Pentatrocha, Segers & Shiel, 2008

Segers, Hendrik & Shiel, Russell J., 2008, Diversity of cryptic Metazoa in Australian freshwaters: a new genus and two new species of sessile rotifer (Rotifera, Monogononta, Gnesiotrocha, Flosculariidae), Zootaxa 1750 (1), pp. 19-31 : 22-23

Pentatrocha new genus

Description. Adult females large, sessile, with bulky foot and trunk. Corona large, tilted to dorsally, with distinct cingulum and trochus; antero-medially concave around buccal area. Corona with two pairs of antero-lateral lobes and a single middorsal lobe, all lobes separated by shallow sinuses. A dorsal ovifer present posterior to the cloacal aperture. Gelatinous case amorphous, weakly developed, without exogenous elements. Trophi malleoramate. The single species in this genus is the largest extant rotifer.

Differential diagnosis. The new genus is characterised by its unique corona morphology, in combination with the presence of an ovifer. The latter feature is shared with Sinantherina Bory de St. Vincent , which has a heart-shaped corona without distinct lobes. Of other Flosculariidae , only Octotrocha Thorpe and Floscularia Ehrenberg have a lobed corona. Both Octotrocha and Floscularia have a corona provided with a large, inverse V- or U-shaped dorsal concave sinus that lacks cilia; a dorsal interruption of the corona is absent or, at best, not discernible in Pentatrocha new genus.

Type species. Pentatrocha gigantea new species (Monotype)

Etymology. The name of the genus refers to the autapomorphic feature of the genus, the five-lobed corona (G., penta, five + G., trocha, wheel)