Original paper

Diverse Late Jurassic anomuran assemblages from the Swabian Alb and evolutionary history of paguroids based on carapace morphology

Fraaije, René H.B.

Abstract

From late Kimmeridgian (Late Jurassic) shallow-marine limestones on the Westerberg, close to Nusplingen (Swabian Alb, southern Germany), highly diverse assemblages of anomurans are recorded. The superfamily Galatheoidea is represented by abundant and relatively large cara-paces of Gastrosacus wetzleri, the Paguroidea by comparatively small-sized carapaces, shields and sixth abdominal tergites that are assignable to the families Annuntidiogenidae n. fam., Diogenidae, Gastrodoridae, Parapylochelidae, Pilgrimchelidae n. fam. and Pylochelidae. Such diverse Mesozoic paguroid assemblages have never been recorded previously; they provide evidence of the relative abundance and diversity of paguroids in Late Jurassic shallow-marine settings. Species recorded are: Ammopylocheles mclaughlinae, Ammopylocheles petersi n. sp., Annuntidiogenes jurassicus n. sp., Gastrodorus spp., Housacheles ovalis n. sp., Jurapylocheles iwonae, Masticacheles minimus n. sp., Mesoparapylocheles schweigerti n. sp., Mesoparapylocheles jaegeri n. sp., Parapylochelitergites deductius n. sp., Parapylochelitergites prepustulosus n. sp., Pilgrimcheles kersteni n. sp., Pilgrimcheles vonmeyeri n. sp., Pylochelitergites westerbergensis, Scututergites anteroindentatus n. gen., n. sp., Stagmacaris subcircularis n. sp. and Ululapagurus vanbakeli n. gen., n. sp. The phylogenetic state-of-the-art, as based on carapace morphologies of Mesozoic carapace-based paguroid species known to date is outlined. The average size of Late Jurassic paguroid carapaces is considerably lesser than that of co-occurring brachyurans and galatheoids. Their small size and incomplete preservation of carapaces, with mostly only (part of) the shield retained, explains why fossil paguroids are very often overlooked in the field.

Keywords

anomuragalatheoidealate jurassicnew taxapaguroideaphylogeny