Original paper
Phacoceras oxystomum (Phillips, 1836), an enigmatic Early Carboniferous nautiloid
Korn, Dieter
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen (2025)
43 references
published online: Oct 1, 2025
manuscript accepted: Sep 5, 2025
manuscript received: Aug 31, 2025
DOI: 10.1127/njgpa/1285
Abstract
Phacoceras oxystomum (Phillips, 1836) is, with its extremely discoidal conch and a sharply acute venter, one of the most conspicuous Carboniferous nautiloids. It is re-described here on the basis of a well-preserved specimen from Late Viséan strata of the Rhenish Mountains. The ontogenetic development of the species reveals a rapid transformation from a juvenile stage with morphological features characteristic of the superfamily Subclymenioidea Shimansky, 1962 to the distinct adult stage with an acutely pointed venter. The assignment of the family Phacoceratidae Shimansky, 1962 to this superfamily is therefore supported.
Keywords
Nautilida • Phacoceratidae • Carboniferous • Viséan • Rhenish Mountains