close
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Mar 21;5(3):172337.
doi: 10.1098/rsos.172337. eCollection 2018 Mar.

Neopterygian phylogeny: the merger assay

Adriana López-Arbarello  1 , Emilia Sferco  2
Affiliations

Neopterygian phylogeny: the merger assay

Adriana López-Arbarello et al. R Soc Open Sci. .

Abstract

The phylogenetic relationships of the recently described genus †Ticinolepis from the Middle Triassic of the Monte San Giorgio are explored through cladistic analyses of the so far largest morphological dataset for fossil actinopterygians, including representatives of the crown-neopterygian clades Halecomorphi, Ginglymodi and Teleostei, and merging the characters from previously published systematic studies together with newly proposed characters. †Ticinolepis is retrieved as the most basal Ginglymodi and our results support the monophyly of Teleostei and Holostei, as well as Halecomorphi and Ginglymodi within the latter clade. The patterns of relationships within these clades mostly agree with those of previous studies, although a few important differences require future research. According to our results, ionoscopiforms are not monophyletic, caturids are not amiiforms and leptolepids and luisiellids form a monophyletic clade. Our phylogenetic hypothesis confirms the rapid radiation of the holostean clades Halecomorphi and Ginglymodi during the Early and Middle Triassic and the radiation of pholidophoriform teleosts during the Late Triassic. Crown-group Halecomorphi have an enormous ghost lineage throughout half of the Mesozoic, but ginglymodians and teleosts show a second radiation during the Early Jurassic. The crown-groups of Halecomorphi, Ginglymodi and Teleostei originated within parallel events of radiation during the Late Jurassic.

Keywords: Actinopterygii; Holostei; Mesozoic; Neopterygii; phylogeny; systematics.

PubMed Disclaimer

Conflict of interest statement

We declare we have no competing interests.

