Dermatobranchus funiculus, 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 : 311-316

publication ID	https://doi.org/ 10.1111/j.1096-3642.2010.00649.x
persistent identifier	https://treatment.plazi.org/id/761B2D60-4834-E216-0AD3-F9A8FE183FC9
treatment provided by	Valdenar
scientific name	Dermatobranchus funiculus
status	sp. nov.

Treatment

DERMATOBRANCHUS FUNICULUS View in CoL SP. NOV.

( FIGS 42E–H View Figure 42 , 54–57 View Figure 54 View Figure 55 View Figure 56 View Figure 57 )

Dermatobranchus sp. 9 Gosliner, Behrens & Valdés, 2008: 311, bottom photo.

Dermatobranchus sp. 18 Gosliner, Behrens & Valdés, 2008: 314, below top photo.

Dermatobranchus sp. 21 Gosliner, Behrens & Valdés, 2008: 315, top photo.

Type material: Holotype: CASIZ 177375 , subsampled for DNA, Bethlehem , Maricaban Island, Batangas Province, Luzon, Philippines (13°40.3338′N, 120°50.51166′E), 19 m depth, collected 18.iii.2008 by T. Gosliner et al GoogleMaps . Paratypes: CASIZ 177379 , one specimen, subsampled for DNA, Bethlehem , Maricaban Island, Batangas Province, Luzon, Philippines (13.672230°N, 120.841861°E), 19 m depth, collected 18.iii.2008 by GoogleMaps T. Gosliner et al . CASIZ 177377 , one specimen, dissected, Bethlehem , Maricaban Island, Batangas Province, Luzon, Philippines (13.672230°N, 120.841861°E), 19 m depth, collected 18.iii.2008 by GoogleMaps T. Gosliner et al . CASIZ 177608 , one specimen, subsampled for DNA, Bethlehem , Maricaban Island, Batangas Province, Luzon, Philippines (13.672230°N, 120.841861°E), 21 m depth, collected 17.iv.2008 by GoogleMaps T. Gosliner . CASIZ 177413 , one specimen, subsampled for DNA, Bethlehem , Maricaban Island, Batangas Province, Luzon, Philippines (13.672230°N, 120.841861°E), 21 m depth, collected 19.iii.2008 by GoogleMaps T. Gosliner et al . CASIZ 104726 , five specimens, 5–9 mm, two 9 mm specimens dissected, Tengan Pier , Ishikawa City, Okinawa, Ryukyu Islands, 13 m depth, collected 9.vii.1991 by R. Bolland . CASIZ 079259 , five specimens, two dissected, Tengan Pier , Ishikawa City, Okinawa, Ryukyu Islands, Japan, 13 m depth, collected 9.vii.1991 by R. Bolland .

Geographical distribution: This species is known only from Okinawa, the Philippines (present study), and Papua New Guinea ( Coleman, 2008).

Etymology: The specific name funiculus is from the Latin word for ‘thin rope or cord’ to describe the appearance of the longitudinal ridges of this species.

External morphology: The body shape of the living animal ( Fig. 42E–H View Figure 42 ) is elongate, flattened, and narrows at the posterior end. The dorsal ridges are nearly parallel along the midline, but angle towards the mantle margin along the sides of the notum. The foot does not project beyond the distinct mantle margin. There is a series of 12–23 longitudinal dorsal ridges. The oral veil extends forward and has blunt extensions at the corners. The wide-spaced rhinophores are behind the oral veil. They have a series of longitudinal lamellae on the rounded club. The stalk does not narrow noticeably. There are visible marginal sacs along the mantle edge. The genital opening is on the right side of the anterior quarter of the body. The anus is situated approximately one third of the way to the posterior end of the body. There are no branchial or hyponotal lamellae under the mantle margin. The ground colour of the dorsum and dorsal ridges is white to bluish or orange. The oral veil and the foot are opaque white with an orange frontal margin. The depressions between the dorsal ridges are light grey or orange with dark dots. There are dark bands of colour across the notum, beginning approximately halfway from the anterior end. Along the mantle edge are evenly spaced, dark spots of colour. The mantle has a pinkish-orange border. The rhinophore stalk is white and the club is dark brown with opaque white to cream lamellae and apex.

narrow and slightly convoluted and widens slightly as it enters the elongate, bulbous penial sac. Within the penial sac, the penis is elongate and wide distally terminating in a rounded apex. Adjacent to the penis is the thin, straight vagina, which terminates in a relatively large, pyriform bursa copulatrix. The vagina is about the same diameter throughout.

