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  • Macrosemius rostratus Agassiz 1844




    Kingdom: Animalia
    Phylum: Chordata Haeckel 1874
    Class: Actinopteri Cope 1871
    Order: Semionotiformes Arambourg and Bertin 1958
    Family: Macrosemiidae Thiollière 1858
    Genus: Macrosemius
    Species: Macrosemius rostratus
    Author Citation Agassiz 1844

    Geological Time Scale

    Eon: Phanerozoic
    Era: Mesozoic
    Period: Jurassic
    Sub Period: None
    Epoch: Late
    International Age: Tithonian


    Weissjura Group
    Altmühltal Formation


    Hybonoticeras hybonotum Zone
    Subplanites rueppelianus Subzone


    Acquired by: Purchase/Trade


    Length: 11 cm


    Obere Haardt Quarry
    Langenaltheim Village


    Taxonomy according to fossilworks.org.

    Diagnosis for the genus according to Bartram, 1977 (p. 140, excerpts): "Large, elongate macrosemiid fishes; skull roof free from ganoine; supratemporals  greatly reduced; cephalic division of main lateral line and supratemporal commisure exposed by fenestrae; vomers bearing a transverse row of stout pointed teeth and a pair of large blunt teeth; ventral parts of anterior three infraorbitals expanded and overlapping the maxilla; gape very small, the quadrate articulation lying in front of the orbit ... dorsal fin single, extending from the occiput to the base of caudal fin, with between 32 and 39 rays each bearing denticles, leading ray proceeded by two basal fulcra, fringing fulcra absent; region immediately on either side of dorsal fin devoid of scales; scales rhomboid, secondary transverse rows intervening between primary rows above the lateral line, scales below lateral line forming a pattern of rectangles."


    Line drawing from Bartram, 1977, p. 141.

    Identified by oilshale using Bartram, 1977. Macrosemius is easily recognized among the fishes of Solnhofen by the continuous dorsal fin.

    Agassiz, L. (1843): Recherches Sur Les Poissons Fossiles. Tome I (livr. 18). Imprimerie de Petitpierre, Neuchatel xxxii-188.

    Bartram, A. W. H. (1977): The Macrosemiidae, a Mesozoic family of holostean fishes. Bulletin of the British Museum (Natural History), Geology Series 29:137–234.

    Ebert, M., Lane, Jennifer A. & Kölbl-Ebert, Martina (2016): Palaeomacrosemius thiollieri, gen. et sp. nov., a new Macrosemiidae (Neopterygii) from the Upper Jurassic of the Solnhofen Archipelago (Germany) and Cerin (France), with a revision of the genus Macrosemius. Journal of Vertebrate Paleontology, DOI: 10.1080/02724634.2016.1196081.

    Macrosemius line drawing.JPG


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