ELSEVIER Palaeogeography, Palaeoclimatology, Palaeoecology 142 (1998) 231–254 Paleobiological implications of Campanian coprolites Rube ´n A. Rodrı ´guez-de la Rosa a , Sergio R.S. Cevallos-Ferriz b,L , Alicia Silva-Pineda b a Facultad de Ciencias, U.N.A.M., Circuito Exterior, Ciudad Universitaria, Delegacio ´n Coyoaca ´n 04510 Me ´xico D.F., Mexico b Instituto de Geologı ´a, U.N.A.M., Circuito de la Investigacio ´n Cientı ´fica, Ciudad Universitaria, Delegacio ´n Coyoaca ´n, 04510 Me ´xico D.F., Mexico Received 4 September 1997; accepted 26 January 1998 Abstract Vertebrate coprolites (153 samples) in association with vertebrate and plant remains in the Upper Cretaceous (Campanian) sediments of the Cerro del Pueblo Formation, in southeastern Coahuila, Mexico, represent at least ten morphotypes, ranging from ca. 1 cm to 3 cm. At least one suggests a carnivore origin due to the presence of abundant bone fragments, but most of the coprolite morphotypes were produced by either omnivores or herbivores. Analysis of inclusions of the coprolites revealed plant remains, such as stems and isolated vascular elements, and papillate and non-papillate cuticles. Two seed types have been recognized within two coprolite morphotypes. The first one has lythraceous affinity, being comparable to members of a morphological complex within Nesaeeae. The second seed type, which shows adaptations for water dispersal, belongs to Ranunculaceae, and is described as Eocaltha zoophila gen. et sp. nov. Although Eocaltha evolved a mechanism for abiotic dispersal, the seeds were apparently occasionally ingested by a vertebrate. The presence of seeds of E. zoophila in a coprolite suggests that the organism that produced it was looking for a high-quality diet perhaps represented by the seeds, and served indirectly as a biotic seed dispersal agent. The combination of abiotic and biotic dispersal syndromes, plus the fact that the seeds appear to be scarified suggest a case of diffuse coevolution. Interactions, as herbivory, during the Cretaceous prompted biotic dispersal of angiosperm diaspores as revealed by the presence of seeds of E. zoophila.  1998 Elsevier Science B.V. All rights reserved. Keywords: Upper Cretaceous; coprolites; Coahuila, Mexico; plants; vertebrates 1. Introduction Several attempts have been made to understand aspects of ancient terrestrial ecosystems from the scope of plant–animal interactions (e.g. Scott, 1977; Scott and Taylor, 1983; Taylor and Scott, 1983; Zavada and Mentis, 1987; Edwards et al., 1995), but these were based mainly on evidence from L Corresponding author. Fax: 550 66 14; E-mail: scrscfpb@servidor.unam.mx the Paleozoic. Scott et al. (1992) reviewed plant– animal interactions for the Paleozoic and Mesozoic and plant–insect interactions were also discussed by Scott (1992). However, some authors have dealt with interactions between Mesozoic vertebrates and gym- nosperms (e.g. Weishampel, 1984; Chin and Gill, 1996), while few researchers have dealt directly with interactions involving angiosperms (e.g. Bakker, 1978; Coe et al., 1987; Wing and Tiffney, 1987a,b; Collinson and Hooker, 1991; Tiffney, 1992). Al- though dental morphology, stomach contents and co- 0031-0182/98/$19.00  1998 Elsevier Science B.V. All rights reserved. PII S0031-0182(98)00052-2