Gavinia, Sangiorgioichthys, Parasemionotus, Luganoia, Seminonotus bergeri

Gavinia syntrips (Long 1999, NMC P160710 skull, NMV P160709 tail, Middle Devonian) is basal to the coelacanths (Actinistia). It has a heterocercal tail, a long dentary and is missing its middle portion.

Sangiorgioichthys sui (Tintori and Lombardo 2007, López-Arbarello et al 2011, Anisian, Triassic) is the basalmost ray-fin fish (Actinopterygii) in the LRT. Other species are known from Europe. Traditionally considered a close relative of Parasemionotus, it is, but closer to Robustichthys. This split is documented in the Triassic, but must have happened in the Middle Silurian. Note the small size of the pectoral and pelvic fins. Teeth are short, narrow and sharp.

Luganoia fortuna (Brough 1939, Bürgin 1992, Xu 2020; Middle Triassic; IVPP V 25693; 6cm) is a phylogenetic miniaturized coelacanth and Saurichthys ancestor arising from Robustichthys and phylogenetically miniaturized.

Parasemionotus sp. (Lehman 1952; Early Triassic. 7.5cm) is found in nodules from Madagascar. Originally allied with Albertonia and Amia, here Parasemionotus nests basal to Actinista alongside another tiny taxon, Luganoia. Note the transitional tail shape.

Semionotus bergeri (Agassiz 1843; Olson and McCune 1991; Late Triassic) also has thick scales and small fins. Here the maxilla is even smaller.

Semionotus elegans is more closely related to the gars like Lepisosteus.

Agassiz L 1839. Recherches sur les poissons fossiles II. Petitpierre, Neuchâtel.

Brough J 1939. The Triassic fishes of Besano, Lombardy. London: British Museum (Natural History). 1–117.

Bürgin T 1992. Basal ray-finned fishes (Osteichthyes; Actinopterygii) from the Middle Triassic of Monte San Giorgio (Canton Tessin, Switzerland). Schweiz Paläont Abh, 114: 1–164.

Cavin L, Furrer H and Obrist C 2013. New coelacanth material from the Middle Triassic of eastern Switzerland, and comments on the taxic diversity of actinistans. Swiss J Geosci 106:161–177.

Cavin L et al (4 co-authors) 2017. Heterochronic evolution explains novel body shape in a Triassic coelacanth from Switzerland. Nature.com Scientific Reports 7: 13695 DOI:10.1038/s41598-017-13796-0

Fang G and Wu F 2022. The predatory fish Saurichthys reflects a complex underwater ecosystem of the Late Triassic Junggar Basin, Xinjiang, China. Historical Biology https://doi.org/10.1080/08912963.2022.2098023

Friedman M and Coates MI 2006. A newly recognized fossil coelcanth highlights the early morphological diversification of the clade. Proceedings B Biological Science 273(1583):245–250. online

Geng B-H, Zhu M and Jin F 2009. A revision and phylogenetic analysis of Guizhoucoelacanthus (Sarcopterygii, Actinistia) from the Triassic of China. Vertebratea PalAsiatica 7:165–177.

Giles S, Friedma M and Brazeau MD 2015. Osteichthyan-like cranial conditions in an Early Devonian stem gnathostome. Nature, 520 (7545): 82–85.

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Lehman J-P 1952. Etude complementaire des Poissons de l'Eotrias de Madagascar. K. Svenska Vetenskapsakad. Handl., ser. 4, bd. 2, no. 6:1–201

Liu G B, Yin G Z, Luo Y M et al 2006. Preliminary examination of fish fossils from Upper Triassic Wayao Member of Falang Formation in Guanling of Guizhou. Acta Palaeont Sin 45(1): 1-20.

Long JA 1999. A new genus of fossil coelacanth (Osteichthyes: Coelacanthiformes) from the Middle Devonian of southeastern Australia. Records of the Western Australian Museum Supplement 57:37–53.

López-Arbarello et al (7 co-authors) 2011. New species of Sangiorgioichthys Tintori and Lombardo, 2007 (Neopterygii, Semionotiformes) from the Anisian of Luoping (Yunnan Province, South China). Zoottaxa 2749:25–39.

Melton WG 1969. A new dorypterid fish from central Montana. Northwest Science 43:196-206.

Münster GG 1834. Mitteilungen an Professor Bronn gerichtet.– Neues Jahrbuch fr Mineralogie, Geognosie, Geologie und Petrefakten-Kunde 1834: 538–542.

Olsen PE and McCune AR 1991. Morphology of the Semionotus elegans species group from the Early Jurassic part of the Newark Supergroup of eastern North America with comments on the Family Semionotidae (Neopterygii). Journal of Vertebrate Paleontology: 11(3):272.

Tintori A and Lombardo C 2007. A new early Semionotidae (Semionotiformes, Actinopterygii) from the Upper Ladinian of the Monte San Giorgio area (Southern Switzerland and Northern Italy). Rivista Italiana di Paleontologia e Stratigrafia, 113, 369–381.

Xu G-H 2020. A new species of Luganoia (Luganoiidae, Neopterygii) from the Middle Triassic Xingyi Biota, Guizhou, China. Vertebrata PalAsiatica 58(4):267–282.

wiki/Gavinia
wiki/Sangiorgioichthys
wiki/Luganoia
wiki/Semionotus
wiki/Parasemionotus