, with white spots all over the notum and a blue band on the posterior side of the cerata. Furthermore, both species have a huge receptaculum seminis ( Figs. 6 C and 14B). Nevertheless, the molecular phylogenetic analysis conducted by Carmona et al. (2013) (see Fig. 1 ) clearly illuminated the presence of distinct cryptic species that are separated by some morphological differences. The blue pigment over the notum of B. scottjohnsoni sp. nov., differences in the radular morphology (denticles of B. scottjohnsoni sp. nov. are broader than those of B. japonica ), and the folded receptaculum seminis of B. scottjohnsoni sp. nov. distinguish these species.

Carmona et al. (2013) studied this species from a molecular approach ( 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 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 6. Reproductive system. (A) Baeolidia moebii, specimen from Mozambique (MNCN 15.05 / 63447); (B) Baeolidia macleayi, specimen from Australia (CASIZ 195247); (C) Baeolidia japonica, specimen from Marshall Islands (CASIZ 181357); (D) Baeolidia ransoni, specimen from the Philippines (CASIZ 186209). 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 13. Scanning electron photographs. (A – B) Baeolidia gracilis sp. nov. (CASIZ 083766); (A) Detailed view of the masticatory border; (B) Radular teeth; (C – D) Baeolidia scottjohnsoni sp. nov. (CASIZ 184503); (C) Detailed view of the masticatory border; (D) Radular teeth. Scale bars: A, 3 µm; B, 10 µm; C, 50 µm; D, 100 µm.

FIGURE 14. Reproductive system. (A) Baeolidia gracilis sp. nov., specimen from the Philippines (CASIZ 083766); (B) Baeolidia scottjohnsoni sp. nov., specimen from Marshall Islands (CASIZ 184503). Scale bars: A, 0.5 mm; B, 1 mm. Abbreviations: am, ampulla; fgm, female gland mass; ps, penial sac; rs, receptaculum seminis; v, vagina; vd, vas deferens.