Gouldiinae, Stewart, 1930

Liu, Yumeng, Ma, Peizhen, Zhang, Zhen, Li, Cui, Chen, Ya, Wang, Yunan & Wang, Haiyan, 2022, The new phylogenetic relationships in Veneridae (Bivalvia: Venerida), Zoological Journal of the Linnean Society 196, pp. 346-365 : 360-361

Gouldiinae

The relationship between Gafrarium tumidum Röding, 1798 and Gafrarium pectinatum (Linnaeus, 1758) is not yet well clarified. Huber (2010) proposed Gafrarium tumidum as a subtype of Gafrarium pectinatum , based on morphological similarities. At present, Gafrarium tumidum is accepted as a synonym of Gafrarium pectinatum in the World Register of Marine Species (https://www.marinespecies.org). However, a significant difference in cox1 sequences (identity percentage <90%) is detected, in addition to obvious differences in radial ribs of the two species. In Gafrarium pectinatum , the radial ribs in the middle of the shell surface have uneven thickness and are always merged or bifurcated ( Fig. 11A ), whereas in Gafrarium tumidum the radial ribs in the middle of the shell thicken from the umbo to the ventral margin, and every two ribs cluster together, with secondary ribs near the ventral margin between clusters ( Fig. 11B ). According to our molecular and morphological findings, we confirm that Gafrarium tumidum is a valid species.

Our phylogenetic results also suggest placing the genera Lioconcha Mörch, 1853 and Hyphantosoma Dall, 1902 in Gouldiinae . Reeve (1863) proposed that Lioconcha was much closer to Circe Schumacher, 1817 / Gafrarium Röding, 1798 than to Pitar Römer, 1857 . Huber (2010) also indicated that all Lioconcha species have a small pallial sinus, which is a typical characteristic of Gouldiinae . Moreover, Hyphantosoma is characterized by a zigzag sculpture on the external surface of the shell ( Hertlein & Strong, 1948; Lamprell & Healy, 1997; Raines & Huber, 2012), similar to the sculpture of Circe . Thus, it is reasonable to place these two genera in Gouldiinae and consider Lioconchinae as a synonym of Gouldiinae .

Figures

Figure 11. Shell of Gafrarium pectinatum (A) and Gafrarium tumidum (B).