This page covers the stem group of the neopterygian fishes (clade Neopterygii, Superclass Actinopterygii). The clade contains over 30,000 species in 4,914 genera and 509 families (Encyclopedia of Life, eol.org/pages/2775792).
The stem-Neopterygii are quite well represented in the fossil record. Their phylogenetic relationships are shown in the time tree below:
The stem-Neopterygii are quite well represented in the fossil record. Their phylogenetic relationships are shown in the time tree below:
Figure 1. Time tree of the stem-Neopterygii
The oldest known member of the stem-Neopterygii is Discoserra pectinodon, described from the Early Carboniferous (Serpukhovian) Bear Gulch Limestone member of the Heath Formation at a location south of Becket, Fergus County, Montana (Lund, 2000; Latimer and Giles, 2018). This species is illustrated below, together with other members of the stem group for which public-domain images are available (for a larger view, click on image):
Names in red indicate that the fossil is younger than the oldest known crown-group fossil.
Figure 2. Images of stem-group Neopterygii
The images shown above are numbered in order from most basal towards the crown group, but no obvious trends can be seen.
The stem-to-crown transition of the Neopterygii lasted at least 71 million years, from the Early Carboniferous to the Early Triassic (Figure 1).
The stem-to-crown transition of the Neopterygii lasted at least 71 million years, from the Early Carboniferous to the Early Triassic (Figure 1).
References
Latimer, A. E., & Giles, S. (2018). A giant dapediid from the Late Triassic of Switzerland and insights into neopterygian phylogeny. Royal Society open science, 5(8), 180497.
López-Arbarello, A., & Sferco, E. (2018). Neopterygian phylogeny: the merger assay. Royal Society Open Science, 5(3), 172337.
Lund, R. (2000). The new actinopterygian order Guildayichthyiformes from the Lower Carboniferous of Montana (USA). Geodiversitas, 22(2).
López-Arbarello, A., & Sferco, E. (2018). Neopterygian phylogeny: the merger assay. Royal Society Open Science, 5(3), 172337.
Lund, R. (2000). The new actinopterygian order Guildayichthyiformes from the Lower Carboniferous of Montana (USA). Geodiversitas, 22(2).
Image credits - Stem-Neopterygii
- Figure 2 (Ebenaqua ritchei, fossil): Ghedoghedo, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- Figure 2 (Ebenaqua ritchei, life restoration): Apokryltaros, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- Figure 2 (Bobosatrania canadensis): DiBgd, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- Figure 2 (Discoserra pectinodon): Gyik Toma (Tommy the paleobear) from Romania, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
- Figure 2 (Brembodus ridens): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
- Figure 2 (Gibbodon cenensis): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
- Figure 2 (Mesturus verrucosus): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
- Figure 2 (Arduafrons prominoris): Ghedoghedo, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- Figure 2 (Peltopleurus lissocephalus): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
- Figure 2 (Dipteronotus ornatus): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons