Marcopoloichthyidae Tintori et al., 2007

Arratia, Gloria, 2022, 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, Fossil Record 25 (2), pp. 231-261 : 231

Family Marcopoloichthyidae Tintori et al., 2007

Emended diagnosis.

The family diagnosis is based on a unique combination of characters (uniquely derived features among teleosteomorphs are identified with an asterisk [*]): Small fishes about 55 mm maximum length, with naked body, and highly modified protractile upper and lower jaws giving the anterior part of the head a characteristic profile [*]. The body shape is torpedo-like, with a head about 50% deeper than the caudal peduncle [*]. T-shaped mesethmoid with strong lateral processes. Two pairs of nasal bones [*]. Absence of supramaxillae [*]. Absence of dentition [*]. Preopercle L-shaped. Interopercle small triangle-like. Vertebral column with persistent notochord in older forms; chordacentral vertebral column in younger. Vertebral caudal region diplospondylous, with small interdorsal and interventral elements. Ossified ribs absent. Short, stout epineural processes associated to the abdominal neural arches. Large and curved pelvic plates. First dorsal fin proximal radial enlarged and plate-like, resulting from fusion of three or more radials and supporting four or more dorsal rays [*]. Enlarged last dorsal proximal radial supporting several dorsal rays [*]. First anal fin proximal radial basally expanded and very elongate and dorso-anteriorly bent, acting as post-coelomic bone [*]. Last anal fin proximal radial highly modified, expanded, and plate-like, supporting three or more lepidothrichia [*]. No fringing fulcra associated with paired, dorsal, or anal fins. Homocercal caudal fin with both lobes deeply forked. Body lobe of the caudal fin completely reduced. Ural region with five or six broad and short hypurals. Diastema hypural absent or very narrow. Caudal fin with dorsal and ventral scutes; well-developed epaxial and hypaxial basal fulcra; short series of epaxial and hypaxial fringing fulcra reaching about half length of first and last principal rays. Accessory fulcra present in hypaxial caudal lobe. Procurrent rays only present in the hypaxial lobe of caudal fin. Eighteen to 21 principal caudal rays. A few large scales around urogenital opening [*].

Content.

One genus and four species known, Marcopoloichthys ani , M. andreetti , M. faccii , and M. furreri sp. nov.

Geographic distribution.

Eurasian distribution, including Southern China (Yunnan and Guizhou Provinces), Northern Italy (Lombardy and Friuli), and eastern Switzerland (Canton Graubünden). Another undescribed species is present in the Middle Triassic of southern Switzerland, in Monte San Giorgio, Canton Ticino; T. Bürgin, pers. comm., 2022.

Age.

From Anisian (Middle Triassic) to Norian (Late Triassic).