Buccal armature: The buccal armature was examined in five paratype specimens [ CASIZ 104726, 177377 (two specimens), 079259 (two specimens)]. The jaws are large and thickly cuticularized ( Figs 54A View Figure 54 , 55A View Figure 55 , 56A View Figure 56 ), with a thick masticatory margin and five to seven rows of long, pointed denticles ( Figs 54B View Figure 54 , 55B View Figure 55 , 56B View Figure 56 ). The radula is long and narrow ( Figs 54C View Figure 54 , 55C View Figure 55 , 56C View Figure 56 ) with a formula in four paratypes of +17 ¥ 6.1.1.1.6 ( CASIZ 079259), 33 ¥ 6.1.1.1.6 ( CASIZ 079259), 34 ¥ 6–8.1.1.1.6–8 ( CASIZ 104726), and 31 ¥ 6.1.1.1.6 ( CASIZ 177377). The rachidian teeth ( Figs 54D, E View Figure 54 , 55D–F View Figure 55 , 56D–F View Figure 56 ) have a broad base with a large, thick, and long central cusp that is wider than the six to nine flanking denticles on each side. The inner lateral tooth ( Figs 54D, E View Figure 54 , 55D–F View Figure 55 , 56D–F View Figure 56 ) has a wide base with a prominent cusp with 7–16 short, narrow, pointed denticles on the outside surface of the base. The next two lateral teeth are distinct, having a wide base, a long, projecting hook-shaped first denticle and up to 16 smaller, pointed denticles. The last four lateral teeth ( Figs 54F View Figure 54 , 55E, F View Figure 55 , 56D–F View Figure 56 ) are hook-shaped without denticles.

Reproductive system ( Fig. 57 View Figure 57 ): The reproductive organ arrangement is androdiaulic. The hermaphroditic duct leads into the wide ampulla. The ampulla is thick and simply curved. It bifurcates into the large female gland mass via a short oviduct and 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 relatively Remarks: Externally, D. funiculus looks most similar to two species from Japan, D. cymatilis (see the Remarks above for D. cymatilis ) and D. striatellus Baba, 1976 . Other Dermatobranchus species have the dark bands of colour across the notum, such as D. albus and D. otome Baba, 1992 , but D. albus can have tiny dark spots within the band of colour, and the dorsal ridges are white or orange, as are the depressions between the ridges. Dermatobranchus otome has ocellated spots on the dorsal ridges whereas D. funiculus does not. The dorsal ridges of D. striatellus are arranged in a reticulated pattern and there are no dark bands of colour perpendicular to the dorsal ridges as found in D. funiculus . There are tiny black dots of colour on the dorsum of D. funiculus and the rhinophore club is dark brown. This is in contrast to D. striatellus that has no dark dorsal dots and has orange red rhinophores.

Dermatobranchus funiculus ( Figs 54–56 View Figure 54 View Figure 55 View Figure 56 ) has some similarities in radular morphology to D. striatellus ( Baba, 1949: text fig. 86). For example, both species have a broad-based rachidian tooth with a projecting, spear-shaped median cusp. Both have a similarly shaped, denticulate first lateral tooth. However, in D. funiculus , the second and third lateral teeth are denticulate, unlike the simple hooks of D. striatellus . The radular formula of D. striatellus is 32 ¥ 11– 12.1.1.1.11– 12 in contrast to D. funiculus with a radular formula of 31–34 ¥ 4.2.1.1.1.2.4. Neither of the externally similar species D. otome nor D. albus have distinctive, denticulate second and third lateral teeth, whereas D. funiculus does.

Baba (1992) did not describe the reproductive system of D. otome . However, we examined specimens of D. otome ( Fig. 21 View Figure 21 ), and there are several differences. In D. otome the prostate is more convoluted than in D. funiculus ( Fig. 57 View Figure 57 ), and the bursa copulatrix duct of the former is more elongate and curved. Additionally, a comparison can be made between D. funiculus and D. albus ( Fig. 11 View Figure 11 ). Both species have similar features such as a wide ampulla, narrow vaginal duct, and a large, bulbous penial sheath. However, the hermaphroditic duct is comparatively longer in D. albus , the ampulla is much larger and more tubular than that of D. funiculus . In addition, the penial sheath in D. funiculus is much larger, proportional to the other reproductive organs than is the penial sheath in D. albus . Finally, the prostate of D. funiculus is longer and more coiled than that of D. albus .

Dermatobranchus funiculus should be compared to other species with a long narrow radula, namely D. fortunatus , D. substriatus , D. earlei , D. kokonas , D. piperoides , D. rodmani , and D. albineus . Dermatobranchus fortunatus , D. rodmani , D. kokonas , and D. piperoides all lack longitudinal ridges and have very different colour patterns from D. funiculus .

Of the species with longitudinal ridges all differ consistently from D. funiculus . The external coloration of D. substriatus remains unknown. However, it has fewer (nine) longitudinal and diagonal ridges than does D. funiculus (12). Internally, the radula of D. substriatus has few teeth per row (nine) versus 15 in D. funiculus . The reproductive anatomy of D. substriatus remains unknown. Further comparison of the two species must await the rediscovery of additional material from the type locality of D. substriatus (Sagami Bay region of Japan).

The colour of D. albineus is very different from that of D. funiculus . It has pink pigment between the white ridges as compared to the grey of D. funiculus . Internally, D. albineus has many more (13–17) outer lateral teeth per row than does D. funiculus (six).

Dermatobranchus earlei has a bluish body colour with brown pigment on the notum. The central cusp of the rachidian tooth of D. earlei is much broader than that of D. funiculus and there are more lateral teeth per half row of D. earlei (nine) than in D. funiculus (six). In the reproductive system of D. funiculus ( Fig. 57 View Figure 57 ) the prostate is more convoluted than in D. earlei ( Fig. 49 View Figure 49 ).