Lepadella wilungulai Luo & Segers 2020

Lepadella wilungulai n. sp Figures 9 a–c, I-6 Type locality. Lulu River near Basoko, DR Congo 21 May 2010 (KM27). Material examined. Holotype: one female specimen in permanent slide, deposited in RBINS (RIR.320). Differential diagnosis. The three exceptionally well-developed dorsal carinae of L. wilungulai n. sp. distinguish the species unequivocally from all congeners. The only species with which the animal might be compared is L. donneri Koste, 1972 which has very similar lateral carinae but which lacks the dorsal carina and which has a more rounded lorica. A third, unnamed Neotropical relative recorded by Koste & Böttger (1992) as “ Lepadella quinquecostata nov. forma?” and by José de Paggi (2001) as L. quinquecostata also has extraordinarily developed carinae, but this animal has five, less developed and differently situated carinae, is larger, and has a differently shaped lorica. Differential diagnosis. Parthenogenetic female (male unknown): Lorica elongate, roughly egg-shaped, width about two thirds of length. Ventral lorica nearly flat, dorsal domed, lorica about twice as wide as high. Head aperture ventrally a deep U-shaped sinus, dorsally semi-circular in anterior view, a broad U-shaped sinus in ventral view, with collar. Dorsal lorica with three longitudinal carinae: one median, and a pair of lateral carinas running from the anterior tips of the lorica to just anterior of the apertures to the dorsal antennas. Dorsal carina extremely high and narrow. Lateral edges of lorica smooth, evenly curved, posterior edge with a minute convex projection as extension of the dorsal carina. Apertures to the lateral antennas situated at the level of the anterior margin of the foot aperture, arranged symmetrically about medially from the middorsal carina to the lateral margin of the lorica. Foot aperture elongate, lateral margins nearly parallel. Foot with three distinct pseudosegments, the distal one about thrice as long as the second, bearing a dorsal sensory groove near its basis. A pair of equal-sized toes present, these almost parallel-sided proximally, more strongly tapering from about midway to distally. Measurements (n=1). Lorica length: 117, width: 86; Head aperture width: 24, head aperture depth dorsally: 8, ventrally: 19, Foot aperture width: 16, length: 30, toe length: 33. Etymology. The specific name is as a noun in the genitive case, dedicated to Dr Father Cosma Wilungula, Executive director of the Institut Congolais pour la Conservation de la Nature, in recognition of his contribution to nature conservation in the Democratic Republic of Congo. Remark. We acknowledge that describing and naming a new rotifer species based on a single specimen is a practice frowned upon, for good reasons, by numerous authorities including, e.g., Ruttner-Kolisko (1989) and Koste & Shiel (1989). However, the unique features of the holotype, the outstandingly easy diagnosis and the potential biogeographical relevance of the animal convince us to exceptionally proceed with the description and establishment of a new name for the single specimen discovered.
Published as part of Luo, Yongting & Segers, Hendrik, 2020, Eight new Lepadellidae (Rotifera, Monogononta) from the Congo bring to level endemism in Africa's rotifers, pp. 371-387 in Zootaxa 4731 (3) on page 377, DOI: 10.11646/zootaxa.4731.3.6, http://zenodo.org/record/3653632
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