PT  - JOURNAL ARTICLE
AU  - Ben Thuy
AU  - Lea D. Numberger-Thuy
AU  - Tania Pineda-Einríquez
TI  - New fossils of Jurassic ophiurid brittle stars (Ophiuroidea; Ophiurida) provide evidence for early clade evolution in the deep sea
AID  - 10.1101/2021.06.03.446910
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.06.03.446910
4099  - http://biorxiv.org/content/early/2021/06/03/2021.06.03.446910.short
4100  - http://biorxiv.org/content/early/2021/06/03/2021.06.03.446910.full
AB  - Understanding of the evolutionary history of the ophiuroids, or brittle stars, is hampered by a patchy knowledge of the fossil record. Especially the stem members of the living clades are poorly known, resulting in blurry concepts of the early clade evolution and imprecise estimates of divergence ages. Here, we describe new ophiuroid fossil from the Lower Jurassic of France, Luxembourg, and Austria and introduce the new taxa Ophiogojira labadiei gen. et sp. nov. from lower Pliensbachian shallow sublittoral deposits, Ophiogojira andreui gen. et sp. nov. from lower Toarcian shallow sublittoral deposits, and Ophioduplantiera noctiluca gen. et sp. nov. from late Sinemurian to lower Pliensbachian bathyal deposits. A Bayesian morphological phylogenetic analysis shows that Ophiogojira holds a basal position within the order Ophiurida, whereas Ophioduplantiera has a more crownward position within the ophiurid family Ophiuridae. The position of Ophioduplantiera in the evolutionary tree suggests that family-level divergences within the Ophiurida must have occurred before the late Sinemurian, and that ancient slope environments played an important role in fostering early clade evolution.Competing Interest StatementThe authors have declared no competing interest.