Batrachotomus

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Batrachotomus
Temporal range:
Ma
↓
Reconstructed skeleton, Staatliches Museum für Naturkunde Stuttgart
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Loricata
Genus: †Batrachotomus
Gower, 1999
Species:
†B. kupferzellensis
Binomial name
†Batrachotomus kupferzellensis
Gower, 1999

Batrachotomus

palaeontologist David J. Gower
22 years after its discovery.

The locality where Batrachotomus lived was a swampy region and the name comes from the

dinosaurs
.

Description

Artist's life restoration
Size comparison of Batrachotomus

Batrachotomus was a heavily built, large quadrupedal reptile reaching 6 metres (20 ft) in length. A trait that characterized Batrachotomus, compared to other

osteoderms.[3] Flattened and leaf-shaped, these extended from behind the head along the column and reducing in size, ended at the tail.[3] There is also evidence that osteoderms were present on the ventral region of the tail, as seen in Ticinosuchus ferox, and even on the flank, belly and limbs.[3][4]

Like

metatarsal (bone in hindlimbs attached to the toe bones) which was hooked in shape.[3] However, hypotheses suggest that probably each forelimb had four toes and each hindlimb five.[6]

Skull, Staatliches Museum für Naturkunde Stuttgart

Batrachotomus had a tall and narrow skull estimated at 40 to 50 cm (1.3 to 1.6 ft) in length.

fenestrae (skull openings), two pairs of which were for the eyes (called orbits) and the nostrils. Behind the orbits were two temporal fenestrae. These holes probably helped to reduce the weight of the skull and enabled the jaw to open more widely.[8] As a typical archosaur, Batrachotomus had two antorbital fenestrae
between the orbits and nostrils, and a fifth pair of small openings at the rear part of the lower jaw.

The jaws contained sharp teeth which were compressed laterally and unequal in size and shape,

heterodonty.[7][10] The teeth on the premaxillae (bones at the very tip of the upper jaw) were slender, unlike those of the maxillae (the main tooth-bearing bones in the upper jaw) which had a straight posterior edge.[11] The upper jaw bore 30 teeth, with each premaxilla carrying about 4 teeth and each maxilla 11, while the lower jaw held 22 teeth.[9]

Discovery and history

The Kupferzell locality in Germany, where fossils of Batrachotomus have been discovered.

Remains of Batrachotomus have been found in southern Germany, mainly in the Kupferzell fossil locality in northern Baden-Württemberg. Fossil collector Johann G. Wegele discovered the first specimens in a 1977 excavation at the Erfurt Formation, dated from the Longobardian (late Ladinian) age.[12][13] Other remains attributed to Batrachotomus have been collected in Vellberg-Eschenau, about 10 km east of Schwäbisch Hall, and in Crailsheim. The most notable are from Vellberg-Eschenau, which are represented by well preserved ribs and vertebrae (MHI 1895), and evidence of forelimbs and hindlimbs (SMNS 90018).[13] Batrachotomus today is displayed in the Muschelkalk Museum, Ingelfingen, Stuttgart.

The fossils recovered from a

marlstone remained undescribed until 1999 and palaeontologists referred to the genus simply as "rauisuchid" or "Kupferzellia".[7][12] In 1999, palaeontologist David J. Gower described the holotype (SMNS 52970) from the 1977 excavation, which is the largest specimen of the genus,[12][13] comprised by incomplete skull and postcranial material.[1] Anatomy of the braincase (SMNS 80260) was made three years later, shedding light on the evolutionary relationships of the poorly known group of Rauisuchia.[14] In 2009, Gower and Rainer R. Schoch reported a detailed reconstruction of the postcranial skeleton for the first time.[15]

Classification

Skeletal elements, Museum am Lowentor, Stuttgart

Batrachotomus was a prestosuchid, a member of a family of carnivorous archosaurs within the larger group Rauisuchia. The family name "Prestosuchidae" was established in 1966 by American paleontologist Alfred Romer. Prestosuchids were quadrupedal reptiles, medium to large in size, characterized by erect posture, large and narrow skull and large antorbital openings.[16]

Attention was first brought to Batrachotomus in 1993 by

Benton and Walker, showing the close relationships between Batrachotomus and Prestosuchus, led to the transfer of Batrachotomus to the family Prestosuchidae.[14][18]

Sterling J. Nesbitt (2011) revised the

sister taxon of Batrachotomus using a derivative of Nesbitt (2011) analysis.[22]

The cladogram below follows an analysis by Sterling J. Nesbitt (2011):[23]

Model (background) in Triassic environment
Archosauria
 

Paleoecology

Since 1977, the rich vertebrate fauna found at Baden-Württemberg reflects a moist region of the Middle Triassic in Germany. Along with Batrachotomus, palaeontologists recovered remains of fishes, amphibians, such as

horsetails, ferns, cycads and conifers, suggesting that there was rich vegetation.[24]

References

Notes
  1. ^ a b Gower (1999), p. 6.
  2. ^ Gower (1999), p. 1.
  3. ^ a b c d e f Gower and Schoch (2009), p. 117.
  4. ^ Gower and Schoch (2009), p. 104.
  5. ^ Gower and Schoch (2009), p. 109.
  6. ^ Gower and Schoch (2009), p. 119 (Figure 8).
  7. ^ a b c d e Gower (1999), p. 7.
  8. ^ Benton (2005), p. 112.
  9. ^ a b Gower (1999), p. 37.
  10. ^ Gower (1999), p. 38.
  11. ^ Gower (1999), pp. 37–38.
  12. ^ a b c d Gower (1999), p. 5.
  13. ^ a b c Gower and Schoch (2009), p. 121.
  14. ^ a b Gower (2002), p. 49.
  15. ^ Gower and Schoch (2009), p. 103.
  16. ^ Sill (1974), p. 317.
  17. ^ Parrish (1993), p. 301.
  18. ^ Benton and Walker (2002), pp. 40–41.
  19. S2CID 83493714
    .
  20. S2CID 86797826
    .
  21. doi:10.1111/zoj.12038
    .
  22. S2CID 210915628
    .
  23. S2CID 83493714
    .
  24. ^ Rozynek (2008), p. 4.
Sources

External links
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