Floscularia curvicornis, Rougier & Pourriot, 2006

Rougier, Claude & Pourriot, Roger, 2006, On some rare and new species of rotifers (Digononta, Bdelloida; Monogononta, Ploima and Flosculariaceae) in the Kaw River estuary (French Guiana), Zoosystema 28 (1), pp. 5-16 : 10-12

Floscularia curvicornis n. sp.

(Fig. 4)

TYPE LOCALITY. — Kaw River estuary ( French Guiana), mangrove swamp station (M).

TYPE MATERIAL. — Holotype mounted on slide ( MNHN AM 868 ); paratype mounted on slide ( MNHN AM 869 ).

OTHER MATERIAL EXAMINED. — Same locality, 1 specimen photographed.

DIAGNOSIS. — The species is characterised by two long and curled ventral tentacles, a morphological character not seen in other species to date.

MEASUREMENTS (in µm). — Trunk length 185-300, trunk width 80, foot length up to 600, ventral tentacles length 50-60.

OCCURRENCE. — Mangrove swamp station (M, Fig. 1) during spring tide (outflow).

DESCRIPTION

The divided corona (four lobes) and the presence of two small neck hooks are evidence that it belongs to the genus Floscularia Cuvier, 1798 (see Segers 1997).

A sheath, usually present in all members of the genus ( Koste 1972; Segers 1997; Fontaneto et al. 2003) was not seen. The foot is very long (400- 600 µm), more than twice the length of the trunk. On the contracted individual, a small dorsal antenna is situated at the base of the hooks. A specific character is the presence of two long, lumbar and curled antennas, widely separated at their base (= ventral tentacles “apically” displaced). There is no apical cuticular wing-like structure as in F. noodti ( Koste, 1972) .

Unci formula: three big teeth followed by approximately six thinner teeth.

Family TESTUDINELLIDAE Bartos, 1959 Genus Testudinella Bory de Saint-Vincent, 1826

Testudinella haueriensis Gillard, 1967 (Fig. 5)

TYPE MATERIAL. — Because of the loss of type specimens (no trace of holotype in Belgium after extensive searching by Segers) and with the original descriptions limited to morphology, a neotype is here designated: ♀ from French Guiana, mounted on slide ( AM 872).

OTHER MATERIAL EXAMINED. — 6 specimens preserved in an Eppendorf tube ( AM 873).

DIAGNOSIS. — The large Guianan specimens of T. haueriensis are characterised both by a strong spine at the middle of the anterior aperture and by ramified gastric glands and, to a lesser degree, vitellogen.

MEASUREMENTS OF GUIANAN SPECIMENS (in µm). — Total body length 280-335 (anterior spine included), body width 215-235, frontal spine length 31-44.

OCCURRENCE. — Estuary station (E, Fig. 1) during the spring tide (outflow), and sporadically in a sample from the mangrove swamp (M, Fig. 1) (neap tide, inflow) and at the mud flat station (V, Fig. 1) (neap tide and spring tide).

DISCUSSION

Testudinella haueriensis was described in terms of morphological criteria by Gillard from the Maica Lake within the Amazon watershed. A similar species (or the same?), but larger, was observed by Koste (1972) and Koste et al. (1983) at the same location and was considered to be a subspecies named T. mucronata haueriensis ( Gillard, 1967) . Unfortunately, none of these reports gives any indication about their anatomy. Nevertheless, referring to the catalogue of the Academy of Natural Sciences of Philadelphia (ANSP) Rotifer Collection, established by Jersabek et al. (2003), the specimen collected in Florida and mounted by Myers under the No. ANSP 36 possesses very ramified gastric glands and vitellogen.

A similar giant (350 µm) form from the Ivory Coast, but lacking a frontal spine, was described as T. dendradena by De Beauchamp (1955). This author, however, discovered after the publication of his note that this Testudinella had already been described and figured by C. F. Rousselet (in an addition to the note of Kirkman [1901], on rotifers from Natal) under the name T. ( Pterodina ) “ trilobata ”, which was inappropriate according to Harring (1915). In his revision of 1978, Koste considers these last two forms as subspecies of T. patina , even though the anatomy of T. patina differs (De Beauchamp 1955). Finally, a succinct description of a form similar to the previous species was made by Daday (in De Beauchamp 1955) from rotifers of Paraguay, under the name T. (Pterodina) mucronata Gosse, 1886 . All these reports are confusing in the systematics of Testudinella , especially between the patina and mucronata groups. Nevertheless, De Smet (2005) observes notable differences in the morphology of the trophi (SEM) between T. haueriensis and T. mucronata that also justifies the distinction of the two species.

Reviewing the Testudinella literature, we can make the following observations: based on its size (<150 µm) and anatomy, T. mucronata can be linked to the patina group (as done by Koste 1978); further, the two species T. mucronata and T. patina have been observed cohabiting ( Hudson & Gosse 1886), and they are both cosmopolitan and common in temperate freshwaters. They differ by the presence/ absence of a medio-anterior frontal spine.

The group of tropical forms, all of large size (> 250 µm), seem to be heterogeneous (as shown in Table 2). The so-called T. “ trilobata ” of Rousselet ( Kirkman 1901) and T. dendradena De Beauchamp, 1955 show the same peculiar anatomy, with ramified gastric glands and vitellogen, and with no anterior spine. On the other hand, T. haueriensis ( Gillard 1967) and the giant form described by Koste (1972) possess a dorsal mucron, but the structure of the gastric glands and vitellogen are unknown. Harring (1915) described, from the Black Swamp in Panama, a ramified vitellogen form with a long and slender spine on the dorsal margin of the anterior median lobe, and noted the presence of the same in Guatemala (Juday collection) and Paraguay ( Daday 1905). The French Guianan specimens accord perfectly with the description of Harring. The distribution of all of these ramified vitellogen and gastric gland forms seems to be exclusively tropical.

Therefore, the problem is to decide whether the larger size, presence of a medio-antero-dorsal mucron, and morphology of the gastric glands and vitellogen are valuable specific criteria. As anatomic characters can be considered for other families ( Pourriot 1989), why not here? It thus appears to be necessary to examine both morphology and anatomy to identify the genus Testudinella .

Family SYNCHAETIDAE Remane, 1933