Eospinus

{{Short description|Species of fish}}

{{Speciesbox

| name =

| image = Eospinus daniltshenkoi.jpg

| image_caption = Life restoration of E. daniltshenkoi

| fossil_range = {{fossil range|56|55|Earliest Ypresian}}

| grandparent_authority = Santini & Tyler, 2002{{cite journal|first1=Francesco|last1=Santini|first2=James C.|last2=Tyler|year=2003|title=A phylogeny of the families of fossil and extant tetraodontiform fishes (Acanthomorpha, Tetraodontiformes), Upper Cretaceous to Recent|journal=Zoological Journal of the Linnean Society|volume=139|issue=4 |pages=565–617|doi=10.1111/j.1096-3642.2003.00088.x|doi-access=free}}

| parent_authority = Tyler & Bannikov, 1992

| taxon = Eospinus daniltshenkoi

| authority = Tyler & Bannikov, 1992

}}

Eospinus ("dawn spine") is an extinct genus of bizarre marine tetraodontiform fish from the Eocene.{{Cite web |title=PBDB Taxon |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=36294 |access-date=2025-01-21 |website=paleobiodb.org}}{{Cite journal |last=Tyler |first=James C. |last2=Bannikov |first2=Alexandre F. |date=1992 |title=Remarkable New Genus of Tetraodontiform Fish with Features of Both Balistids and Ostraciids from the Eocene of Turkmenistan |url=https://doi.org/10.5479/si.00810266.72.1 |journal=Smithsonian Contributions to Paleobiology |issue=72 |pages=1–14 |doi=10.5479/si.00810266.72.1 |issn=0081-0266}} It is known from the earliest Ypresian-aged{{Cite journal |last1=Bannikov |first1=A. F. |last2=Erebakan |first2=I. G. |date=2023-10-01 |title=On the Evolution of Some Groups of Marine Bony Fishes in the Cenozoic of the Tethys and Paratethys |journal=Paleontological Journal |language=en |volume=57 |issue=5 |pages=475–490 |bibcode=2023PalJ...57..475B |doi=10.1134/S0031030123050015 |issn=1555-6174}} Danata Formation lagerstatten of Turkmenistan. The species name honors paleoichthyologist Pavel G. Daniltshenko (also Danilchenko), who described numerous fossil fish from Russia and neighboring countries.

Eospinus had a highly unusual appearance. It had four dorsal spines, three of which were on the anterior end of its dorsal side, and the first spine being placed between and below the eyes, almost like a long nose. It also had a pair of spines near the base of its caudal peduncle, and a spine in front of the anal fin.

In 2002, and confirmed again in 2003, Santini and Tyler erected the family Bolcabalistidae to contain both Eospinus and the genus Bolcabalistes from Monte Bolca as close relatives of both triggerfishes and boxfishes.Tyler, JAMES C., and F. R. A. N. C. E. S. C. O. Santini. "Review and reconstructions of the tetraodontiform fishes from the Eocene of Monte Bolca, Italy, with comments on related Tertiary taxa." Studi e ricerche sui giacimenti terziari di Bolca 9 (2002): 47-119. The similar Moclaybalistes of Ypresian Denmark was originally also placed in Bolcabalistidae, too, in 2002, but then move it into its own monotypic family of Moclaybalistidae.

Eospinus inhabited the northeastern Tethys Ocean. Its morphology suggests a slow-moving benthic lifestyle likely associated with reefs, as with many modern tetraodontiforms.