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Pachyrisma

Bivalvia - Megalodontida - Megalodontidae

Taxonomy
Pachyrisma was named by Morris and Lycett (1850) [Sepkoski's age data: J Bath Sepkoski's reference number: 1066]. It is not extant. Its type is Pachyrisma grande.

It was assigned to Hippuritoida by Sepkoski (2002); to Pachyrismatidae by Bouchet et al. (2010); and to Megalodontidae by Kiessling (2003), Ros-Franch et al. (2014).

Synonymy list
YearName and author
1850Pachyrisma Morris and Lycett
2002Pachyrisma Sepkoski
2003Pachyrisma Kiessling
2010Pachyrisma Bouchet et al.
2014Pachyrisma Ros-Franch et al.

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RankNameAuthor
kingdomAnimalia()
—Bilateria
—EubilateriaAx 1987
—Protostomia
—Spiralia
superphylumLophotrochozoa
phylumMollusca
classBivalvia
—Eubivalvia
subclassAutobranchia(Groblen 1894)
RankNameAuthor
infraclassHeteroconchia(Gray 1854)
—CardiomorphiFerussac 1822
—CardioniFerussac 1822
—CardiidiaFerussac 1822
—CardiataFerussac 1822
superorderCardiiformiiFerussac 1822
orderMegalodontidaStarobogatov 1992
superfamilyMegalodontoidea(Morris 1853)
familyMegalodontidaeMorris 1853
genusPachyrismaMorris and Lycett 1850

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

G. †Pachyrisma Morris and Lycett 1850
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†Durga trigonalis Böhm 1884
Subg. †Pachyrisma (Pachymegalodon) Gümbel 1862
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†Pachymegalodus nimassicus Krumbeck 1923
†Pachyrisma grande Morris and Lycett 1850
†Pachyrisma rimosum Münster 1841
†Pachyrisma rostratum Münster 1841
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Invalid names: Isocardia minuta Klipstein 1843 [synonym]
Diagnosis
No diagnoses are available
Measurements
No measurements are available
Composition: aragonitef
Locomotion: stationaryf
Life habit: semi-infaunalf
Diet: suspension feederf
Vision: blindf
Created: 2025-05-16 23:42:40
Modified: 2025-05-16 23:44:10
Source: f = family
Reference: Foote et al. 2024

Age range: base of the Pelsonian to the top of the Early/Lower Tithonian or 244.24000 to 145.06000 Ma

Collections (24 total)


Time interval Ma Country or state Original ID and collection number
Anisian246.7 - 241.464Austria (Innsbruck) Megalodon rimosus (202274)
Anisian246.7 - 241.464Hungary (Bakony) Megalodus rimosus (203264)
Middle Triassic246.7 - 237.0Austria (Innsbruck) Megalodon rimosus (202279)
Bithynian - Pelsonian244.99 - 243.33Bulgaria Megalodon rimosus (44917)
Pelsonian - Tuvalian244.24 - 227.3Türkiye (Anatolia) Megalodon rimosum (204511 204518)
Longobardian239.48 - 237.0Italy (Trentino) Gonodon rostratus (44953)
Julian237.0 - 233.6Italy Gonodon rostratus, Megalodon rimosus, Megalodon rostratus, Megalodon minutus (144634) Isocardia rimosa, Isocardia rostrata (137429) Megalodon rimosus (34692 69661 69684) Megalodon rostratus (69688)
Hettangian - Sinemurian201.4 - 192.9Tajikistan P. chamaeformis (67013)
Pliensbachian192.9 - 184.2Indonesia (Timor) Pachymegalodus timorensis, Pachymegalodus nimassicus (205685 205686)
Pliensbachian192.9 - 184.2Oman Durga sp. (68356)
Pliensbachian192.9 - 184.2Slovenia P. chamaeforme (68358)
Late/Upper Pliensbachian - Early/Lower Toarcian192.9 - 182.9Morocco P. sp. (21261)
Pliensbachian - Early/Lower Toarcian192.9 - 182.9Italy P. sp. (42473)
Late/Upper Oxfordian157.9 - 154.8Germany P. cornuta (60387)
Late/Upper Kimmeridgian152.21 - 149.2Germany Pachyrismella latum (211294)
Early/Lower Tithonian149.2 - 145.06Germany (Bavaria) P. latum (57791) P. sp. (57157)