Lecane phapi, Dang, Mau Trinh, Segers, Hendrik & Sanoamuang, La-Orsri, 2015

Dang, Mau Trinh, Segers, Hendrik & Sanoamuang, La-Orsri, 2015, Psammon rotifers in Central Vietnam, with the descriptions of three new species (Rotifera: Monogononta), Zootaxa 4018 (2), pp. 249-265 : 254-256

Lecane phapi new species

( Figs 3–6, 13–14 )

Type specimens. holotype (IG 33091 RIR 233) and one paratype (IG 33091 RIR 234) in permanent slides, deposited Royal Belgian Institute of Natural Sciences, Brussels, Belgium ( RBINS). Four slides containing one paratype each (SK-R0126-01, -04) deposited in the Science Museum, Khon Kaen University, Khon Kaen, Thailand.

Type locality. Bau Thiem Lake (16°38'6.60"N, 107°21'51.00"E), Phong Binh community, Phong Dien district, Thua Thien Hue province, Vietnam.

Additional material examined. Three specimens from Skull springs, Davis River near Nullagine, Pilbara, West Australia, coll. Oct. 12, 2013 (1 specimen in permanent slide, RBINS IG 33090 RIR 228)

Differential diagnosis. This species is quite unmistakable, but can be confused with L. lunaris (Ehrenberg, 1832) . The acutely pointed antero-lateral spines, projecting foot pseudosegment and complete, lunate transverse fold on the ventral plate distinguish L. phapi n. sp. from L. lunaris . The species also resembles L. kunthuleensis Chittapun, Pholpunthin & Segers, 2003 , L. nigeriensis Segers, 1993 , and L. namatai Segers & Mertens, 1997 by its general lorica shape, parallel-sided toe with a pair of pseudo-claws and accessory claws, and complete, lunate tranverse fold on the ventral plate. However, of all of these only L. phapi has antero-lateral spines and a trapezoidal, distally broadest and strongly projecting foot pseudosegment. In addition, L. phapi n. sp. has parallel ventral and dorsal head aperture margins (biconvex in L. nigeriensis and L. namatai ) and the lateral margins of the dorsal plate reach the anterior margin (not so in L. nigeriensis ).

Description. Female: Lorica stiff. Dorsal plate smooth, anteriorly narrower, medially wider than the ventral plate. Head aperture margins straight. Lateral margins of dorsal plate reach the head aperture margin, antero-lateral corners with well-developed, acutely pointed spines. Ventral plate longer than wide (length:width ca. 1.5), with strong and complete, lunate transverse fold. Lateral margins smooth, nearly parallel. Lateral sulci deep. Foot plate broad, coxal plate rounded triangular. Prepedal fold elongate, distally with broad, rounded projection. Foot pseudosegment trapezoidal, distally broadest. Toe single, parallel-sided, with a pair of incompletely separated pseudo-claws and accessory claws.

Trophi ( Figs. 5–6): Manubria and unci slightly asymmetrical, right-hand side more developed. Fulcrum curved in lateral view, basal plate developed. Unci consisting of three unequal teeth.

Measurements (mean (SD), in Μm): Dorsal Plate length (DPl) 69.3 (3.6), width (DPw) 51.6 (1.8), Ventral Plate length (VPl) 74.4 (3.9), width (VPw) 48 (1.7), Head Aperture width (HAw) 40 (1.7), Toe length (Tl, claw excluded) 28.6 (1.7), (Pseudo)Claw length (Cl) 7 (0.8) and Anterior Spine length (ASl) 2.6 (0.4).

Ecology and distribution. Lecane phapi n. sp. was found during October 2012 (rainy season) and July 2013 (dry season) in hygropsammon samples of Bau Thiem Lake, Thua Thien Hue Province, Vietnam. A few specimens of the species were found in a sample from Skull springs, Davis River near Nullagine, Pilbara, West Australia, collected on October 12th, 2013. Notwithstanding that the sample from Skull springs was collected in open water, we conclude that the species is a psammobiont, on account of its apparent rarity outside of the psammon, and of the observation that psammobionts can occasionally occur in the littoral.

Etymology. The species is named after Dr. Phap Ton That, an associate professor of Hue University of Sciences, Vietnam, in recognition of his moral support to Mau Trinh Dang.

Figures

FIGURES 13 – 14. Lecane phapi n. sp., 13: dorsal, 14: ventral. FIGURES 15 – 16. L. dorysimilis n. sp., 15: dorsal, 16: ventral. FIGURE 17. L. spiniventris Segers, ventral.