PBDB Collection

Microlestes Quarry, Frome (Triassic of the United Kingdom)

Also known as Holwell

Where: England, United Kingdom (51.2° N, 2.4° W: paleocoordinates 35.7° N, 1.1° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Rhaetian (208.5 - 201.3 Ma)

• Rhaetian fissure infill, "Lower Rhaetic"

• bed-level stratigraphic resolution

Environment/lithology: fissure fill; lithified, green claystone and poorly lithified sandstone

• "The filling may be a peculiar greenish clay, or hard clay with pebbles, etc., or friable sand."

Size classes: mesofossils, microfossils

Collected by C. Moore, W. Kühne in 1860, 1939

Collection methods: bulk, peel or thin section, sieve,

• Moore collection at Bath Geology Museum.

Primary reference: R. Owen. 1871. Monograph of the fossil Mammalia of the Mesozoic formations. 24(110):vi-115 [R. Butler/R. Butler/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 120898: authorized by Matthew Clapham, entered by Matthew Clapham on 23.11.2011, edited by Roger Benson, Richard Butler, Priscilla Vazquez, Matthew Carrano, Emma Dunne and Philip Mannion

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Reptilia
Saurischia -	Thecodontosaurus sp.⁶ Thecodontosaurus sp.⁶ Riley and Stutchbury 1836 sauropodomorph
Phytosauria -	Palaeosaurus sp.⁶ Palaeosaurus sp.⁶ Riley and Stutchbury 1836 archosaur
Diapsida - Trilophosauridae	Variodens sp.¹¹, Variodens inopinatus¹⁰ Variodens sp.¹¹ Robinson 1957 archosauromorph Variodens inopinatus¹⁰ Robinson 1957 archosauromorph Referred material: Specimen BATGM CD4, an anterior mid-region fragment of a left dentary
Placodontia -	Placodontia indet.⁶ Placodontia indet.⁶ placodont
Choristodera -	Pachystropheus sp.⁹ Pachystropheus sp.⁹ von Huene 1935 choristodere
Rhynchocephalia -	Gephyrosaurus sp.¹¹, Gephyrosaurus evansae n. sp.¹⁰ Gephyrosaurus sp.¹¹ Evans 1980 rhynchocephalian Gephyrosaurus evansae n. sp.¹⁰ Whiteside and Duffin 2017 rhynchocephalian Holotype: Specimen BATGM CD1: anterior and mid region of the lower part of a right maxilla displaying emplacements for 24 pleurodont teeth
Parareptilia - Procolophonidae	Procolophonidae indet.¹¹ Procolophonidae indet.¹¹ Lydekker 1889 parareptile
Osteichthyes
Morganucodonta - Morganucodontidae	"Eozostrodon parvus n. gen. n. sp." = Eozostrodon parvus⁷, "Eozostrodon problematicus n. sp." = Eozostrodon parvus⁷ "Eozostrodon parvus n. gen. n. sp." = Eozostrodon parvus⁷ Parrington 1941 mammaliaform Holwell IX "Eozostrodon problematicus n. sp." = Eozostrodon parvus⁷ Parrington 1941 mammaliaform Holwell XIII