Figures

Figure 1.
Figure 1.
Morphology of ganoid scales. (a) †Sangiorgioichthys sui, reconstruction based on GMPKU-P-1642; (b) †Siemensichthys macrocephalus reconstruction based on [60]: fig. 10B; (c) †Australosomus kochi reconstruction based on [45]: text-fig. 57C; (d) †Semionotus bergeri reconstruction based on NMC 15128a; (e) †Callipurbeckia minor reconstruction based on NHMUK PV P8047; (f) †Scheenstia mantelli reconstruction based on NHMUK PV 2397 and 4916; (g) Lepisosteus sp. reconstruction based on MB.f.18498; (h) †Dentilepisosteus laevis reconstruction based on MPSC 901 in [5]: fig. 109B. Black circle, dorsal peg for the peg-and-socket articulation of adjacent scales; black star, anterodorsal process and white star, anteroventral process, both for the longitudinal articulation of adjacent scales.
Figure 2.
Figure 2.
Extent of the dermal outgrowths of the intercalar bone. (a) small dermal component without extensive outgrowths in †Ichthyokentema purbeckensis, reconstruction based on [90]: fig. 2; (b) dermal outgrowths contacting the prootic in Amia calva, reconstruction based on AMNH 90970 SD in [23]: fig. 23B; (c) extensive outgrowths contacting the prootic and parasphenoid in †Ionoscopus cyprinoides, reconstruction based on NHMUK PV 37795a in [78]: fig. 1A. Intercalar bone painted in red, parasphenoid painted in green. Abbreviations: boc, basioccipital; dpt, dermopterotic; exo, exoccipital; pro, prootic; sph, sphenotic.
Figure 3.
Figure 3.
Bar chart representing the values of the angle between the main axis of the hyomandibular facet and the longitudinal axes of the orbital portion of the parasphenoid (horizontal axis) obtained for 26 studied taxa.
Figure 4.
Figure 4.
Lateral dermethmoids: (a) forming small nasal processes of the premaxilla, only partially surrounding the olfactory foramen, in †Ticinolepis longaeva, line drawing of the premaxilla of MCSN 8007; (b) forming large nasal processes of the premaxilla, enclosing the olfactory foramen, in Amia calva, reconstruction based on AMNH 90970 SD in [23]: fig. 42A; (c) forming toothed dermethmoids in †Siemensichthys macrocephalus, reconstruction based on [74]: fig. 145; (d) forming part of a compound mesethmoid with chondral and dermal components in †Tharsis dubius, reconstruction based on [74]: fig. 130a. Abbreviations: eco, ethmoidal commissure; fr, frontal bone; lde, lateral dermethmoid; le, lateral ethmoid; mes, mesethmoid; np, nasal process of the premaxilla; of, olfactory foramen; palt, foramen for terminal branch of palatine nerve; plp, postero-lateral process of lateral dermethmoid; rode, rostrodermethmoid.
Figure 5.
Figure 5.
Symplectic-quadrate complex in †Aspidorhynchus acutirostris. (a) Photograph and (b) line drawing of JME 1997.III.6. (c) Photograph and (d) line drawing of SNSB-BSPG 1964.XXIII.542. Abbreviations: q, quadrate; sy, symplectic. Scale bars, 1 mm.
Figure 6.
Figure 6.
Reconstruction of the skull in †Scheenstia zappi, modified from [121]. Abbreviations: a.io, anterior infraorbital bone; ag, angular bone; ao, antorbital bone; a.pl, anterior pit line; cl, cleithrum; d, dentary; dpt, dermopterotic bone; dsph, dermosphenotic bone; ex, extrascapular bone; fr, frontal bone; io, infraorbital bone; io.c, infraorbital sensory canal; iop, interoperculum; ju, jugal bone; la, lachrymal; m.c, mandibular sensory canal; m.pl, middle pit line; mx, maxilla; na, nasal bone; o.c, orbital sensory canal; oc.c, occipital sensory canal; op, operculum; pa, parietal bone; pcl, postcleithrum; pio, posterior infraorbital bone; pmx, premaxilla; pop, preoperculum; pop.c, preopercular sensory canal; ptt, post-temporal bone; scl, supracleithrum; sio, subinfraorbital bone; so.c, supraorbital sensory canal; so, supraorbital bone; sop, suboperculum; suo, suborbital bone; t.c, temporal sensory canal. Scale bar, 1 cm.
Figure 7.
Figure 7.
Caudal skeleton in †Tharsis dubius (SNSB-BSPG 1964.VIII.280). Detailed photograph showing the uroneurals (un) and ‘posterior uroneurals’ (p.un). Detailed photograph showing the broad neural spines, with a median groove (gr), on the upper right corner.
Figure 8.
Figure 8.
Strict consensus tree of 24 most parsimonious trees, equal weights analysis with constraints. Tree length = 2175 steps, consistency index = 0.268 and retention index = 0.678. Bremer indexes and bootstrap values larger than 50 are indicated with red and black numbers, respectively, at the corresponding nodes. Halecomorphi is highlighted in blue, Ginglymodi in green and Teleostei in orange.
Figure 9.
Figure 9.
Single most parsimonious trees of the analyses with implied weights with constraints. (a) Strong K-value of 3; (b) moderate down-weighting K-value of 8. Halecomorphi is highlighted in blue, Ginglymodi in green and Teleostei in orange. Bremer and bootstrap values for these trees are available in electronic supplementary material, file S3.
Figure 10.
Figure 10.
Preopercular process of the hyomandibula in (a), †Tharsis dubius, reconstruction based on [174]: pl. 12, fig. 7; (b) †Luisiella feruglioi, reconstruction based on [175]: fig. 7C. Abbreviations: op.pr, opercular process; pop.pro, preopercular process.
Figure 11.
Figure 11.
(Caption overleaf.)
Figure 12.
Figure 12.
Graphic representation of the number of nominal species from Early and Middle Triassic freshwater (orange) and brackish and marine (green) sediments. Data from Romano et al. ([174]: table S3) with the addition of the following recently described taxa: †Ticinolepis longaeva and †T. crassidens from the Ladinian of the Monte San Giorgio [37]; †Frodoichthys luopingensis and †Gimlichthys dawaziensis from the Anisian of Yunnan Province [41]; †Mailingichthys nimaiguensis from the Ladinian of Guizhou Province [208]; †Panxianichthys imparilis from the Anisian of Paxian biota [164]; †Robustichthys luopingensis from the Anisian of Luoping Biota [33]; †Habroichthys dolomiticus from the Anisian of Monte Prà della Vacca [209]; †Altisolepis sinensis from the middle–late Anisian of Luoping [210]; †Calaichthys tehul from the Anisian of Cuyo Basin [211]; †Venusichthys comptus from the Pelsonian–Anisian of Luoping [212]; †Wushaichthys exquisitus [69]; †Peltopleurus nitidus from the Anisian of Luoping biota [177]; †Plesiofuro mingshuica from the Olenekian of Gansu Province [69].
Figure 13.
Figure 13.
Provenance of the studied taxa highlighting the biases due to the much higher representation of the main Mesozoic Lagerstätte. Table including simplified references to the stratigraphic and geographical provenance of the taxa (left). Pie charts representing the proportions of taxa represented in our data matrix according to their provenance. (a) Triassic; (b) Jurassic; (c) Cretaceous.
See this image and copyright information in PMC

References

    1. Species by Family/Subfamily. 2016. See http://www.calacademy.org/scientists/projects/catalog-of-fishes (accessed 6 October 2016).
    1. Sallan LC. 2014. Major issues in the origins of ray-finned fish (Actinopterygii) biodiversity. Biol. Rev. 89, 950–971. (doi:10.1111/brv.12086) - DOI - PubMed
    1. Friedman M. 2015. The early evolution of ray-finned fishes. Palaeontology 58, 213–228. (doi:10.1111/pala.12150) - DOI
    1. Hurley IA, Lockridge Mueller R, Dunn KA, Schmidt EJ, Friedman M, Ho RK, Prince VE, Yang Z, Thomas MG, Coates MI. 2007. A new time-scale for ray-finned fish evolution. Proc. R. Soc. B 274, 489–498. (doi:10.1098/rspb.2006.3749) - DOI - PMC - PubMed
    1. Grande L. 2011. An empirical synthetic pattern study of gars (Lepisosteiformes) and closely related species, based mostly on skeletal anatomy: the resurrection of Holostei. Copeia 2011, 612–613.