Eucalathis Fischer & OEhlert, 1890

Hansen, Jesper, 2024, Brachiopods of the Norwegian fauna northern North Atlantic and Arctic, with a focus on, Fauna norvegica 43, pp. 12-68 : 36

Genus Eucalathis Fischer & OEhlert, 1890

collection containing a wide range of shell sizes, population samples and geographically separated material of both species. As expected, the shell shape and ornamentation of both species show strong variability between specimens within the same population, but also along different growth stages of single specimens, with most features varying independently of each other. It can be concluded that the range of variation within each single feature shows a considerable overlap between the two species. The most stable differences surprisingly turned out to be the ornamentation on the umbonal part, especially in specimens 2–10 mm in length.

Due to the past synonymisation and confusion of the two species, the published geographic distribution—especially in the Arctic region—may be based on a mix of the species in many cases. Therefore, in the present study, the more uncertain observations were excluded. Some of the earlier identifications made in the present study are also erroneous since a greater understanding of the value of various diagnostic features evolved along the way. This latter problem has been addressed to some extent by re-examining the specimens from many of the border occurrences.

Material collected from southern Norway during the present century was not available for the present study. Therefore, no