Dermatobranchus dendronephthyphagus, 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 : 299

publication ID	https://doi.org/ 10.1111/j.1096-3642.2010.00649.x
persistent identifier	https://treatment.plazi.org/id/761B2D60-4840-E268-0AB7-FC04FAC43AE8
treatment provided by	Valdenar
scientific name	Dermatobranchus dendronephthyphagus
status	sp. nov.

Treatment

DERMATOBRANCHUS DENDRONEPHTHYPHAGUS View in CoL SP. NOV. ( FIGS 30H View Figure 30 , 42A View Figure 42 , 43 View Figure 43 , 44 View Figure 44 )

Dermatobranchus sp. 15 Gosliner, Behrens & Valdés, 2008: 313, above bottom photo.

Dermatobranchus nigropunctatus Baba 1949 ( Rudman, 2005) View in CoL , misidentification.

Type material: Holotype. CASIZ 115751 , dissected, Horseshoe Cliffs , 1 km west-north-west of Onna Village, Okinawa, Ryukyu Islands, Japan (26°30.00′N, 127°57.90′E), 43 m depth, collected 13.xii.1996 by R. F. Bolland. GoogleMaps

Geographical distribution: This species is known from southern Japan and probably also from New South Wales, Australia ( Rudman, 2005).

External morphology: The body shape of the living animal ( Figs 30H View Figure 30 , 42A View Figure 42 ) is elongate, but broad, slightly flattened, and narrows at the posterior end. The foot does not project beyond the mantle margin. The dorsum has approximately 14 well-elevated, longitudinal ridges on either side of the midline that may further branch posteriorly. The oral veil is large and expansive with rounded corners. The well-separated, bulbous rhinophores are situated behind the oral veil. They have a series of longitudinal lamellae on the rounded club, which has a small rounded apex. The stalk does not narrow noticeably. There are noticeable marginal sacs along the mantle edge.

There are no branchial or hyponotal lamellae under the mantle margin. The genital opening is situated in the anterior quarter of the body. The anus is situated approximately half of the way to the posterior end of the body.

The ground colour of the dorsum is white with a series of dark brown to black lines situated between the dorsal ridges. There are areas of denser dark pigment scattered over the surface of the notum. The oral veil has a series of large black spots that are more diffuse around the margins. There is a marginal yellow-orange band on both the notum and the oral veil. The rhinophore stalk is white with black pigment and the club is white with black pigment on the lamellae. The tips of the rhinophores are white.

Buccal armature: The shape of the buccal mass is broad and highly muscular. The jaws are large and thickly cuticularized ( Fig. 43A View Figure 43 ), with a thick masticatory margin. The masticatory margin is irregular, with a few rounded tubercles ( Fig. 43C View Figure 43 ). The radular formula is 42 ¥ 85.1.1.1.85 ( Fig. 43B View Figure 43 ). The rachidian teeth ( Fig. 43E View Figure 43 ) are narrow with an elongate, bluntly pointed central cusp that extends beyond the basal portion, which lacks any basal denticles. The first lateral tooth ( Fig. 43E View Figure 43 ) is elongate, with an elongate cusp. No basal denticles are present. The middle and outer lateral teeth ( Fig. 43D, E View Figure 43 ) are elongate and curved and all teeth are smooth and devoid of denticles.

Reproductive system ( Fig. 44 View Figure 44 ): The ampulla is thick and simply curved. It bifurcates to the large female gland mass via a short oviduct and to the vas deferens. The majority of the female gland mass is composed of the mucous gland whereas the membrane and albumen glands are much smaller. The prostatic portion of the vas deferens is narrow and slightly convoluted and enters the cylindrical penial sheath. Within the penial sheath, the penis is elongate terminating in a rounded apex. Adjacent to the penis is the wide vagina, which curves and narrows and terminates in a relatively large, spherical bursa copulatrix.

Remarks: Externally, D. dendronephthyphagus resembles D. striatus with its dark brown to black lines and mottling. However, D. striatus has orange pigment on its rhinophores and a series of dark brown concentric arches on the oral veil, whereas D. dendronephthyphagus has a series of black mottlings. More significantly, the jaws and radula of these species differ markedly. In D. striatus , the jaws have a well-developed masticatory margin with several rows of well-developed denticles ( Fig. 28B View Figure 28 ), whereas in D. dendronephthyphagus the masticatory margin and black pigment (see Remarks for D. leoni ). These three species also have denticles on the rachidian and inner lateral teeth that are absent in D. dendronephthyphagus . In the Remarks section for D. caeruleomaculatus it was noted that both that species and D. dendronephthyphagus have similarly elongated narrow cusps on their rachidian teeth, but D. caeruleomaculatus differs in having basal denticles on the rachidian teeth. Other reproductive differences between the two species are also noted.