Paradoris undefined-c

Dayrat, Benoît, 2006, A taxonomic revision of Paradoris sea slugs (Mollusca, Gastropoda, Nudibranchia, Doridina), Zoological Journal of the Linnean Society 147 (2), pp. 125-238 : 216-220

PARADORIS SP. C ( FIGS 57F , 78 , 79 )

Material dissected: INDONESIA, Lembeh Strait , April 2003, one specimen 7/ 3 mm preserved, leg. C. Petrinos and D. W. Berhens, identified as Discodoris by T. M. Gosliner ( CASIZ 167456 ) .

Material examined (not dissected): PHILIPPINES, Luzon, Batangas Province, Maricaban Island, Sepok , Philippines , 18 April 1997, one specimen 5/ 2 mm

preserved, leg. Clay Carlson, identified as Discodoris by T. M. Gosliner ( CASIZ 110387).

Distribution: Indonesia and Philippines.

Morphological and anatomical description (including character variation): A colour picture was available for one live animal ( CASIZ 110387). The yellowish ground colour of the dorsal notum bears several black stripes ( Figs 57F , 78A ): three pairs of transversal stripes between the rhinophores and the gills (with an additional pair of vestigial stripes between the second and third pairs); a pair of longitudinal stripes on both sides of the gill pocket; a single, longitudinal stripe between the two rhinophores. The rhinophores and the tips of the gills are black. The ventral surface of the preserved specimen is currently whitish: its natural colour is unknown. The preserved specimen, after 7 years in alcohol, is almost homogeneously whitish: the stripes are still recognizable but largely faded. The preserved colour ( Fig. 78D ) of the other specimen ( CASIZ 167456), which remained in alcohol for only 1 year, is probably close to the colour of the live animal and is similar to the colour of the first specimen ( CASIZ 110387).

The body is elongated ( Figs 57F , 78A, D ). The longest specimen is 7 mm long, preserved, i.e. approximately 10 mm alive ( CASIZ 167456). The foot is rounded posteriorly and anteriorly. The width of the foot equals approximately one-third or one-half of the width of the dorsal notum (in preserved specimens). The anterior margin of the foot is bilabiate and the upper lip is notched ( Fig. 78C ). The grooved oral tentacles are digitiform ( CASIZ 110387). The oral tentacles of the other specimen could not be observed ( CASIZ 167456). The preserved, dorsal notum is globally smooth. Numerous wide holes could be observed on the surface of the dorsal notum ( Fig. 79A, B ). Small holes (diameter <10 µm) and tufts of cilia are also present on the dorsal notum. In preserved specimens, the margins of the rhinophoral and branchial sheaths are smooth. There are six tripinnate branchial plumes ( CASIZ 110387); the number of plumes could not be determined with certainty in the other specimen ( CASIZ 167456). The rhinophores have eight ( CASIZ 110387) and less than ten ( CASIZ 167456) lamellae.

The position of the stomach, poorly fixed, could not be determined. The intestine is straight and dorsal. The labial cuticle is armed with a pair of lateral jaw plates, and an additional, ventral jaw plate ( Fig. 79C ). Rodlet tips are irregular, pointed or rounded, and have a curved tip. The radula is elongated ( Fig. 79D–F ): its length equals at least three times its width. The radular sac can be seen by dorsal dissection. The radular formula was c. 40 × (12-0-13) in a 7 mm long specimen. The rachidian teeth are absent and the rachidian space is narrow. The rows of lateral teeth are at an angle of 45 degrees with the rachidian axis. All teeth are hamate and have no denticles. The hook of all lateral teeth is grooved on its outer edge. The size of the lateral teeth gradually increases towards the margins, except for the last two or three outermost ones, which are smaller. The hook of the outermost teeth does not present a dorsal spur. The radula is not asymmetrical: some right half-rows have 13 teeth, instead of 12; the left and right lateral teeth are all identical.

The nervous system was very poorly fixed and I could not observe its anatomy.

The reproductive system is located on the right side of the body, between the buccal mass and the digestive gland. However, the reproductive system of this specimen was immature and poorly fixed: only a few, tentatively identified organs could be observed ( Fig. 78B, E ). The ampulla does not seem to be convoluted. No distinct female gland mass could be found. The prostate seems to be flattened. The white deferent duct does not seem to be distinctly convoluted. No distinct penis or papilla was found at the distal end of the deferent duct. The receptaculum seminis could not be found. The bursa copulatrix is spherical-ovate. In the distal part of the reproductive system, one accessory gland and one stylet sac were observed.

Diagnostic feature: Black stripes on the dorsal notum ( Figs 57F , 78A, D ).

Discussion: Several issues will have to be addressed to discuss the taxonomic status of sp. C. First, adult individuals will have to be described. The specimen that I dissected was not sexually mature. Also, individual variation in several critical characters, such as colour and radular anatomy, will have to be evaluated. Actually, the two specimens referred to as ‘sp. C’ could be part of the same taxon as the specimens referred to as ‘sp. B’: the arrangement of the black stripes of sp. C could be a geographical variant of the arrangement found in sp. B; and one cannot exclude a possible infraspecific variation for radular symmetry and asymmetry (see erythraeensis ).

Figures

Figure 57. Live animals. A, sp. A, CASIZ 099299 (#1 or #2) or CASIZ 165833, total length (preserved) = 20 (#1), 17 (#2), or 16 (165833) mm. B, same as (A). C, sp. B, CASIZ 089053, total length (preserved) = 6 mm. D, sp. B, CASIZ 105261, total length (alive) = 12 mm. E, sp. B, CASIZ 099080, total length (alive) = 12 mm. F, sp. C, CASIZ 110387, total length (preserved) = 5 mm. Colour pictures by T.M. Gosliner (A, B), R. Bolland (C–E), and C. Carlson (F).

Figure 78. Paradoris sp. C. A, dorsal view, CASIZ 110387, scale = 1.7 mm. B, distal part of the reproductive system, with an accessory gland and a stylet sac, CASIZ 167456, scale = 0.4 mm. C, anterior, ventral view, CASIZ 167456, scale = 1 mm. D, dorsal view, CASIZ 167456, scale = 2.8 mm. E, genital organs, tentatively identified, CASIZ 167456, scale = 0.4 mm.

Figure 79. Paradoris sp. C, CASIZ 167456. A, dorsal notum, scale = 100 µm. B, dorsal notum, scale = 100 µm. C, jaw rodlets, scale = 3 µm. D, radular rows, scale = 10 µm. E, left, outermost teeth, scale = 3 µm. F, right, outermost teeth, scale = 10 µm.