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Zalmoxes
Temporal range: Late Cretaceous
Zalmoxes dichotomy Nihan
A restoration of Zalmoxes robustus and shqiperorum
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
clade: Dinosauria
Superorder: Ornithopoda
Genus: Zalmoxes
Weishampel et al. 2003
Type species
Zalmoxes robustus
Nopcsa, 1899
Referred species
  • Z. robustus Nopcsa, 1899
  • Z. shqiperorum Weishampel et al., 2003
  • Unnamed Weishampel et.al, 2003

Zalmoxes is a genus of rhabdodontid ornithopod dinosaur from the Maastrichtian stage of Romania. This genera is known from specimens first named as the species Mochlodon robustum in 1899 by Franz Nopcsa before being reclassified as Rhabdodon robustum by him in 1915.

In 1990 this name was corrected to Rhabdodon robustus by George Olshevsky, and in 2003 the species was once more reclassified, this time as the type species Zalmoxes robustus. Zalmoxes refers to the Dacian deity Zalmoxis, and robustus to the robustness of the remains. In 2003 another species was named, Zalmoxes shqiperorum, named for the Albanian name for Albanians.

Discovery[]

Zalmoxes skull

Z. shqiperorum reconstructed skull

Zalmoxes was first found in Transylvania known from various fossils, which were given the name Mochlodon robustus by Baron Franz Nopcsa in 1899. The specific name referrers to it's robust build. Later in 1915 Nopsca renamed the Genus as Rhabdodon robustum revised in 2003 by David B. Norman, David B. Weishampel, Zoltan Csiki, and Coralia-Maria Jianu. Weishampel et al. (2003) published a paper on the new remains which they found in Romania, it also represented a new species, Zalmoxes shqiperorum. They found R. robustus was sufficiently different from Rhabdodon, and then named the new genus Zalmoxes for the former. The genus refers to the Dacian deity Zalmoxis (sometimes also spelled Zalmoxes) who retreated for three years in a crypt to be resurrected on the fourth year; similarly the animal Zalmoxes had by Nopcsa been liberated from its fossil grave to attain taxonomic immortality.

The article further explained this by referring to a Greek legend according to which Zalmoxis was a slave of Pythagoras who travelled to Dacia and was defined by the Dacian people. In addition to this, Weishampel et al. named the new species Zalmoxes shqiperorum after Shqiperia, the Albanian name for Albania, which Nopsca had a special relationship with.

Description[]

Zalmoxes is a fairly small genus of bipedal herbivore with a large beak and triangular head. Z. shqiperorum is the larger species, known from a subadult that was 2.5 m (8.2 ft) long, and an early juvenile that was 1.2 m (3.9 ft) long. while subadults of Z. robustus range from 2–2.4 m (6.6–7.9 ft) long. An unnamed third species of Zalmoxes was 9.5 ft (2.9 m) long as adults.

Even though Nopcsa thought the small size of Zalmoxes was due to island dwarfism, Attila Ösi and colleagues found it was closer to the size of the rhabdodontid ancestor, with Larger Rhabdodon and and smaller Mochlodon having island gigantism and island dwarfism, respectively. However when the species of Zalmoxes are taken into account separately, it is seen that Z. shqiperorum continued the general size trend from Orodromeus to Tenontosaurus, whilst Z. robustus may have had a little dwarfism.

Zalmoxes robustus is known from roughly 80% of the skull, But no complete articulated skull is known. and most of the non-overlapping bones are found in isolation Weishampel et al. discovered that these likely represented one individual, since the bones were from the same formation and are the same color. Four individuals were identified Nopcsa for Z. robustus, and from these it can be seen that there is skeletal variation in the species. Like with the cranium material, Z. robustus are often found isolated. All areas of the vertebral column are represented in the fossil record although no sternal plates have been found yet and the sacrum includes five vertebrae, with two sacrodorsals and three sacrocaudals. The limb and girdle bones are also well represented, with only the hands and feet mostly lacking.

Clipboard08

Zalmoxes robustus reconstruction

While less better known, Z. shqiperorum is still known from a relatively large amount of skeleton, only two mostly complete skeletons are known the holotype adult, and a referred juvenile. The dentary of Z. shqiperorum is shorter relatively than the equivalent in Z. robustus although it is much larger, ossified tendons have also been found from the juvenile specimen, showing that they were circular or elliptical in cross section and have fine striations in Z. shqiperorum. Cervicals, dorsals, and caudal vertebrae have been found from Z. shqiperorum, though the former two are only represented by juvenile material. A complete articulated sacrum is known for Z. shqiperorum, with three vertebrae and two sacrodorsals. No manual (Hand) material is known from the species, although a metatarsal and a few phalanges have been found.

Classification[]

The genera Mochlodon Zalmoxes, and Rhabdodon had long had an uncertain phylogenetic placement, being referred to various families. Nopcsa (1901) contemplated Mochlodon as being within Kalodontidae, a family since then considered paraphyletic. Nopcsa (1901) also had referred the genus to Hypsilophodontidae, and he suggested affinities with Camptosaurus in 1902b, 1904, and 1915. Nopcsa (1915) also realized that Rhabdodon and Mochlodon may be congeneric, placing the complex in Camptosauridae. For the next half-century, taxonomic workers found Rhabdodon and Mochlodon to be either within Camptosauridae or Iguanodontidae. in the 80's and 90's, paleontologists realized Rhabdodon had already been in use by a snake, and thus used Mochlodon for all the remains of either genera, placing it as hypsilophodontid or dryosaurid. However Pula Sereno (1986) found that Rhabdodon and Mochlodon were in Iguanodontia.

The ICZN (1988) resolved this complication, choosing Rhabdodon as having priority over Mochlodon. From this publication scientists began placing Rhabdodon and Mochlodon within Euornithopoda. Later in 2003 Weishampel et al. named a new family for Mochlodon, Rhabdodon and the new genus Zalmoxes, Rhabdodontidae which was placed as derived within Iguanodontia. Further studies support this placement of Rhabdodontidae, phylogenetically between Talenkauen and Tenontosaurus.

Paleobiology[]

Zalmoxes is a more robustly built animal than its precursors and more derived relatives, and it has a rotund build. Infraspecific ontogenetic growth is relatively well known in Zalmoxes as there is juvenile material known for the species. Nopcsa suggested that the animals of Hateg Basin which were smaller than their relatives elsewhere, suffered from insular dwarfism. Fossils of both species of Zalmoxes have been unearthed in the Sânpetru Formation, the Sebes Formation and Densuş-Ciula Formation in Romania, both species have been found exclusively in the Hațeg Island region.

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