English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The genus Calyptogena (Bivalvia: Vesicomyidae) comprises highly specialized bivalves living in symbiosis with sulphur-oxidizing bacteria in reducing habitats. In this study, the genus is revised using shell and anatomical features. The work is based on type material, as well as on the extensive collection of vesico- myids obtained,during twelve expeditions to the Pacific and Indian Oceans. Nine Recent species are ascribed to the genus Calyptogena, four of which are new: C. pacifica Dall, 1891, C. fausta Okutani, Fujikura & Hashimoto, 1993, C. rectimargo Scarlato, 1981, C. valdiviae (Thiele & Jaeckel, 1931), C. gallardoi Sellanes & Krylova, 2005, C. goffrediae n. sp., C. starobogatovi n. sp., C. makranensis n. sp. and C. costaricana n. sp. The characteristic features of Calyptogena are: shell up to 90 mm in length, elongate-elliptical or elongate; presence of escutcheon; presence of broad posterior ramus,(3b) of right subumbonal,cardinal tooth as well as right posterior nymphal,ridge; absence of pallial sinus as a result of attachment,of inter- siphonal septal retractor immediately,adjacent to ventral surface of posterior adductor; absence of pro- cesses on inner vulva of inhalant siphon; presence of inner demibranch only, with descending and ascending,lamellae with interlamellar septa not divided into separate tubes. The most closely related taxa to Calyptogena are probably the genus Isorropodon Sturany, 1896, and the group of species rep- resented by ‘Calyptogena’ phaseoliformis Me´ tivier, Okutani & Ohta, 1986. These groups have several char- acters in common, namely absence of pallial sinus, presence of single inner pair of demibranchs and absence,of processes on inner vulva of inhalant,siphon. The worldwide,distribution of the genus Calyptogena suggests that methane,seeps at continental margins,are the major,dispersal routes and that speciation was promoted,by geographical,isolation. Recent species diversity and fossil records indi- cate that the genus originated in the Pacific Ocean. Sufficient data to discuss the distribution at species level exist only for C. pacifica, which has a remarkably narrow bathymetric range. Published studies on the physiology of C. pacifica suggest that adaptation,to a specific geochemical,environment,has led to coexisting vesicomyid,genera. The bacteria-containing gill of C. pacifica and other Calyptogena species is one of the most specialized in the family Vesicomyidae,and may,reflect these ecological adaptations.

Recent bivalve molluscs of the genus Calyptogena (Vesicomyidae)