Phyrella? ambigua ( Cherbonnier, 1988 ), 1954

Michonneau, François & Paulay, Gustav, 2014, Revision of the genus Phyrella (Holothuroidea: Dendrochirotida) with the description of a new species from Guam, Zootaxa 3760 (2), pp. 101-140 : 129-130

Phyrella? ambigua ( Cherbonnier, 1988)

Fig. 23

Lipotrapeza ambigua Cherbonnier, 1988: 236–237 , fig. 104 A–H; Type series: MNHN EchHh 2767; type locality: Madagascar, Tuléar

= Phyllophorus (Phyllophorella) contractura Cherbonnier, 1988: 226–228 , fig. A–L; Holotype: MNHN EcHh 3601; type locality: Madagascar, Tuléar

= Thyonidiella oceana Heding & Panning, 1954: 172–173 (in part)

Thyonidiella oceana: Cherbonnier, 1988: 229–232 , fig. 101 A–G

= Thyonidiella cherbonnieri Rowe & Richmond, 2004: 3306–3307

Material examined. Madagascar, Tuléar (all) : MNHN EcHh 2767, (syntypes of Lipotrapeza ambigua ) . MNHN EcHh 3601 (Holotype of Phyllophorus contractura ) . MNHN EcHh 2918 (Paratype of Phyllophorus contractura ), September 12 th 1972, coll. Thomassin, 1 specimen . MNHN EcHh 2969, August 17 th, 1969, coll. Thomassin. Paralectotypes : MNHN EcHh 3863, June 10 th, 1972, coll. Thomassin, 9 specimens . MNHN EcHh 2223, 1972, coll. Galénon, 7 specimens . MNHN EcHh 2913, May 16 th, 1972, coll. Thomassin, 8 specimens . MNHN EcHh 2921, June 11 th, 1972, coll. Thomassin, 1 specimen . MNHN EcHh 3794, 1975, coll. Galénon, 4 specimens . MNHN EcHh 2905, June 12 th, 1972, 1 specimen . MNHN EcHh 2920, May 29 th, 1972, coll. Thomassin, 1 specimen.

Description based on type series of P. ambigua . Two specimens partially dried up. One specimen is intact with introvert retracted; the other is dissected, with pharyngeal complex removed and in the jar. Body wall stiff, leathery, brown, covered with tube feet without any particular arrangement. Specimens about 1 cm long and 5 mm wide, light brown with relatively large, tubular podia covering the entire body wall; anal teeth present. Cherbonnier indicates that this species has 20 tentacles in 3 circles. The examination of the tentacles associated with the calcareous ring found in the jar reveals at least 16 tentacles (exact number difficult to assess given the state of preservation) in 2 circles. Cherbonnier indicates that radials and inter-radials are not fragmented, however his drawing (Fig. 104, H), which matches closely the calcareous ring found in the jar, shows that they are. Internal anatomy shows absence of intestine, respiratory trees shorter than in other Phyrella , gonads in two tufts formed by long, thin tubes, madreporite and stone canal apparently missing (Cherbonnier indicates that the stone canal is long and thin ending in a spherical madreporite), one globular Polian attached to the pharyngeal complex. Mid-dorsal body wall devoid of ossicles; podia with end plates and perforated plates. Cloacal region body wall with rosettes (Fig. 104, D in Cherbonnier, 1988) and irregular tables (Fig. 104, A, B in Cherbonnier, 1988), podia have end plates and perforated plates (Fig. 104, E in Cherbonnier, 1988).

Remarks. We consider Lipotrapeza ambigua Cherbonnier, 1988 , Phyllophorus contractura Cherbonnier, 1988 , and Thyonidiella cherbonnieri Rowe & Richmond, 2004 to all represent the same species. As first revisers, we select ambigua as the valid name for this species, appropriate given the confusion surrounding this assemblage and the poor state of preservation of the specimens. It is notable that the type series of all three species were collected at the same locality.

In the description of Lipotrapeza ambigua, Cherbonnier noted that the lot 2767 includes 12 specimens (holotype and paratypes). However, this lot only includes 2 specimens, and the holotype was not identified within the lot.

