Marcopoloichthys

{{Short description|Extinct genus of fishes}}

{{Automatic taxobox

| fossil_range = {{fossil range|Anisian|Norian|Middle Triassic–Late Triassic}}

| image = Marcopoloichthys furreri lateral view 2.jpg

| image_caption = Specimens of M. furreri

| parent_authority = Tintori et al, 2007

| display_parents = 2

| taxon = Marcopoloichthys

| authority = Tintori, Sun, Lombardo, Jiang, Sun, Rusconi & Hao, 2007

| subdivision_ranks = Species

| subdivision = * M. ani Tintori et al, 2007

• M. andreetti Tintori et al, 2007
• M. faccii (Gortani, 1907)
• M. furreri Arratia, 2022
• M. mirigioliensis Arratia et al, 2024

}}

Marcopoloichthys is an extinct genus of marine teleosteomorph ray-finned fish known from the Middle and Late Triassic of the former Tethys Ocean (Italy, Switzerland, and China). It is the only genus in the family Marcopoloichthyidae. It was originally described based on specimens from both Italy and China, hence the name Marcopoloichthys, which references the medieval Venetian merchant Marco Polo, who traveled from Italy to China.{{Cite journal |last1=Tintori |first1=Andrea |last2=Sun |first2=Zuo-Yu |last3=Lombardo |first3=Cristina |last4=Jiang |first4=Da-Yong |last5=Sun |first5=Yuan-Lin |last6=Rusconi |first6=Marco |last7=Hao |first7=Wei-cheng |date=2007 |title=NEW SPECIALIZED BASAL NEOPTERYGIANS (ACTINOPTERYGII) FROM TRIASSIC OF THE TETHYS REALM |url=https://www.researchgate.net/publication/284619969 |journal=Geol. Insubr |volume=10 |issue=2 |via=ResearchGate}}{{Cite web |title=PBDB |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=285724 |access-date=2024-01-04 |website=paleobiodb.org}}

Five species are known:

• M. ani Tintori et al., 2007 – Anisian of Yunnan, China. (type species)
• M. andreetti Tintori et al., 2007 – Ladinian of Lombardy, Italy.
• M. faccii (Gortani, 1907) – Carnian of Friuli-Venezia Giulia, Italy (initially described as Pholidophorus faccii)
• M. furreri Arratia, 2022 – Ladinian of Grisons, Switzerland{{Cite journal |last=Arratia |first=Gloria |date=2022-05-07 |title=The outstanding suction-feeder Marcopoloichthys furreri new species (Actinopterygii) from the Middle Triassic Tethys Realm of Europe and its implications for early evolution of neopterygian fishes |url=https://fr.pensoft.net/article/85621/ |journal=Fossil Record |language=en |volume=25 |issue=2 |pages=231–261 |doi=10.3897/fr.25.85621 |doi-access=free |issn=2193-0074}}
• M. mirigioliensis Arratia et al., 2024 – late Anisian of the Besano Formation (Monte San Giorgio, Ticino, Switzerland){{Cite journal |last1=Arratia |first1=Gloria |last2=Bürgin |first2=Toni |last3=Furrer |first3=Heinz |date=2024-06-14 |title=A new suction feeder and miniature teleosteomorph, Marcopoloichthys mirigioliensis, from the lower Besano Formation (late Anisian) of Monte San Giorgio |journal=Swiss Journal of Palaeontology |volume=143 |issue=1 |pages=25 |doi=10.1186/s13358-024-00318-5 |doi-access=free |bibcode=2024SwJP..143...25A |issn=1664-2384}}

The youngest Marcopoloichthys fossils are of an undescribed species from the Norian of Friuli, Italy.File:Marcopoloichthys furreri skull reconstructions.jpg

Marcopoloichthys was a small, scaleless fish with highly specialized, protractile jaws for suction feeding, and a combination of primitive and advanced morphological characters that make it difficult to phylogenetically place. Initially described as an indeterminate basal neopterygian, more recent studies have found it to be a stem-teleost. It somewhat resembles another early teleostomorph, Prohalecites.