Patterns of larval development in the Anura: palaeontological evidence

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Patterns of larval development in the Anura
palaeontological evidence

• Zbynek Rocek and Eddie Van Dijk

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Bechlejovice, Late Oligocene, -32 Mya,
Czech Republic
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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).
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Skeletal development of Xenopus
Stage 57
Stage 56
Stage 54
Stage 52
Stage 46
Stage 60
Stage 66
Stage 59
Stage 60
Stage 63
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Skeletal development of Palaeobatrachus
The earliest preserved larva Nieuwkoop and Faber
(1967) stage 58
Xenopus laevis Nieuwkoop and Faber (1967) stage
59
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Skeletal development of Palaeobatrachus
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Skeletal development of Palaeobatrachus
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Skeletal development of Palaeobatrachus
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Skeletal development of Palaeobatrachus
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Skeletal development of Palaeobatrachus
Gigantism in metamorphosing tadpoles
Stage 60
16 cm
Miocene (approx. 15 Mya) Randecker Maar, Germany
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Skeletal development of Palaeobatrachus
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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.
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Makhtesh Ramon, Early Cretaceous, cca 130
Mya, Israel
Thoraciliacus rostripes holotype
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Skeletal development of Thoraciliacus
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Shomron Region, Early Cretaceous, -130 Mya, Israel
Shomronella jordanica
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Skeletal development of Shomronella
?
Adult
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Skeletal development of a pipid from Stompoor
Stompoor (crater lake deposits) Late Cretaceous,
-150 Mya South Africa
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Xenopus hasaunus Early Oligocene, cca -35 Mya
Libya
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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.
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Skeletal development of Pelobates
Stage 52
Stage 53
Stage 56
16 cm
Stage 64
Stage 66
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Skeletal development of Eopelobates
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Skeletal development of Eopelobates
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The oldest known tadpoles
Late Jurassic, -150 Mya Zaire
University of Stellenbosch, South
Africa Palaeontological collections Cat. No. 493
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Late Jurassic, 150 Mya or early Cretaceous, 128
mya Ningcheng, Inner Mongolia, China
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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.