Paradoris undefined-a

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 : 204-208

PARADORIS SP. A ( FIGS 57A, B , 58–71 )

Material dissected: TANZANIA, Zanzibar, Matenwe , 7 November 1994, one specimen 16/ 11 mm preserved, leg. James McLean, identified as Discodoris by T. M. Gosliner ( CASIZ 165833 ) ; Tanzania, Zanzibar, Matenwe , 7 November 1994, two specimens 20/12 (#1) mm and 17/10 (#2) mm preserved, leg. James McLean, identified as Discodoris by T. M. Gosliner ( CASIZ 099299 ) ; SEYCHELLES, Aldabra Atoll , Passe Femme, 9°S, 46°E, 22 March 1986, two specimens 11/8 (#1) and 5/2 (#2) mm preserved, leg. T. M. Gosliner, identified as Dorididae by T. M. Gosliner ( CASIZ 075996 ) ; Seychelles, Aldabra Atoll , Lagoon between Passe Femme and Passe du Bois, 9°00′S, 46°00′E, 19 March 1986, two specimens 9/4 (#1) and 7/3 (#2) mm preserved, leg. T. M. Gosliner, identified as Discodoris by T. M. Gosliner ( CASIZ 074244 ) ; Seychelles, Aldabra Atoll , Lagoon between Passe Femme and Passe du Bois, 9°S, 46°E, 19 March 1986, one specimen 6/ 3 mm preserved, leg. T. M. Gosliner, identified as Discodoris by T. M. Gosliner ( CASIZ 074204 ) ; New Caledonia, Banc de Touho , 20°44.6′S, 165°13.7′E, 15–35 m depth, station 1259, September 1993, two specimens 20/12 (#1) and 23/12 (#2) mm preserved, leg. Expédition Montrouzier, identified as ‘ Doridien NC 196’ ( MNHN, no catalogue number) ; HAWAII, Puako , 17 June 1994, one specimen 7/ 4 mm preserved, leg. P. Fiene, identified as Discodoris by T. M. Gosliner ( CASIZ 101114 ) .

Distribution: Indo-West Pacific: Indian Ocean ( Zanzibar, Seychelles), New Caledonia, and Hawaii.

Abundance: So far, I could find a total of 11 specimens.

Habitat: On a wall ( MNHN), on a wall at night ( CASIZ 101114).

Morphological and anatomical description (including character variation): Colour pictures of live animals were available for two specimens ( CASIZ 099299 and CASIZ 165833): one animal was homogeneously dark brown and the other was brown matched with lighter areas ( Fig. 57A, B ). The gills and the rhinophores are lighter than the notum; the margins of the gills and the tips of the rhinophores are white. The colour of the ventral surface alive is unknown. All preserved specimens are currently colourless, homogeneously pinkish, whitish, or greyish, including the ventral surface. Specimens from New Caledonia ( MNHN) bear minute dark dots on the dorsal notum .

The body is oval ( Figs 57A, B , 58B, C ). The largest specimen is 23 mm long preserved, i.e. 30 mm alive ( MNHN #2). The foot is rounded posteriorly and anteriorly. The width of the foot equals approximately onethird or one-half the width of the dorsal notum (in preserved specimens); the foot of specimens from Zanzibar is almost as wide as the dorsal notum. The anterior margin of the foot is bilabiate and the upper lip is notched ( Fig. 58A, C ). The grooved oral tentacles are digitiform or conical ( Fig. 58A, C ). The dorsal notum of preserved specimens is smooth, except for the specimens from New Caledonia, which have three or four large bumps on the median line between the rhinophores and the gills ( Fig. 58B ). Numerous wide holes could easily be observed on the surface of the dorsal notum of all specimens ( Figs 58D–F , 59 ). Small holes (diameter <10 µm) and tufts of cilia are also present on the dorsal notum, including on gills and rhinophores ( Fig. 60 ). In preserved specimens, the margins of the rhinophoral and branchial sheaths are smooth. There are six multipinnate branchial plumes: the individual from the Seychelles ( CASIZ 074204), which has five plumes, probably lost one plume. The rhinophores have between nine ( CASIZ 075996 #2) and 15 ( CASIZ 165833) lamellae, mainly depending on the size of the animal (there are 12 lamellae in the largest specimen, MNHN #2).

The position of the stomach is intermediary between a narrow, median pouch and a free, large pouch ( Fig. 61A, B ). The shape and the position of the stomach vary among individuals. A caecum is present, on the left, posterior side of the stomach. The intestine is straight and dorsal. The labial cuticle is armed with two lateral plates, and an additional, ventral jaw plate ( Figs 62–64 ). The two lateral jaw plates are rectangular, longer than wide, and are entirely covered with rodlets. Also, the shape of the rodlets is very homogeneous: unlike in other species, the tip of all rodlets (except for the first row of rodlets on the anterior edge) is rhomb-shaped. As a result, the lateral plates seem to be entirely covered with a diamond paving. Rhombshaped tips are caused by the presence of an anterior spur (as in other Paradoris ) and a posterior spur; on lateral view, rodlet tips are T-shaped.

