Lecane langsenensis, Trinh-Dang & Phan & Vo, 2019

Trinh-Dang, Mau, Phan, Doan Dang & Vo, Van Minh, 2019, A new rotifer species: Lecane langsenensis n. sp. (Rotifera: Monogononta) from Vietnam, Zootaxa 4615 (1), pp. 155-164 : 157-159

Lecane langsenensis new species

( Figure 3 and Figures 4 A–B)

Type specimens: the holotype (SMT-R0222-01) and two paratypes (SMT-R0222-02, SMT-R0222-03) on permanent slides were deposited in the Biological Museum, University of Science and Education, Danang University. Two slides containing one paratype per slide (ITB-CZ-R00018-01, ITB-CZ-R00018-02) were deposited in the Institute of Tropical Biology , Vietnam Academy of Science and Technology .

Type locality: Huong River , Hue City, Thua Thien Hue Province, Vietnam , and Lang Sen Reserve , Tan Hung District, Long An Province, Vietnam .

Differential diagnosis: Lecane langsenensis n. sp. may be confused with L. aculeata ( Figure 4C ), L. arcula ( Figure 4F ) and L. superaculeata ( Figures 4 D–E) but is characterized by a relatively more elongated lorica (length: width of dorsal plate = 1.29 in L. langsenensis , 1.12 in L. arcula , 1.19 in L. aculeata , and 1.11 in L. superaculeata and length:width of ventral plate = 1.52 in L. langsenensis , 1.37 in L. arcula , 1.48 in L. aculeata , and 1.39 in L. superaculeata ), longer antero-lateral spines (15.23±1.82 μm in L. langsenensis , 13.62±0.79 μm in L. superaculeata , 11.06±1.74 μm in L. aculeata , and 4.88±0.47 μm in L. arcula ), and longer claws (9.49±0.78 μm in L. langsenensis , 5.98±0.99 μm in L. superaculeata , 5.38±0.77 μm in L. aculeata , and 4.19±0.51 μm in L. arcula ). L. langsenensis can be distinguished from L. aculeata and L. arcula by antero-lateral spines formed by the ventral plate, whereas these spines are clearly separated from the ventral plate in L. aculeata and L. arcula . L. langsenensis differs from L. superaculeata in having a less ornamented lorica and inwardly curved antero-lateral spines.

Description: Female: Lorica stiff. Dorsal plate quite smooth, anteriorly narrower, medially wider than the ventral plate. Head aperture margins nearly coincident, straight. Lateral margins of the dorsal plate reaching the head aperture margin. Ventral plate longer than wide, with incomplete transverse and longitudinal folds. Lateral margins smooth, parallel-sided. Antero-lateral spines exceptionally long and slightly curved inwards. Lateral sulci shallow. Foot plate wide, with a rounded triangular coxal plate. Prepedal folds narrow, elongated, distally with a median projection. Foot pseudosegment projecting, slightly trapezoidal, with lateral lobes. Toes parallel-sided, bearing long claws completely separated, needle-like. Accessory claws present.

Male unknown.

Trophi ( Figure 3C ): fulcrum straight and elongated. Rami asymmetrical. Unci consisting of three unequal teeth, slightly asymmetrical, right-hand side more developed. Manubria elongated, curved distally.

Measurements (mean (SD), in μm): dorsal plate length (DPl) = 63.12 (2.44), dorsal plate width (DPw) = 48.91 (1.74), ventral plate length (VPl) = 70.12 (2.04), ventral plate width (VPw) = 46.26 (2.10), head aperture width (HAw) = 43.34 (1.43), toe length (Tl, claw excluded) = 22.68 (1.45), (pseudo)claw length (Cl) = 9.49 (0.78) and anterior spine length (ASl) = 15.23 (1.8).

Ecology and distribution: Lecane langsenensis n. sp. was found in Lang Sen Reserve , Tan Hung District , Long An Province, Vietnam. The area is a typical wetland swamp and has a rich submerged macrophyte community in the sublittoral zone. The environmental characteristics of the Lang Sen Reserve are as follows: pH of 3.47, temperature of 31.7 °C, dissolved oxygen (DO) of 5.2 mg /l, and electrical conductivity (EC) of 1.19 mS. Three specimens of the species were found in a sample from the Huong River near Thien Mu pagoda, Thua Thien Hue Province, Vietnam, in July 2018. No environmental characteristics of the Huong River were recorded during sampling .

Etymology: The name of this species is an adjective and refers to the type locality of the animal, Lang Sen Reserve.

Figures

FIGURE 3. Lecane langsenensis n. sp.; A: dorsal view, B: ventral view, C: trophi.

FIGURE 4. A–B: Lecane langsenensis n. sp.; A. dorsal view. B. ventral view. C. Lecane aculeata habitus, ventral view. D–E: Lecane superaculeata habitus; D. dorsal view, E. ventral view. F: Lecane arcula habitus, ventral view.