Dermatobranchus kalyptos, Gosliner & Fahey, 2011

Gosliner, Terrence M. & Fahey, Shireen J., 2011, Previously undocumented diversity and abundance of cryptic species: a phylogenetic analysis of Indo-Pacific Arminidae Rafinesque, 1814 (Mollusca: Nudibranchia) with descriptions of 20 new species of Dermatobranchus, Zoological Journal of the Linnean Society 161 (2), pp. 245-356 : 316-319

DERMATOBRANCHUS KALYPTOS SP. NOV.

( FIGS 58A , 59 , 60 )

Dermatobranchus sp. 1 Gosliner, Behrens & Valdés, 2008:308, second photo.

Type material: Holotype: CASIZ 174139 , 40 mm preserved, east side Lombok Island , Indonesia, 10 m depth, collected 23.xi.1995 by P. Fiene.

Paratypes: CASIZ 107424 , two specimens, 28–30 mm, both dissected, east side Lombok Island , Indonesia, 10 m depth, collected 23.xi.1995 by P. Fiene .

Geographical distribution: This species is known from Indonesia (present study) and possibly Australia ( Coleman, 2008, as warty Dermatobranchus ).

Etymology: The specific name kalyptos is the Greek word meaning to cover or conceal, to hide, or a covering. This is in reference to the camouflage colour pattern of this species that allows it to blend in with the substrate.

External morphology: The body shape of the living animal ( Fig. 58A ) is elongate and narrows at the posterior end. The foot does not project beyond the distinct mantle margin. The dorsum has no ridges but has irregularly-spaced dorsal humps. There are some rounded tubercles irregularly spaced along the posterior mantle sides. The oral veil projects forward. The rhinophores are situated behind the oral veil and appear to be partially joined at their inner base. They have a series of longitudinal lamellae on the rounded club. The stalk does not narrow and the club has a small projecting tip. There are visible marginal sacs along the mantle edge.

There are no longitudinal branchial or hyponotal lamellae under the mantle margin. The genital opening is situated near the oral veil. The anus is situated approximately half of the way to the posterior end of the body.

The ground colour of the dorsum and the foot is pale blue or lavender. On the mantle, there are several large patches of white and tan pigment and some raised brown areas. There are some smaller, dark brown spots scattered randomly. Around the rhinophores are mottled patches of light brown. The rhinophore stalk is opaque white with a dark line on the anterior side. The club is dark brown and the tip is white. The oral veil is white with a mix of blue and brown spots. On the ventral side of the mantle and on the foot are small blotches of dark pigment.

Buccal armature: The jaws are large and thickly cuticularized ( Fig. 59A, B ), with a thick masticatory margin and multiple rows of long, pointed denticles ( Fig. 59C ). The radular formula of one of the paratypes ( CASIZ 107424) is 40 ¥ 57.1.1.1.57 ( Fig. 59D ). The rachidian teeth ( Fig. 59E ) have a broad base with a large, pointed central cusp, which projects beyond the 14–21 flanking denticles on each side. The inner lateral tooth is claw-shaped with up to 8–14 denticles that are nearly equal in length. The next 17 lateral teeth are long and pointed with 23–27 denticles. The remaining 40 lateral teeth ( Fig. 59F ) are long, pointed hooks without denticles.

Reproductive system: The reproductive organ arrangement is androdiaulic. The hermaphroditic duct leads into the long, tubular ampulla ( Fig. 60 ). The ampulla bifurcates into the female gland mass via a short oviduct and into the very long, coiled prostate. The prostate twists and spirals several times then expands into the wide, bulbous penial sheath. From the large, round bursa, the long, narrow vaginal duct extends into the slightly wider vagina, which exits into the genital atrium adjacent to the penial sheath. Geographical distribution: This species is known only from the north coast of Papua New Guinea (present study).

Etymology: The specific name kokonas comes from the New Guinea pidgin word kokonas, for coconut, because of the resemblance of the colour and texture of the notum of this animal to the meat of the coconut. Remarks: Externally, D. kalyptos most closely resembles D. pustulosus from the Philippine Islands and Indonesia. Both species have a tuberculate dorsum and some pale blue or lavender pigment. However D. pustulosus has low, broken ridges whereas D. kalyptos does not. The rhinophores of D. pustulosus are lighter and more bulbous than those of D. kalyptos . Internal differences between these species are included in the Remarks section for D. pustulosus .

Figures

Figure 58. Living animals. A, Dermatobranchus kalyptos sp. nov., Lombok Island, Indonesia, photo by Pauline Fiene. B, Dermatobranchus kokonas sp. nov., CASIZ 075272, Bagabag Island, Papua New Guinea, photo by T. M. Gosliner. C, Dermatobranchus leoni sp. nov., CASIZ 167455, Mabini Luzon, Philippines, photo by Constantinos Petrinos. D, Dermatobranchus microphallus sp. nov., Flores, Indonesia, photo by Pauline Fiene. E, Dermatobranchus oculus sp. nov., Okinawa, Japan, photo by Bob Bolland. F, Dermatobranchus piperoides sp. nov., CASIZ 068708, Rempi Lagoon, Papua New Guinea, photo by T. M. Gosliner. G, Dermatobranchus phyllodes sp. nov., CASIZ 070451, Bagabag Island, Papua New Guinea, photo by T. M. Gosliner. H, Dermatobranchus phyllodes sp. nov., CASIZ 173351, Bohol, Philippines, photo by Marina Poddubetskaia.

Figure 59. Dermatobranchus kalyptos sp. nov. Buccal armature, CASIZ 107424, Lombok, Indonesia. A, jaws; B, masticatory margin; C, detail of masticatory denticles; D, entire radula; E, central portion of radula; F, middle and outer lateral teeth.

Figure 60. Dermatobranchus kalyptos sp. nov. Reproductive system, CASIZ 107424, Lombok, Indonesia. a, ampulla; bc, bursa copulatrix; fg, female gland mass; pr, prostate; ps, penial sheath; v, vagina; vd, vaginal duct. Scale bar = 3.33 mm.