The radula is elongated ( Figs 65–68 ): its length equals at least three times its width. The radular sac can be seen by dorsal dissection. Radular formulae were: 35 × (10-0-10) in a 5 mm long specimen ( CASIZ 075996 #2); 35/40 × (11-0-11) in a 7 mm long specimen ( CASIZ 074244 #2); c. 35 × (17-0-17) in a 7 mm long specimen ( CASIZ 101114 ) ; 38 × (13-0-13) in a 9 mm long specimen ( CASIZ 074244 #1); 41 × (17-0-17) in a 11 mm long specimen ( CASIZ 075996 #1); 41 × (17-0- 17) in a 16 mm long specimen ( CASIZ 165833 ) ; 40/ 45 × (21-0-21) in a 20 mm long specimen ( MNHN #1 ) ; 45 × (16-0-16) in a 17 mm long specimen ( CASIZ 099299 #2); 45 × (25-0-25) in a 23 mm long specimen ( MNHN #2 ) ; 50 × (19-0-19) in a 20 mm long specimen ( CASIZ 099299 #1); note that the number of rows in the specimen from Hawaii ( CASIZ 101114 ) is uncertain because part of its radula was damaged during the preparation; also, the radula of one specimen from the Seychelles was lost ( CASIZ 074204 ) . 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. A strong dorsal spur is present on the hook of all the outermost teeth. Also, the base of the last outermost tooth may bear a spur, but not in all rows. All radulae are symmetrical: the number of teeth per row on the left side equals the number of teeth per row on the right side.

The cerebral and pleural ganglia are not fused with the pedal ganglia ( Fig. 61C, D ). The circumoesophageal nerve ring is short. The surface of the ganglia is smooth.

The reproductive system is located on the right side of the body, between the buccal mass and the digestive gland ( Figs 61A, B , 69–71 ). Two small specimens were immature and had no reproductive system (CASIZ 074204, CASIZ 075996 #2); two specimens were not fully mature and had a small female gland mass (CASIZ 074244). The white ampulla is convoluted, with one loose loop. The division between male and female ducts (hidden within the female gland mass) could not be seen by dissection. The flattened prostate is divided in a proximal, whitish part and a yellowish, distal part. The white deferent duct is not significantly convoluted. A distinct, conical, copulatory organ was found in all specimens. It certainly is a permanent penis ( Fig. 71 ). It is small: 0.24 mm (CASIZ 165833, CASIZ 075996 #1), 0.27 mm (MNHN #1), 0.3 mm (CASIZ 099299 #2), 0.36 mm (CASIZ 099299 #1). The vaginal duct is straight or loosely convoluted. The fertilization duct may be convoluted (with a few loops) near the bursa copulatrix. The duct of the receptaculum seminis is not significantly longer than usual. The disappearance of the fertilization duct into the female gland mass (where it connects to the fertilization chamber) is marked by a very short duct. Both spermatic pouches (bursa copulatrix and receptaculum seminis) are spherical-ovate and smooth; they can be close to each other or separate. Their relative sizes vary: the bursa copulatrix can be either as large as the receptaculum seminis or approximately five times larger. No accessory glands or stylet sacs could be found.

Diagnostic features: The two lateral jaw plates are longer than wide ( Figs 62A , 63A ), instead of sickleshaped and wider than long, and their surface is entirely covered with rodlets. Also, all rodlet tips are rhomb-shaped (except for the first anterior row of rodlets), and the two lateral plates are entirely covered by a diamond paving ( Figs 62F , 63 , 64 ).

Discussion: As far as I can discern, this species is new: sp. A has a distinguishing, diagnostic jaw anatomy. The only other species of Paradoris that always lacks accessory glands and stylet sacs is dubia . The latter, however, presents several diagnostic features that are absent in sp. A. Despite the fact that I evaluated the variation in several characters (especially the diagnostic features), I have not created a new name for sp. A. The main reason is that I do not have any alcohol-preserved specimens. I think that some types should be preserved in a way that allows future workers to use them in molecular studies, especially in phylogeography. I believe that it is important that these alcohol-preserved or frozen specimens be types in order to avoid any misidentification. Ideally, the alcohol-preserved type should be the name bearer. Also, one will have to address the variation in the colour of live animals, which is still poorly known.

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 58. Paradoris sp. A. A, anterior, ventral view, MNHN #1, scale = 4.5 mm. B, dorsal view, MNHN #1, scale = 7.5 mm. C, ventral view, CASIZ 099299 #1, scale = 7.5 mm. D, mantle holes, CASIZ 101114, scale = 0.5 mm. E, mantle holes, MNHN #1, scale = 1 mm. F, mantle holes, CASIZ 099299 #1, scale = 1 mm.

Figure 59. Paradoris sp. A, dorsal notum. A, CASIZ 075996 #2, scale = 100 µm. B, CASIZ 075996 #2, scale = 20 µm. C, MNHN #1, scale = 100 µm. D, MNHN #1, scale = 10 µm. E, CASIZ 099299 #1, scale = 100 µm. F, CASIZ 101114, scale = 100 µm.

