The Arkadelphia Marl, also called the Arkadelphia Formation, is a geologic formation in Arkansas in Clark, Nevada, and Hempstead counties. It preserves fossils dating back to the late Maastrichtian stage of the Cretaceous period.

Paleofauna

Bony fish

Bony fish reported from the Arkadelphia Formation
GenusSpeciesPresenceMaterialNotesImages
Albulidae indet.IndeterminateCabot, Arkansas.4 small, eroded otoliths.A bonefish.
AmpheristusA. cf. A. americanusCabot, Arkansas.6 otoliths.An ophidiiform.
AnguillaA.? chickasawaeCabot, Arkansas.6 otoliths.An eel.
ApateodusA. crenellatus?Cabot, Arkansas.3 otoliths.An aulopiform.
AriusA.? subtilisCabot, Arkansas.A well-preserved otolith (DMNH 2021-09-11).A catfish.
Clupeiformes? indeterminateIndeterminateCabot, Arkansas.An eroded, broken otolith (DMNH 2021-09-10).A clupeiform.
EchiophisE. aff. E. semisphaeroidesCabot, Arkansas.11 otoliths.An eel.
ElopothrissusE. sp.Cabot, Arkansas.One otolith (DMNH 2021-09-03).A bonefish.
ElopsE. sp.Cabot, Arkansas.A small, broken otolith (DMNH 2021-09-01).A ladyfish.
EutawichthysE. maastrichtiensisCabot, Arkansas.21 otoliths.A beryciform.
E. cf. E. stringeriCabot, Arkansas.48 otoliths.A beryciform.
E. zidekiCabot, Arkansas.287 otoliths.A beryciform.
Gadiformes indeterminateIndeterminateCabot, Arkansas.11 very small or broken otoliths.A gadiform.
GenartinaG. sp. 1Cabot, Arkansas.One otolith (DMNH 2021-09-04).
KokenichthysK. navisCabot, Arkansas.2 eroded otoliths.An osteoglossiform.
Lapillus type 1IndeterminateCabot, Arkansas.A small, slightly eroded otolith (DMNH 2021-09-31).An unidentified fish otolith.
MuraenanguillaM.? sp.Cabot, Arkansas.2 worn, broken otoliths.An eel.
OsmeroidesO. sp.Cabot, Arkansas.3 otoliths.
PalaeogadusP.? belliCabot, Arkansas.Multiple otoliths.A gadiform.
P. cf. P. weltoniCabot, Arkansas.A small, slightly eroded otolith (DMNH 2021-09-23).A gadiform.
ProtobythitesP. brzobohatyiCabot, Arkansas.4 otoliths.An ophidiiform.
TippahaT. mythicaCabot, Arkansas.8 otoliths.A holocentriform.
VorishiaV. vulpesCabot, Arkansas.1,537 otoliths.A catfish.

Rays

Rays reported from the Arkadelphia Formation
GenusSpeciesPresenceMaterialNotesImages
DasyatisD. sp.Ouachita River northwest of Malvern, Arkansas.3 oral teeth (AMNH 20194-20196)A stingray.
IschyrhizaI. avonicolaOuachita River northwest of Malvern, Arkansas.8 teeth (AMNH 20164-20171).A sawskate.
I. miraOuachita River northwest of Malvern, Arkansas.3 oral teeth (AMNH 20172-20174).A sawskate.
PtychotrygonP. cf. P. vermiculataOuachita River northwest of Malvern, Arkansas.4 oral teeth (AMNH 20183-20186).A sawskate.
RajaR. farishiOuachita River northwest of Malvern, Arkansas.3 oral teeth (AMNH 20187-20189).A skate.
RhinobatosR. casieriOuachita River northwest of Malvern, Arkansas.4 oral teeth (AMNH 20160-20163).A guitarfish.
RhombodusR. binkhorstiOuachita River northwest of Malvern, Arkansas.4 oral teeth (AMNH 20190-20193)A rajiforme.
SchizorhizaS. cf. S. stromeriOuachita River northwest of Malvern, Arkansas.5 rostral teeth (AMNH 20178-20182).A sawskate.
SclerorhynchusS. sp.Ouachita River northwest of Malvern, Arkansas.3 rostral teeth (AMNH 20175-20177).A sawskate.

Sharks

Sharks reported from the Arkadelphia Formation
GenusSpeciesPresenceMaterialNotesImages
CarchariasC. cf. C. holmdelensisOuachita River northwest of Malvern, Arkansas.5 anterior teeth (AMNH 20139-20143).A sand shark.
GaleorhinusG. girardotiOuachita River northwest of Malvern, Arkansas.4 lateral teeth (AMNH 20156-20159).A houndshark.
GinglymostomaG. lehneriOuachita River northwest of Malvern, Arkansas.4 lateral teeth (AMNH 20132-20135).A carpet shark.
OdontaspisO. aculeatusOuachita River northwest of Malvern, Arkansas.2 lateral teeth (AMNH 20137 & 20138).A sand shark.
PlicatoscylliumP. cf. P. derameeiOuachita River northwest of Malvern, Arkansas.Lateroanterior tooth (AMNH 20136).A carpet shark.
SerratolamnaS. serrataOuachita River northwest of Malvern, Arkansas.6 teeth (AMNH 20144-20149).A mackerel shark.
SqualicoraxS. kaupiOuachita River northwest of Malvern, Arkansas.6 lateral teeth (AMNH 20150-10155).A mackerel shark.
SquatinaS. hasseiOuachita River northwest of Malvern, Arkansas.4 lateral teeth (AMNH 20128-20131).An angelshark.

See also

  • Various Contributors to the Paleobiology Database. .