Postolata longjiangensis Liu & Zhang & Hou & Ning & Wu 2024, sp. nov.
Creators: name: Liu, Lili
name: Zhang, Liping
name: Hou, Kaiyu
name: Ning, Liyang
name: Wu, Ruiwen
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Bivalvia
Unionida
Unionidae
Postolata
Postolata longjiangensis

description: Postolata longjiangensis Liu & Wu sp. nov.
Fig. 2
Type materials.
Holotype (Fig. 2 E): SXNU_24040702 (length 53.06 mm, height 27.11 mm, width 17.28 mm); Long River, Hechi City, Guangxi Province, China. Paratypes (Fig. 2 A – D, F): five specimens, SXNU_24040703, SXNU_24040705, SXNU_24040706, SXNU_24040704, and SXNU_24040701. Same collection location as the holotype.
Morphological diagnosis.
Postolata longjiangensis sp. nov. can be distinguished from Postolata guangxiensis by the shell shape, beak position, surface sculpture, nacre color, and hinge structure (Table 3). Diagnostic characteristics: shell elongated, irregularly rectangular; the umbo situated at 1 / 4 of the shell length; epidermis brown with greenish tinge; nacre blue-white; and hinge tooth weaker than that of Postolata guangxiensis.
Molecular diagnosis.
Postolata longjiangensis sp. nov. and Postolata guangxiensis formed a closely related group within the tribe Gonideini. The sequences of Postolata longjiangensis sp. nov. revealed a well-supported lineage that is distinct from its congener (Fig. 4). The genetic distance between the new species and Postolata guangxiensis is 8.13 % based on the COI barcoding sequences.
Description.
Shell elongated, irregularly rectangular, slightly thickened, moderately inflated; anterior margin rounded and short; ventral margin nearly straight; posterior margin wide and long; posterior slope significantly prominent; dorsal margin nearly straight, with an upward tilt angle; umbo located at 1 / 4 of the shell length and sculptured with wavy ridges; epidermis brown with greenish tinge; shell surface sculptured with fine concentric growth lines (Fig. 2; Table 3). Anterior adductor muscle attachment oblong, little deep, and smooth; posterior adductor muscle attachment round to oval, shallow, and smooth; anterior retractor muscle attachment completely integrated with anterior adductor muscle attachment; posterior retractor muscle attachment irregularly round and fused with the posterior adductor muscle attachment; mantle muscle attachment obvious. Hinge weakly developed; anterior tooth extremely small, posterior tooth small, thin, and pyramidal in the left valve; anterior tooth upright pyramidal; posterior tooth degenerate and merge into the lateral teeth in the right valve; there is one short lateral tooth of both shells; nacre-bule-white (Fig. 2; Table 3). Papillae in the incurrent aperture short and cylindrical, arranged in two rows; papillae in the excurrent aperture weakly developed, sparsely arranged in one row; and the pigmentation of the incurrent and excurrent aperture significant; the size of inner gills exceeds that of outer gills; labial palps medium-thick, flat elliptical (Fig. 3; Table 3).
Etymology.
This species’ name is dedicated to its collection location, the Long River in Hechi City, Guangxi Province, China. For the common name, we recommend “ Longjiang Rear-wide Mussel ” (English) and “ Long Jiang Hou Ju Bang ” (龙江后矩蚌) (Chinese).
Distribution.
Long River at Hechi City, Guangxi Province, China.
description: Published as part of Liu, Lili, Zhang, Liping, Hou, Kaiyu, Ning, Liyang & Wu, Ruiwen, 2024, Addition to the known diversity of Chinese freshwater mussels: integrative description of a new species of Postolata Dai et al., 2023 (Bivalvia, Unionidae, Gonideinae), pp. 769-778 in Zoosystematics and Evolution 100 (3) on pages 769-778, DOI: 10.3897/zse.100.126069