Figure 60. Paradoris sp. A. A, rhinophoral lamellae, CASIZ 165833, scale = 20 µm. B, rhinophoral lamellae, CASIZ 099299 #1, scale = 20 µm. C, branchial plume (detail), CASIZ 099299 #1, scale = 100 µm. D, branchial plume (detail), CASIZ 165833, scale = 100 µm.

Figure 61. Paradoris sp. A, internal anatomy. A, general anatomy, MNHN #1, scale = 2.8 mm. B, anterior, general anatomy, CASIZ 099299 #1, scale = 3.1 mm. C, central nervous system, dorsal view, MNHN #1, scale = 1 mm. D, central nervous system, dorsal view, CASIZ 099299 #1, scale = 1 mm.

Figure 62. Paradoris sp. A, jaws and jaw rodlets. A, two lateral jaws, MNHN #1, scale = 100 µm. B, median, ventral jaw plate, MNHN #1, scale = 100 µm. C, lateral jaw rodlets, MNHN #1, scale = 10 µm. D, median jaw rodlets, MNHN #1, scale = 2 µm. E, median jaw rodlets, MNHN #2, scale = 20 µm. F, lateral jaw rodlets, MNHN #2, scale = 10 µm.

Figure 63. Paradoris sp. A, lateral jaw rodlets. A, CASIZ 075996 #1, scale = 100 µm. B, CASIZ 075996 #1, scale = 20 µm. C, CASIZ 075996 #2, scale = 10 µm. D, CASIZ 074204, scale = 10 µm. E, CASIZ 074244 #1, scale = 2 µm. F, CASIZ 074244 #1, scale = 10 µm. G, CASIZ 074244 #2, scale = 10 µm.

Figure 64. Paradoris sp. A, lateral jaw rodlets. A, CASIZ 099299 #2, scale = 10 µm. B, CASIZ 099299 #2, scale = 3 µm. C, CASIZ 099299 #1, scale = 10 µm. D, CASIZ 101114, scale = 20 µm. E, CASIZ 165833, scale = 10 µm. F, CASIZ 165833, scale = 10 µm.

Figure 65. Paradoris sp. A, radular teeth. A, left rows, CASIZ 074244 #1, scale = 20 µm. B, right rows, CASIZ 074244 #1, scale = 20 µm. C, left, outermost teeth, CASIZ 074244 #1, scale = 10 µm. D, right, outermost teeth, CASIZ 074244 #2, scale = 3 µm. E, left rows, CASIZ 074244 #2, scale = 10 µm. F, right rows, CASIZ 074244 #2, scale = 10 µm.

Figure 66. Paradoris sp. A, radular teeth. A, left, outermost teeth, CASIZ 075996 #1, scale = 20 µm. B, right, outermost teeth, CASIZ 075996 #2, scale = 10 µm. C, an outermost lateral tooth, lateral view, CASIZ 075996 #2, scale = 10 µm. D, innermost lateral teeth, CASIZ 101114, scale = 10 µm. E, right rows, CASIZ 101114, scale = 20 µm. F, right, outermost teeth, CASIZ 101114, scale = 10 µm.

Figure 67. Paradoris sp. A, radular teeth. A, radula, CASIZ 099299 #1, scale = 200 µm. B, right rows, CASIZ 099299 #1, scale = 30 µm. C, innermost teeth, CASIZ 099299 #1, scale = 10 µm. D, rows, CASIZ 099299 #2, scale = 30 µm. E, left rows, CASIZ 099299 #2, scale = 30 µm. F, right rows, CASIZ 099299 #2, scale = 20 µm.

Figure 68. Paradoris sp. A, radular teeth. A, left rows, MNHN #2, scale = 30 µm. B, right rows, MNHN #2, scale = 100 µm. C, innermost teeth, MNHN #2, scale = 20 µm. D, rows, CASIZ 165833, scale = 30 µm. E, left, outermost lateral tooth, CASIZ 165833, scale = 10 µm. F, right, outermost teeth, CASIZ 165833, scale = 20 µm.

Figure 69. Paradoris sp. A, reproductive system. A, general view, CASIZ 074244 #1, scale = 0.6 mm. B, general view, CASIZ 074244 #2, scale = 0.4 mm. C, general view, CASIZ 074244 #1, scale = 0.6 mm. D, general view, CASIZ 074244 #2, scale = 0.4 mm.

Figure 70. Paradoris sp. A, reproductive system. A, general view (rs moved), CASIZ 099299 #1, scale = 2 mm. B, general view, CASIZ 099299 #2, scale = 1.5 mm. C, general view (rs moved), CASIZ 165833, scale = 1.3 mm. D, general view (rs moved), MNHN #1, scale = 1.5 mm. E, general view, CASIZ 101114, scale = 0.5 mm.

Figure 71. Paradoris sp. A, penis. A, CASIZ 099299 #1, scale = 30 µm. B, CASIZ 165833, scale = 100 µm. C, MNHN #1, scale = 20 µm. D, CASIZ 099299 #2, scale = 20 µm. E, CASIZ 075996 #1, scale = 20 µm.