Protosyngnathus
| Protosyngnathus Temporal range:
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|---|---|
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Syngnathiformes |
| Genus: | †Protosyngnathus |
| Species: | †P. sumatrensis
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| Binomial name | |
| †Protosyngnathus sumatrensis von der Marck, 1876
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Protosyngnathus is a genus of syngnathiforms that come from Sangkarewang Formation, Sumatra (Indonesia). Its first specimen was found in Ombilin Basin, which is an Eocene aged deposit, that is mostly complete. Later five more specimens were found that were kept in Natural History Museum, London[1]
From the discovered specimens, it can be inferred that Protosyngnathus measured 33,8 cm in standard length. The head takes up to 26,6% of its standard length . The skull bear an ornamentation of closely spaced, small rounded tubercles that radiate in rows from the ossification centres to cover the entire bone. For the dentary, the holotype show that Protosyngnathus have long and low dentary with a few, small conical teeth[1]
The body have V-shaped scutes that run in series along the ventral edge of the body. The author used “scute” term because it said to be thicker than what would be expected of scales and are ornamented. The scutes are ornamented with rows of small round tubercles and some have ridge running across the middle from edge to edge. There are six rows in total of the scutes that run along the fish body. While the scute are fairly visible albeit not completely, the fins are very poorly preserved. This condition applied to the dorsal, anal, and caudal fins.[1]
Contrast to other early syngnathiforms such as Gasterothamphosus and Eekaulostomus that come from marine deposits, Protosyngnathus are believed to be inhabitant of freshwater environment. Its habitat has been reconstructed as fairly large, stable lake, possibly with anoxic lake. Protosyngnathus are believed to spend its entire life in fresh water. The presence of this fish in Eocene freshwater deposit indicates that at least one lineage of syngnathiforms had invaded freshwaters fairly early in the history of the group[1]
Reference
[edit]- ^ a b c d Murray, Alison M. (2022-12-31). "Re-description and phylogenetic relationships of †Protosyngnathus sumatrensis (Teleostei: Syngnathoidei), a freshwater pipefish from the Eocene of Sumatra, Indonesia". Journal of Systematic Palaeontology. 20 (1): 1–16. doi:10.1080/14772019.2022.2113832. ISSN 1477-2019.