This paper provides the first geological and paleontological data of Yosobé and La Lobera, two Late Jurassic vertebrate localities; both localities are part of the marine

This paper provides the first geological and paleontological data on two Mexican Paleocene fossil localities, the División del Norte and the Belisario Domínguez quarries, recently discovered near Palenque, State of Chiapas. Both are part of the marine outcrops previously known as the Tenejapa (toward the West) and the Lacandón formations (toward the East and in Guatemala). Since the limits of these formations remain unclear in the Palenque area, the geological association of these localities is referred to as the Paleocene Tenejapa-Lacandón Unit. The fossil fishes are particularly abundant and well preserved in these sites; they represent taxa previously known from Eocene localities around the world, whose strata were deposited under continental and marine conditions. This new assemblage is peculiar because it includes potential new species of Pycnodontiformes, Osteoglossiformes, Anguillifromes, Clupeiformes, and "serranids" that might expand their temporal and paleogeografical distribution worldwide and therefore become important elements to understand the evolution of these groups. These 63 my fish localities are the closest, temporally and geographically, sites to the Chicxulub Crater, a crater intimately associated to the Mass Extinction Event at the Cretaceous-Paleogene boundary (K/P). These newly localities represent an important paleontological scenario that will contribute to achieve a better understanding of the marine vertebrate communities throughout this important geological event.

Paraclupea seilacheri sp. nov. is described in this paper. This ellimmichthyiform fish from the Albian deposits of the Tlayúa quarry, near Tepexi de Rodríguez, Puebla, central Mexico, shows the diagnostic characters of the superorder Clupeomorpha (the otophysic connection, commissure of the supratemporal sensory canal passing through parietals, and the abdominal scute series), order Ellimmichthyiformes (parietals in contact to each other along the midline of the skull; a beryciform foramen in the anterior ceratohyal; three epurals in the caudal skeleton; and a series of predorsal scutes), and family Paraclupeidae (predorsal scutes with increasing sizes  in anterioposterior order  and  postpelvic abdominal scutes with  a strong ventral spine). Additionally, the characters of this new Mexican fish are distinctive and support the creation of a new species of the genus Paraclupea, these include a diamond shaped body moderately high; 18 predorsal scutes strongly ornamented with radiating ridges; most posterior predorsal scutes are subrectangular, wider than long; the abdominal scutes are spatula-like; the dorsal process of posttemporal bone is hypertrophied; and the second uroneural is short and distally reaches the end of the first uroneural. The present finding introduces the second species of the genus Paraclupea; a significative increase in the geographical distribution of this genus in the Northern Hemisphere, from eastern China to the southern North America; and the third North American Cretaceous paraclupeid after Tycheroichthys dunveganensis and Scutatoclupea applegatei.

A new fossil herring species is named in this work as Armigatus carrenoae, based on specimens from the marine Albian deposits of the Tlayúa Formation, near Tepexi de Rodríguez, Puebla, Central Mexico. The new species shows the most distinctive feature of the superorder Clupeomorpha, the abdominal scute series, as well as the order Ellimmichthyiformes, the posteriormost predorsal scutes laterally expanded, the mesoparietal condition of the skull, and the presence of the beryciform foramen in the anterior ceratohyal. Also, this species shares the diagnostic features of the genus Armigatus, the parasphenoid has an osteoglossid-like tooth patch and the predorsal scutes series is incomplete. Additionally, in this species, the posteriormost predorsal scutes exhibit a posterior spine, a character not observed before in Armigatus. This discovery is highly significant because it represents the oldest member of Armigatus, as well as the first record of the genus in America and reveals its unsuspected wide distribution during the late Early to Late Cretaceous throughout the Tethys Sea deposits, from America to the Middle East.

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