Therapsida - Haramiyidae	"Microlestes moorei n. sp." = Thomasia moorei, "Microcleptes fissurae n. sp." = Thomasia antiqua⁸, "Thomasia anglica n. sp." = Thomasia antiqua⁸, "Microcleptes sp." = Thomasia⁸ "Microlestes moorei n. sp." = Thomasia moorei Owen 1871 mammaliaform Bath Museum M211-M217, M222; YPM 13622A (molars) "Microcleptes fissurae n. sp." = Thomasia antiqua⁸ Plieninger 1847 mammaliaform BMNH M2401A-C (molars) "Thomasia anglica n. sp." = Thomasia antiqua⁸ Plieninger 1847 mammaliaform Bath Museum M219, M221; YPM 13622b (molars) "Microcleptes sp." = Thomasia⁸ Poche 1908 mammaliaform Bath Museum M218 (a canine/incisor), M220 (four canines/incisors)
Dipnoi - Ceratodontidae	Ceratodus sp.⁹ Ceratodus sp.⁹ Agassiz 1838 lungfish
Palaeonisciformes - Palaeoniscidae	"Gyrolepis alberti" = Gyrolepis albertii⁶ "Gyrolepis alberti" = Gyrolepis albertii⁶ Agassiz 1834
Palaeonisciformes - Birgeriidae	Birgeria sp.⁶, "Saurichthys acuminatus" = Birgeria acuminata⁶ Birgeria sp.⁶ Stensiö 1919 "Saurichthys acuminatus" = Birgeria acuminata⁶ Agassiz 1843
Actinopteri
Perleidiformes - Colobodontidae	Colobodus sp.⁶ Colobodus sp.⁶ Agassiz 1843
Semionotiformes - Semionotidae	Sargodon tomicus⁶ Sargodon tomicus⁶ Plieninger 1847
Chondrichthyes
Chimaeriformes - Myriacanthidae	Agkistracanthus mitgelensis³ Agkistracanthus mitgelensis³ Duffin and Furrer 1981 chimaera M186, a-e
Synechodontiformes -	"Hybodus minor" = Rhomphaiodon minor⁶ "Hybodus minor" = Rhomphaiodon minor⁶ Agassiz 1837 elasmobranch
Synechodontiformes - Palaeospinacidae	Nemacanthus sp.⁹, "Palaeospinax rhaeticus" = Synechodus rhaeticus¹ Nemacanthus sp.⁹ Agassiz 1836 elasmobranch "Palaeospinax rhaeticus" = Synechodus rhaeticus¹ Duffin 1982 elasmobranch CD19-20, M181a-c
Euselachii -	"Vallisia coppi" = Vallisodus coppi², "Polyacrodus holwellensis n. sp." = Duffinselache holwellensis⁵ "Vallisia coppi" = Vallisodus coppi² Duffin 1982 elasmobranch "Polyacrodus holwellensis n. sp." = Duffinselache holwellensis⁵ Duffin 1998 elasmobranch CD16, M181
Lamniformes - Cetorhinidae	Pseudocetorhinus pickfordi n. gen. n. sp.⁴ Pseudocetorhinus pickfordi n. gen. n. sp.⁴ Duffin 1998 basking shark CD23, 1997/1-11
Hybodontiformes -	Lissodus sp.⁹, "Acrodus minimus" = Lissodus minimus⁶ Lissodus sp.⁹ Brough 1935 elasmobranch "Acrodus minimus" = Lissodus minimus⁶ Agassiz 1839 elasmobranch
Hybodontiformes - Acrodontidae	Palaeobates reticulatus n. sp.⁵ Palaeobates reticulatus n. sp.⁵ Duffin 1998 elasmobranch CD18, M176
Hybodontiformes - Polyacrodontidae	"Hybodus cloacinus" = Polyacrodus cloacinus⁶ "Hybodus cloacinus" = Polyacrodus cloacinus⁶ Quenstedt 1858 elasmobranch
Hybodontiformes - Pseudodalatiidae	Pseudodalatias sp.⁹ Pseudodalatias sp.⁹ Reif 1978 elasmobranch
Penegephyrosaurus curtiscoppi
-	Penegephyrosaurus curtiscoppi n. sp.¹⁰ Penegephyrosaurus curtiscoppi n. sp.¹⁰ Whiteside and Duffin 2017 Holotype: BATGM C193: a part of a left dentary with emplacements for five teeth

¹Duffin 1982; ²Duffin 1982; ³Duffin 1994; ⁴Duffin 1998; ⁵Duffin 1998; ⁶Macfadyen 1970; ⁷Parrington 1941; ⁸Simpson 1928; ⁹Storrs 1994; ¹⁰Whiteside and Duffin 2017; ¹¹Whiteside et al. 2016