Babakina indopacifica, SP. NOV.
Creators: name: Gosliner, Terrence M.
name: González-Duarte, Manuel M.
name: Cervera, Juan Lucas
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Flabellinidae
Babakina
Babakina indopacifica

description: BABAKINA INDOPACIFICA SP. NOV.
(FIGS 1D, 3D, 5)
Babakina festiva – Nakano, 2004: 253.
Babakina festiva – Ono, 2004: 257.
Babakina cf. festiva – Rudman, 2005b.
Babakina cf. festiva – Rudman, 2005c.
Material examined: Holotype: CASIZ 085891, one specimen, dissected, on sea grass, 1 m depth, near Dipalog, northern Mindanao, Philippine Islands, T. M. Gosliner. Paratypes: CASIZ 088572, one specimen, dissected, 14 mm alive, 18 m depth, crawling at night, Molikini Islet, Maui, Hawaiian Islands, 31.viii.1992, Pauline Fiene. CASIZ 164914, one specimen, in open at night, 1 m depth, Hekili Point, Maui, Hawaiian Islands, 3.x.2002, Cory Pittman. CASIZ 118804, one specimen, Hekili Point, Maui, Hawaiian Islands, 1 m depth, 3.x.1997, Cory Pittman. CASIZ 120655, one specimen, crawling on bottom at night, 1 m depth, Hekili Point, Maui, Hawaiian Islands, 24.x.1999, Cory Pittman. CASIZ 144040, one specimen, dissected, 5 m depth, off S coast of Gahi Island, Kerama Islands, Ryukyu Islands, Japan, 13.i.2000, Atsushi Ono. One specimen, MNCN 15.05 /46741, 12 m depth, Hachijo Island, Japan, 4.v.2005, Nishina Masayoshi. CASIZ 173035, one specimen, dissected (missing buccal mass) Station 14, 14 m depth, barrier reef edge, 14 m depth, W of Nosy Valiha, Radama Islands, Madagascar, 20.x.2005, T. Gosliner.
Distribution: This species is known from southern Japan: Kerama Islands and Hachijo Island (Nakano, 2004; Ono, 2004; and present study), the Philippines, Indonesia, Madagascar and the Hawaiian Islands (present study) and South Korea (Rudman, 2005c).
Etymology: This species is named indopacifica for its tropical Indo-Pacific distribution. The remaining three species of Babakina are temperate taxa.
External morphology: The body is elongate and slender, with a trailing posterior end of the foot (Fig. 1D). Living animals are 7–18 mm in length. The anterior margins of the foot and tentaculiform foot corners are bilabiate and slightly notched. The body colour can range from a translucent light purple to deep reddish purple. A broad opaque white patch covers most of the head between the rhinophores and the anterior margin of the head. A smaller patch may be present just behind the rhinophores in some specimens. In all specimens observed an additional opaque white patch covers the pericardial region. The relatively short cerata are thick, widest in the middle and taper distally. They are almost entirely opaque white with some bluish purple pigment visible on their posterior face. The apex is translucent white. The cerata are densely clustered and continuous throughout the length of the body, without interruption in the pericardial region. The medial area between the rhinophores and pericardial region is relatively devoid of cerata. There are approximately 15–33 diagonal rows of cerata on either side of the body. Each row contains 2–3 cerata with the innermost cerata of each row being the largest. The bright red rhinophores share a common base, are perfoliate and have up to 28–32 lamellae each. The posterior portion of the rhinophores is covered by a fine dusting of opaque white pigment that extends to the apex. The anterior face lacks opaque white and is uniformly red. The oral tentacles are relatively short, but longer than the rhinophores and have a smooth texture. They are pinkish purple basally with a band of opaque white covering the outer one-third to half of the tentacle. The tentacular anterior foot corners are short and are often held close to the body so they are not readily visible. They are pinkish purple throughout their length. The pleuroproctic anus is located ventral to the notal brim about one-third of the body length from the anterior end, ventral to the 14th-16th ceratal row. The nephroproct is anterior to the anus. The genital aperture is located below the notal brim just posterior to the rhinophore base below the seventh ceratal row.
Buccal armature: The jaws (Fig. 5A, B) are tanbrown. The masticatory border contains three rows of numerous irregularly spaced, triangular denticles. The radula formula is 18 ¥ 0.1.0 (CASIZ 085891) and 14 ¥ 0.1.0 (CASIZ 088952) in two specimens examined. The rachidian tooth (Fig. 5C, D) is broad with a wide, triangular central cusp. There are 6–12 elongate, acutely pointed denticles on either side of the central cusp in one specimen (CASIZ 088972) and 10–17 denticles in the second (CASIZ 085891). The number of denticles is not equal on either side. For example on one tooth there were 17 denticles on left side and 13 on the right side. No denticles share a common base and none bifurcates above. In some instances denticles are present on the central cusp while in other cases they are only found laterally from the cusp.
Reproductive system: It has an androdiaulic arrangement (Fig. 3D) and was examined in detail in three specimens (CASIZ 085891, CASIZ 088972, CASIZ 173035). The narrow elongate preampullary duct widens into the convoluted ampulla. The ampulla consists of one large fold and narrows again before dividing into the oviduct and vas deferens. The vas deferens widens into a glandular prostatic portion with relatively few convolutions. The prostatic portion enters the wider proximal portion of the penial sac. The penial papilla is contained within the penial sac. The unarmed penial papilla is short and conical in shape. It narrows to an acute apex and exists adjacent to the elongate, very thin bursa copulatrix. The oviduct is elongate and connects to the pyriform receptaculum seminis. The other portion of the oviduct emerges from the base of the receptaculum and, after a short distance, enters the small albumen gland. The membrane gland is about the same size as the albumen gland. The mucous gland is much larger than the other two female glands and exits ventral to the penis and bursa copulatrix.
Remarks: The specimens from the tropical Indo-Pacific can be distinguished easily from other members of Babakina. They have opaque white pigment on spindle-shaped cerata and a larger patch of opaque white on the head with an additional pigment patch on the pericardium. The remaining species have thinner, more cylindrical cerata and more elongate anterior foot corners than does B. indopacifica. This species shares some radular similarities with B. festiva. In both species, the number of denticles on either side of the radular tooth is generally unequal and some denticles are situated on the sides of the primary cusp. B. indopacifica is also distinguished by a unique combination of reproductive characters (Table 1). As in B. caprinsulensis, B. indopacifica has a short, conical penis. It is similar to B. festiva in that it has a thin, elongate rather than a short pyriform receptaculum seminis as in B. caprinsulensis and B. anadoni. However, the bursa of B. indopacifica is much smaller than that of B. festiva. Babakina indopacifica also has two unique reproductive characters. The bursa is much reduced and is almost vestigial and the vas deferens has relatively few convolutions compared with the other three species. On the basis of all of these features, the description of B. indopacifica as a new species of Babakina is supported.
description: Published as part of Gosliner, Terrence M., González-Duarte, Manuel M. & Cervera, Juan Lucas, 2007, Revision of the systematics of Babakina Roller, 1973 (Mollusca: Opisthobranchia) with the description of a new species and a phylogenetic analysis, pp. 671-689 in Zoological Journal of the Linnean Society 151 (4) on pages 678-680, DOI: 10.1111/j.1096-3642.2007.00331.x, http://zenodo.org/record/4687596