Dermatobranchus phyllodes, 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 : 327-331

publication ID	https://doi.org/ 10.1111/j.1096-3642.2010.00649.x
persistent identifier	https://treatment.plazi.org/id/761B2D60-4824-E207-0978-F965FD623E5F
treatment provided by	Valdenar
scientific name	Dermatobranchus phyllodes
status	sp. nov.

Treatment

DERMATOBRANCHUS PHYLLODES View in CoL SP. NOV.

( FIGS 58G, H View Figure 58 , 69–71 View Figure 69 View Figure 70 View Figure 71 )

Dermatobranchus sp. , lobed Dermatobranchus Coleman, 2008: 121 View in CoL .

Dermatobranchus sp. 2 Gosliner, Behrens & Valdés, 2008: 308, above bottom photo.

Geographical distribution: This species is known only from Indonesia, the Philippine Islands, and Papua New Guinea (present study), and the Solomon Islands ( Rudman, 2001).

Etymology: The specific name phyllodes is from the Greek word meaning ‘leaflike: chlorophyll’ in reference to the distinctive leaf-like appearance of this species’ dorsum.

Dermatobranchus sp. 6 Rudman, 2001 .

Type material: Holotype: CASIZ 174164 , 40 mm preserved, Christmas Bay , Bagabag Island, off Madang, Papua New Guinea, 7 m depth, collected 10.ii.1988 by T. M. Gosliner . Paratypes: CASIZ 070451 , four specimens, one dissected, Christmas Bay , Bagabag Island, off Madang, Papua New Guinea, 7 m depth, collected 10.ii.1988 by T. M. Gosliner . CASIZ 174165 , two specimens, 27, 29 mm preserved, one dissected, Pamilacan Island , Philippine Islands, 6–37 m depth, collected 11.vi.2004 by T. Gosliner , Y. Camacho, J. Templado, M. Malaquias, M. Poddubetskaia . CASIZ 084278 , one specimen, 11 mm, dissected, Devil’s Point , Batangas, Luzon Island, Philippine Islands, 4 m depth, collected 23.ii.1992 by M. Miller . CASIZ 070290 , one specimen, 8 mm, dissected, Manado , Sulawesi, Indonesia, 12 m depth, collected 20.v.1989 by P. Fiene (M75) . CASIZ 078587 , one specimen, 14 mm, Bunaken Island , Manado, Sulawesi, Indonesia, 5 m depth, collected 21.v.1991 by P. Fiene (M75) . CASIZ 173351 , two specimens, 45 mm preserved, Pamilacan Island , Philippine Islands, 10–41 m depth, collected 7.vi.2004 by T. Gosliner , Y. Camacho, J. Templado, M. Malaquias, M. Poddubetskaia . CASIZ 174166 , three specimens, 29, 30, 40 mm preserved, Pamilacan Island , Philippine Islands, 2–4 m depth, collected 11.vi.2004 by T. Gosliner , Y. Camacho, J. Templado, M. Malaquias, M. Poddubetskaia . CASIZ 083872 , two specimens, 4–8 mm preserved, Devil’s Point , south-west of Maricaban Island, Batangas Province, Luzon Island, Philippine Islands, no depth recorded, collected 26.iii.1992 by T. Gosliner .

External morphology: The body shape of the living animal ( Fig. 58G, H View Figure 58 ) is elongate, flattened, and narrows at the posterior end. The foot projects only slightly beyond the distinct mantle margin. There is a series of deep dorsal ridges nearly perpendicular to the mantle edge, giving the dorsum a distinct leaf-like appearance. The oral veil extends forward and has blunt corners and often is notched medially. The widely spaced rhinophores are situated behind the oral veil. They have a series of longitudinal lamellae on the rounded club. The stalk does not narrow noticeably. Marginal sacs are visible along the mantle edge. There are no branchial or hyponotal lamellae. The genital opening is on the right side of the body, near the anterior of the body. The anus is situated approximately one third of the way from the anterior end to the posterior end of the body.

The ground colour of the dorsum, the oral veil, and the foot is pale green and pinkish blotches are also prevalent. There are dark green speckles and spots of various sizes scattered randomly on the dorsum. There is a U-shaped band of dark green pigment at the anterior third of the notum. The rhinophore stalk is white and the club is dark. The oral veil is opaque white with dark spots along the anterior margin and a pale orange edge. The foot margin has small dark speckles.

Buccal armature: The jaws are large and thickly cuticularized ( Figs 69A View Figure 69 , 70A View Figure 70 ), with a thick masticatory margin and multiple rows of pointed denticles ( Figs 69B View Figure 69 , 70B View Figure 70 ). The radular formulae of four paratypes are: (CASIZ 070451) 32 ¥ 99.1.99 ( Fig. 69C View Figure 69 ), (CASIZ 174165) 32 ¥ 85.1.85 ( Fig. 70C View Figure 70 ), (CASIZ 082278) 16 ¥ 39.1.39, and (CASIZ 070290) 21 ¥ 50.1.50. The rachidian teeth ( Figs 69D View Figure 69 , 70D View Figure 70 ) have a narrow base with a large, projecting, hookshaped, pointed central cusp that has no denticles on either side, although on some teeth there are three grooves on each side of the central cusp. The next 39–99 lateral teeth are long, pointed hooks with no denticles ( Figs 69E, F View Figure 69 , 70E, F View Figure 70 ).

Reproductive system: The reproductive organ arrangement is androdiaulic. The elongate hermaphroditic duct leads into the wide, thick, tubular ampulla ( Fig. 71 View Figure 71 ). The ampulla bifurcates into the female gland mass, via a short oviduct and into the short, curved prostate. The prostate expands into the wide, bulbous penial sheath. From the large, round bursa copulatrix the short, narrow vaginal duct leads to the wider vagina. The vagina exits into the genital atrium next to the penial sheath.

Remarks: Externally, this species does not closely resemble any other Dermatobranchus . No other species has the nearly perpendicular, deep dorsal ridges or the leaf-green background colour. Dermatobranchus funiculus from Okinawa and the Philippines has dorsal ridges that angle towards the mantle margin, but that species has a mid-dorsum longitudinal ridge, lacking in D. phyllodes . The background colour of these two species is very different. Dermatobranchus phyllodes is deep green with dark green and black spots, whereas D. funiculus has a white, blue or rust ground colour with blue-grey spots. Both species have a pale orange oral veil edge.

The radula of these two species is very different. Dermatobranchus phyllodes ( Figs 69 View Figure 69 , 70 View Figure 70 ) has a broad radula with a radular formula of 21–32 ¥ 39–99.1.39– 99, whereas that of D. funiculus ( Figs 54–56 View Figure 54 View Figure 55 View Figure 56 ) is 31–34 ¥ 4.2.1.1.1.2.4.

The reproductive system of these two species is somewhat similar in that both have a bulbous penial sheath, although that of D. funiculus ( Fig. 57 View Figure 57 ) is much longer, as is the prostate.

Another species with ridges angling towards the notal margin is D. diagonalis , but in this species there is no wide medial area devoid of ridges. The radular morphology of D. phyllodes is unique amongst species of Dermatobranchus . It is the only species where all lateral teeth lack denticles. In contrast, D. diagonalis has a denticulate inner lateral tooth as in D. otome , D. striatus , D. albus , and D. oculus .