Lanlabeo, Yao & He & Peng, 2018

Yao, Min, He, You & Peng, Zuo-Gang, 2018, Lanlabeo duanensis, a new genus and species of labeonin fish (Teleostei: Cyprinidae) from southern China, Zootaxa 4471 (3), pp. 556-568 : 559-560

Lanlabeo , gen. nov.

( Figs. 2–3 )

Type species. Lanlabeo duanensis , sp. nov.

Diagnosis. Lanlabeo is diagnosed from all other labeonin genera by the following combination of characters: 1) frenum connecting upper jaw and lower lip at corner of the mouth; 2) papillae densely scattered over ventral margin of rostral cap and regularly arranged; 3) upper lip vestigial; 4) rostral cap overlying upper jaw, with its posterior margin fimbriate; 5) lower lip divided into two small lateral and translucent fleshy lobes and one central plate; 6) median lobe of lower lip large, with papillae regularly arranged in many transverse rows ( Fig. 2 ).

Comparison. Among the described genera of Labeonini, the morphology of this new genus appears to most closely resemble that of Rectoris posehensis ( Lin 1935) . It distinctly differs from this genus, however, in having a pair of well-developed maxillary barbels and in its lower lip being divided into two small lateral and translucent fleshy lobes and one central plate. There are no known cyprinids with mouths of similar structure to that of the fish of this new genus. In the lower jaw of the new genus, the dentary is transversely L-shaped in ventral view, as the anterior part forms a right-angle turn and the transverse branch is anterioposteriorly expanded ( Fig. 4B ). These unique osteological characters can distinguish it from other known genera. Additionally, molecular analyses indicated that this new genus forms a distinct lineage within the Labeonini ( Fig. 5 ).

Etymology. The generic name is made from a combination of the Chinese family name Lan, after Jiahu Lan for his contributions to the discovery of fish diversity in southern China, and the Latin word Labeo , a generic name commonly utilized suffix for the labeonin genera.

Figures

FIGURE 2. Oromandibular structures of Lanlabeo duanensis sp. nov., SWU20170110006, 90.3 mm SL.

FIGURE 3. Lanlabeo duanensis sp. nov., SWU20170110002, paratype, 142.6 mm SL. Collected from the Hongshuihe River in Du’an County, Guangxi Province, southern China. (A) Lateral, (B) dorsal, and (C) ventral views.

FIGURE 4. Head skeleton and pharyngeal dentition of Lanlabeo gen. nov. holotype, SWU 20170110002 (A–E), Rectoris posehensis 3# (F–J), and Ptychidio jordani 1# (K–O). Abbreviations: den, dentary; pcl, postcleithrum. A, F, and K in lateral view; B, G, and L in ventral view; C, H, and M in anterior view; D, E, I, J, N, and O in oblique-dorsal view. Scale bars: 3.0 mm in A, B, F, G, K, and L; 1.5 mm in C, D, E, M, N, and O; 0.9 mm in H, I, and J. Pcl=pectoral; den=dentary.

FIGURE 5. Phylogenetic tree derived from Bayesian analysis of the nuclear genes RAG1, IRBP, RH, and EGR2B. The nodal numbers are Bayesian posterior probabilities and ML bootstrap values, respectively. Only nodes with bootstrap values above 50% are shown.