Silurolepis

Silurolepis platydorsalis is an extinct species of Silurian-aged "maxillate"[1] placoderm that has been described from (mostly) articulated remains. Although it has been known for several years, it was finally described by Zhang, et al., in 2010.[2] The earliest described placoderm is the yunnanolepid antiarch, Shimenolepis, from Llandovery Hunan. In contrast to S. platydorsalis, Shimenolepis is known only from distinctively ornamented thoracic armor plates that bear anatomic features unique to yunnanolepids.[3][4]

Silurolepis Temporal range: Ludlow
restoration
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†incertae sedis
Family:	†Silurolepidae Zhang et al., 2010
Genus:	†Silurolepis Zhang et al., 2010
Species:	†S. platydorsalis
Binomial name
†Silurolepis platydorsalis Zhang et al., 2010

S. platydorsalis was previously considered a basal antiarch, but a 2019 study instead recovers it as a maxillate placoderm most closely related to Qilinyu.[1]

S. platydorsalis is known from thoracic armor: as the specific name suggests, the dorsal side is very flat.[2]

References

1. You-an Zhu; Jing Lu; Min Zhu (2019). "Reappraisal of the Silurian placoderm Silurolepis and insights into the dermal neck joint evolution". Royal Society Open Science. 6 (9).
2. Zhang, Guo-Rui; Shi-Tao Wang; Jun-Qing Wang; Nian-Zhong Wang; Min Zhu (2010). "A basal antiarch (placoderm fish) from the Silurian of Qujing, Yunnan, China". Palaeoworld. 19 (1–2): 129–135. doi:10.1016/j.palwor.2009.11.006.
3. Burrow, Carol & Turner, Susan (September 1998). "A review of placoderm scales, and their significance in placoderm phylogeny". Journal of Vertebrate Paleontology. 19 (2): 204–219. doi:10.1080/02724634.1999.10011135.
4. Wang Junqing (1991). "The Antiarchi From Early Silurian Hunan" (PDF). Vertebrata PalAsiatica. 21 (3): 240–244. Archived from the original (PDF) on 2013-12-12.