Synonymy and description of Phyllophorus (Phyllophorella) contractura . The holotype (MNHN Hol 3601) is in poor condition. As indicated by Cherbonnier, it is about 9 mm long, 4 mm wide, light brown with relatively large, tubular podia covering the entire body. The body wall shows evidence of decomposition. All internal organs and the cloacal region are missing. The small calcareous ring has been opened, and some of its elements are not in their natural position, however one of the inter-radials is clearly fragmented and does not match Cherbonnier's drawing (Fig. 99, I). Furthermore, the body wall does not contain ossicles, and the podia have end plates and perforated plates. The general appearance of the holotype, in conjunction with the fragmented inter-radials, the ossicle assemblage, the presence of anal teeth (as reported by Cherbonnier), and the collection locality indicate that this specimen is indistinguishable from Lipotrapeza ambigua . Examination of the paratype indicates that it was used for illustrations, and is a different species, assignable to Phyllophorus sensu lato.

Synonymy and description of Thyonidiella cherbonnieri . This species was erected as a new name for Malagasy specimens incorrectly attributed to Thyonidiella oceana by Cherbonnier (1988) (see Remarks under Phyrella above). As noted by Rowe & Richmond (2004) this species resembles T. oceana except for the lack of tables and presence of plates in the body wall. Most of the specimens identified by Cherbonnier as T. oceana are fairly similar. Body wall soft, fairly thin and covered with tube feet ( Fig. 23 , MNHN EcHh 2969). Color light to dark brown in preservative; some specimens darker at the extremities. Small (11–21 mm long, 5–8 mm wide), mostly cylindrical, with tapering posterior end and blunt anterior end when the introvert is retracted. Introvert retracted in all specimens examined, 1–2 mm long, light gray to almost black. Tube feet relatively long (~ 1 mm), of the same color as the rest of the body, abundant, covering both radial and inter-radial area without particular arrangement. Fifteen small, dark brown tentacles (number of tentacles on each circle difficult to discern). Cloaca dark brown, surrounded by 5 small anal teeth. Polian vesicle single, light brown, with sparse small dark spots, about 1 mm long. Stone canal lightly-calcified, embedded in membrane surrounding calcareous ring; madreporite single, small (<1 mm in diameter), spherical, partially embedded in membrane surrounding calcareous ring. When present, gonads in two tufts, composed of single, unbranched, 2–4 mm tubes. Digestive tract relatively short, most specimens eviscerated. Mid-dorsal body wall without ossicles. Podia with end plate and perforated plates. Cloacal region body wall with rosettes and tables in some specimens (not reported by Cherbonnier), podia with end plate and perforated plates. Cherbonnier notes he examined 25 specimens collected by Galénon, Thomassin in Tuléar Madagascar in 1975. MNHN holds 32 specimens in 8 lots of this species, all collected by Galénon or Thomassin in Tuléar Madagascar, between 1969 and 1975; four specimens date from 1975. We consider these discrepancies to be likely lapsus calami, and consider all material listed above to correspond to the syntype series designated by Rowe & Richmond (2004).

All specimens examined here are substantially smaller than other Phyrella species. This species fits Phyrella except for the absence of tables in the body wall, that it is smaller, and the presence of “bâtonnets des podia” (which we did not observe in our preparations). The shape of the body; the propensity to eviscerate; the size, shape and distribution of tube feet on the body; the shape of the perforated plates; the fragmentation of the calcareous ring and the presence of posterior prolongations; the presence of anal teeth; the presence of rosettes in cloaca and introvert make this species closer to Phyrella than to any other phyllophorid genus with fragmented inter-radials.

Ecology & distribution. Known from Madagascar, with specimens from Mauritius & Rodriquez, Mascarene Islands (not seen by us) also attributed to this species by Rowe & Richmond (2004). Malagasy specimens were collected at low tide level under rocks set in sand on the Tuléar barrier reef. In Rodriquez, the species was found in a fore reef habitat under coral rock in 13–15m, as well as in a coastal bay. The Mauritius specimens were collected at Cannoniers Point.

Figures

FIGURE 23. A: One of the syntypes of Phyrella? ambigua, MNHN EcHh 2767 (dissected specimen); B: one of the syntypes of Thyonidiella cherbonnieri MNHN EcHh 2969. Scale bar, 1 cm.