Limnias novemceras, Meksuwan, Phuripong, Jaturapruek, Rapeepan & Maiphae, Supiyanit, 2018

Meksuwan, Phuripong, Jaturapruek, Rapeepan & Maiphae, Supiyanit, 2018, Two new species of genus Limnias from Thailand, with keys to congeners (Rotifera, Gnesiotrocha), ZooKeys 787, pp. 1-15 : 5-9

Limnias novemceras sp. n.

Material examined.

Holotype. A contracted female in a mounted slide was deposited in Princess Maha Chakri Sirindhorn Natural History Museum (PSUNHM), Prince of Songkla University, Songkhla, Thailand: PSUZC-PK5PM3-1. Paratypes. Two females in PSUNHM: PSUZC-PK5PM3-2-3; four females in Zoology Laboratory, Science Program, Faculty of Science and Technology, Phuket Rajabhat University, Phuket, Thailand: PKRU-RF1-1-4. In total, nine specimens were examined.

Type locality.

A stream in Krabi Province, Thailand: 8°12.687'N, 98°46.899'E. Individuals of L. novemceras , sp. n. were found on leaves of Hydrilla verticillata (L.f.) Royle growing in littoral area of the stream. June 2nd, 2011.

Etymology.

The species name is a substantive, and refers to the number of projections (nine, fromthe Latin novem, and horn, from the Greek ceras) on the dorsal plate.

Diagnosis.

Limnias novemceras sp. n. is easily recognized by its dorsal corona gap being much wider than the tube diameter, by its long ventral antennae that reach beyond the fully extended corona, and by its dorsal plate carrying nine projections. In addition, this species never raises its corona far beyond the tube opening (Figs 1 D–F, 4 A–C, 7B).

Description.

Tube ringed, transparent, proximal part smooth, transparent. Trunk slender, tapers into slender foot with short stalk (Figs 1D, 4A). Corona two-lobed, more than twice as wide as trunk, ventral sinus depth between one third and one half of corona height, dorsal gap nearly 1.5 times as wide as trunk width (Figs 1D, 4B). Two long ventral antennae extending beyond the extended corona. Dorsal plate stiff, with nine projections, upper row a pair of short and broad projections, middle row with a central, distally bifid projection, two lateral rounded projections and, slightly more distally, two low and broad, ridges, lower row a pair of oblique, rounded, low projections, these rounded triangular with straight inner margin in SEM preparation. Dorsal antenna aperture situated at one fifth of the dorsal plate length from the anterior margin (Figure 7B). Trophi malleoramate, symmetrical. Left and right proximal unci teeth: 3/3, distal teeth: 16 –17/16– 17 (Figure 8B). Rami apophyses equal. Manubria crescent-shaped with three chambers. Corona width: 114-126, corona height: 41 -47, depth of ventral sinus: 11-16, width of dorsal gap: 74-80, length of lateral antennae: 43-44 (in µm).

Distribution.

The species is known only from its type locality.