Trapania tamaraw, Smirnoff & Donohoo & Gosliner, 2022

Smirnoff, Dimitri S., Donohoo, Samantha A. & Gosliner, Terrence M., 2022, Extra-branchial processes manifest extra diversity: systematics of the genus Trapania (Nudibranchia: Goniodorididae) and nine new species descriptions, Zoological Journal of the Linnean Society 196, pp. 270-313 : 296-297

TRAPANIA TAMARAW SP. NOV.

( FIGS 12A , 4I , 13 )

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: F4449CAF-D81F-41CF-8FA2-FD8BE7F3710C.

Trapania sp. 13 Gosliner et al., 2018: 62, middle-right photograph.

Type material: Holotype: NMP 041334 , originally CASIZ 208391 , one specimen, dissected and sequenced, Puerto Galera (13.51350°N 120.95833°E), Mindoro, Mindoro Oriental Province, Philippines, 15–20 m depth, 28 March 2015, collected by P. J. Aristorenas.

Type locality: Puerto Galera (13.51350°N 120.95833°E), Mindoro , Mindoro Oriental Province, the Philippines .

Geographical distribution: Known only from Puerto Galera, the Philippines.

Etymology: A tamaraw is the native name for the dwarfed hoofed buffalo endemic to Mindoro, Bubalus mindorensis (Heude, 1888) . The horns of this buffalo resemble the well-developed and large jaws of this species compared to other members of the genus Trapania .

External morphology: Live animal 4 mm ( Fig. 12A ). Live animal coloured with alternating blotches of dark brown/ black and yellowish tan across the entire body.Rhinophores are cylindrical halfway up and conical to a blunt tip the rest of the way with five to six lamellae. Top two-thirds of the rhinophores have a purple-brown appearance, while the bottom third has light coloration, similar to other parts of the body. Gill plume consists of three branches that have a translucent yellow-tan appearance with the same coloration as the rhinophores along the gill plume tips. Extra-branchial and extra-rhinophoral appendages are elongated and curved, typical of Trapania . Each is coloured yellowish tan with a single spot of purple/brown coloration halfway along their length. Digitiform oral tentacles are dark brown/black at their base and yellowish tan at their distal halves. The anterior margins of the foot extend laterally as elongate appendages are dark brown/black at their base and translucent yellowish at their distal halves.

Buccal mass: The buccal mass is muscular with a moderately developed buccal pump on the dorsal surface. Inside the anterior portion of the mass is a pair of extremely well-developed jaws.The jaws ( Fig. 13A ) contain a single row of massive, acutely pointed, slightly curved, triangular jaw elements, equally spaced with regularly sized gaps ( Fig. 13B ). The radular formula of the holotype is 20 × 1.0.1 ( Fig. 13C ). The older teeth are much smaller than the newer ones ( Fig. 13D ) and the radula widens towards the more newly developed teeth. The teeth bear numerous denticles with the smallest ones being found on the inner edge of the tooth. There are approximately six to eight denticles on the inner side of the much larger, narrow primary cusp, and either no denticle on the outer side of the cusp or a series of up to eight minute, almost vestigial, short denticles on a few teeth. The denticles on the inner side of the primary cusp are generally larger nearer the primary cusp, but are not evenly graded.

Reproductive system: The mature reproductive system is triaulic ( Fig. 4I ). The saccate ampulla is narrow at the distal end where it connects to the ovotestis. From there, it abruptly widens before leading to a point where it divides into the short oviduct and vas deferens. The short, oviduct enters the female gland mass. The vas deferens gradually widens into a curved, thick prostatic portion and gradually transitions into the narrow, muscular ejaculatory portion that is continuous with the narrow, moderately short penial sac. The penial sac terminates at the gonopore adjacent to the vagina. The narrow vagina maintains its width from its opening through a long region prior to its junction with the large, ovoid bursa copulatrix and short narrow receptaculum duct. The receptaculum duct joins the smaller spherical receptaculum seminis near the long division of the short uterine duct, which enters the female gland mass. The female gland mass is composed of the large mucous gland and the smaller albumen and membrane glands.

Remarks: This species is compared to the four other members of its species complex below in the remarks following Trapania kamagong .

Figures

Figure 4. Reproductive systems. A, Trapania japonica (Baba, 1935), CASIZ 221116, scale = 0.50 mm. B, Trapania tatsulok sp. nov., holotype, NMP 041333 (formerly CASIZ 200530), scale = 0.33 mm. C, Trapania kahel sp. nov., holotype, NMP 041330 (formerly CASIZ 186131), scale = 0.28 mm. D, Trapania lemanioides sp. nov., holotype, NMP 041335 (formerly

Figure 13. Trapania tamaraw sp. nov. Scanning electron micrographs of buccal armature of holotype NMP 041334, (formerly CASIZ 208391). A, jaws. B, detail of rodlets. C, largest portion of radular ribbon. D, newly formed radular teeth.

Figure12. Living animals.A, Trapaniatamaraw sp.nov.,holotype,NMP 041334(formerly CASIZ 208391)PuertoGalera,Mindoro Oriental. B, Trapania stegodon sp. nov., holotype NMP 041332 (formerly CASIZ 186206), Anilao Harbor, Batangas, Philippines. C, Trapania sp. ‘Anilao’, preserved specimen, NMP 041329 (formerly CASIZ 182904), Anilao Harbor, Batangas, Philippines. D, Trapania kamagong sp. nov., holotype, NMP 041336 (formerly CASIZ 208585A), Puerto Galera, Mindoro Oriental, Philippines. E, upper photo Trapania kanaloa sp. nov., holotype CASIZ 189444, lower photo, Trapania sp. cf. kanaloa, CASIZ 199250, Koloa Landing, Kaua’i, Hawai’i, photo by Cory Pittman. F, Trapania undulata sp. nov., holotype, NMP 041331 (formerly CASIZ 186132), Ligpo Island, Bauan, Batangas, Philippines.