PBDB Collection

IGM 2940, N. of Temalac (Cretaceous of Mexico)

Where: Guerrero, Mexico (18.2° N, 98.9° W: paleocoordinates 24.2° N, 80.8° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Mexcala Formation, Late/Upper Maastrichtian (70.6 - 66.0 Ma)

• Was scored as Early Maastrichtian. However: “An upper Maastrichtian age for the beds that contain the specimens here described was inferred based upon the presence of the following index species of foraminifera: Gansserina gansseri (Bolli). Rosita fomicata (Plummer), Globotruncana ventricosa (White). G. linn eiana (d'Orbigny), Rugoglobigerina rugosa (Plummer), Hedbergella monmouthensis (Olsson). and Heterohelix globulosa (Ehrenberg). These species were identified by Brian Huber (personal communication)."

• group of beds-level stratigraphic resolution

Environment/lithology: marine; brown marl and fine-grained, calcareous sandstone

• The assemblage of invertebrate fauna is interpreted as shallow marine, possibly associated with a deltaic system. However, the abundance of planktic foraminifera and the broken delicate structures of the gastropod shells (aperture and spines), suggest that the material was reworked into a deeper environment, contemporaneously with the deposition of the planktic foraminifera.

Size classes: macrofossils, mesofossils

Collection methods: Repository: IGM (Museo Paleontologia del Instituto Geologia, Universidad Nacional Autonoma de Mexico)

Primary reference: M. C. Perrilliat, F.J. Vega, and R. Corona. 2000. Early Maastrictian mollusca from the Mexcala formation of the state of Guerro, southern Mexico. Journal of Paleontology 74(1):7-24 [M. Kosnik/M. Kosnik/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 7463: authorized by Matt Kosnik, entered by Matt Kosnik on 18.07.2000, edited by Pete Wagner and Brooke Santos

Creative Commons license: CC BY (attribution)

Taxonomic list

• The fauna is now known to include planktic and benthic foraminifera; solitary, shallow-water hermatypic corals; gastropods; bivalves, scaphopods; reworked ammonoids and nautiloids; crabs; spatangoid echinoids; marine vertebrate remains; and palynomorphs. Previous paleontologic work on this fauna includes a species of retroplumid crab (Vega & Feldmann, 1992), as we ll as preliminary reports on the mollusks (Salccda ct al., 1995; Vega & Perrilliat, 1995; Perrilliat & Vega, 1996); and echinoids (Sanchez-Rodriguez et al., 1995; Sanchez-Rodriguez, 1997).

Show authors, comments, and common names

Bivalvia
Mytilida - Crenellidae	Crenella serica Crenella serica Conrad 1860 clam Crenella serica Conrad
Pectinida - Pectinoidae	Camptonectes sp. Camptonectes sp. Meek 1864 scallop Camptonectes sp.
Nuculida - Nuculidae	Nucula ciboloensis Nucula ciboloensis nut clam Nucula ciboloensis Stephenson
Gastropoda
Neogastropoda -	Mexfusus rotundicostatus n. gen. n. sp.² Mexfusus rotundicostatus n. gen. n. sp.² Vermeij et al. 2004 snail
Neogastropoda - Fasciolariidae	Drilluta gloriae Drilluta gloriae snail Drilluta gloriae Perrilliat et al.
Sorbeoconcha - Xenophoridae	Acanthoxenophora sinuosa n. gen. n. sp.¹ Acanthoxenophora sinuosa n. gen. n. sp.¹ Perrilliat and Vega 2001 carrier shell
Foraminifera
Globigerinaceae - Heterohelicidae	Heterohelix globulosa¹ Heterohelix globulosa¹ Ehrenberg 1840
Globigerinaceae - Globotruncanidae	Gansserina gansseri¹, Rosita fornicata¹, Rugoglobigerina rugosa¹, Globotruncana ventricosa¹, Globotruncana linneiana¹ Gansserina gansseri¹ Bolli 1951 Rosita fornicata¹ Rugoglobigerina rugosa¹ Plummer 1927 Globotruncana ventricosa¹ Globotruncana linneiana¹ d'Orbigny 1839
Globigerinina - Hedbergellidae	Hedbergella monmouthensis¹ Hedbergella monmouthensis¹ Olsson 1960

¹Perrilliat and Vega 2001; ²Vermeij et al. 2004