Postolata longjiangensis Liu & Wu, 2024

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), Zoosystematics and Evolution 100 (3), pp. 769-778 : 769-778

publication ID

https://doi.org/ 10.3897/zse.100.126069

publication LSID

lsid:zoobank.org:pub:354401E7-E9A4-45FD-83DA-876BB4A09650

DOI

https://doi.org/10.5281/zenodo.11638114

persistent identifier

https://treatment.plazi.org/id/AE6B0B64-78A8-5767-96E7-818FCE1C6D03

treatment provided by

Zoosystematics and Evolution by Pensoft

scientific name

Postolata longjiangensis Liu & Wu
status

sp. nov.

Postolata longjiangensis Liu & Wu sp. nov.

Fig. 2 View Figure 2

Type materials.

Holotype (Fig. 2 E View Figure 2 ): 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 View Figure 2 ): 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 View 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 View Figure 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 View Figure 2 ; Table 3 View 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 View Figure 2 ; Table 3 View 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 View Figure 3 ; Table 3 View 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.

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

Order

Unionida

Family

Unionidae

Genus

Postolata