Patterns of larval development in the Anura palaeontological

Patterns of larval development in the Anura: palaeontological evidence Zbyněk Roček and Eddie Van Dijk

Bechlejovice, Late Oligocene, -32 Mya, Czech Republic

Palaeobatrachidae - the only anuran group that became extinct; - Late Cretaceous – Middle Pleistocene (-70 -0. 9 Mya); - found only in Europe; - similar to pipid frogs of southern hemisphere but different in procoelous, instead of opisthocoelous, vertebral centra; - the most representative developmental series of fossil frogs ever found (covering late larval development and complete metamorphosis).

Skeletal development of Xenopus Stage 46 Stage 59 Stage 52 Stage 60 Stage 54 Stage 60 Stage 56 Stage 63 Stage 57 Stage 66

Skeletal development of Palaeobatrachus The earliest preserved larva Nieuwkoop and Faber (1967) stage 58 Xenopus laevis Nieuwkoop and Faber (1967) stage 59

Skeletal development of Palaeobatrachus

Skeletal development of Palaeobatrachus

Skeletal development of Palaeobatrachus

Skeletal development of Palaeobatrachus

Skeletal development of Palaeobatrachus Gigantism in metamorphosing tadpoles Stage 60 16 cm Miocene (approx. 15 Mya) Randecker Maar, Germany

Skeletal development of Palaeobatrachus

Comparisons with fossil Pipidae - the earliest tadpoles ever found (Late Jurassic, -150 Mya, Zaire); - sometimes excellent preservation; - found only in Gondwanan continents; - large series of certain developmental stages.

Makhtesh Ramon, Early Cretaceous, cca 130 Mya, Israel Thoraciliacus rostripes holotype

Skeletal development of Thoraciliacus

Shomron Region, Early Cretaceous, -130 Mya, Israel Shomronella jordanica

Skeletal development of Shomronella ? Adult

Skeletal development of a pipid from Stompoor (crater lake deposits) Late Cretaceous, -150 Mya South Africa

Xenopus hasaunus Early Oligocene, cca -35 Mya Libya

Pelobatidae - represented by genera Pelobates and Eopelobates; - fossil record from the Paleocene (-60 Mya); - found only in Europe; - developmental series covering both pre-metamorphic and metamorphic stages.

Skeletal development of Pelobates Stage 52 Stage 53 16 cm Stage 64 Stage 66 Stage 56

Skeletal development of Eopelobates

Skeletal development of Eopelobates

The oldest known tadpoles Late Jurassic, -150 Mya Zaire University of Stellenbosch, South Africa Palaeontological collections Cat. No. 493

Late Jurassic, 150 Mya or early Cretaceous, 128 mya Ningcheng, Inner Mongolia, China

Conclusions - fossil tadpoles may provide an important information on development of extinct anuran taxa; - although the development is mostly documented by ossified elements, sometimes astonishing details of soft anatomy may be recorded; - developmental processes, such as origin of vertebral centra or transverse processes, may help to clarify the taxonomic position of studied taxa and their phylogenetic distance.