Rodney M. Feldmann

Cenozoic High Latitude Heterochroneity of Southern Hemisphere Marine Faunas

Discovery of 11 genera, in five classes within the Mollusca, Echinodermata, and Arthropoda in upper Eocene rocks on Seymour Island, Antarctica, previously known only from Late Cenozoic in mid-latitudes, suggests that the high latitude region of the Southern Hemisphere acted as a center of origin and dispersal for a broad spectrum of taxa. Precursors to modern deep- and shallow-water mid-latitude forms evolved and flourished in the high latitudes until conditions in lower latitudes favored their dispersal. These observations of Antarctic marine invertebrates corroborate those recently made about terrestrial mammals and plants in the Arctic.

EARLY CRETACEOUS ARTHROPODS FROM THE TLAYUA FORMATION AT TEPEXI DE RODRIGUEZ, PUEBLA, MEXICO

The arthropod macrofauna from the Middle Member of the lithographic limestones of the Tlayda Formation, in quarries at Tepexi, Mexico, is comprised of marine and nonmarine components. Marine taxa include a new species of flabelliferid isopod, a new genus and species of an anomuran, and a new genus and species of a brachyuran crab. Remains of an arachnid and an odonate nymph represent nonmarine constituents. Previous paleoenvironmental interpretations of a restricted lagoon, with periodic episodes of marine and freshwater influences are consistent with the nature of the arthropod fauna. Isopod remains, represented only by corpses, that resemble moder ectoparasites of fishes suggest that they are directly associated with the abundant fish remains found in the quarries, either as ectoparasites that released their hosts before they died or possibly as scavengers that fed on fish remains. The next most abundant arthropods are the crabs, most of which are corpses, suggesting that this group lived in or very near to the depositional site of the Tlayia Formation. Based upon the new fossil material, the stratigraphic range for the Aeglidae has been extended to span Albian to Holocene time. Extant representatives of this family inhabit fresh water environments of South America.

NEW CRABS FROM THE EOCENE AND OLIGOCENE OF BAJA CALIFORNIA SUR, MEXICO AND AN ASSESSMENT OF THE EVOLUTIONARY AND PALEOBIOGEOGRAPHIC IMPLICATIONS OF MEXICAN FOSSIL DECAPODS

Abstract A new collection of fossil decapod crustaceans from the Cretaceous Rosario Formation, the Eocene Tepetate Formation and the Oligocene El Cien Formation, Baja California Sur, Mexico, has yielded two new genera and several new species, Amydrocarcinus dantei n. gen. and sp., Levicyclus tepetate n. gen. and sp., Eriosachila bajaensis n. sp., Oregonia spinifera n. sp., Archaeopus mexicanus n. sp., and Necronectes nodosa n. sp. Additionally, new occurrences of the previously described Lophoranina bishopi, Xandaros sternbergi, Icriocarcinus xestos, and Lobonotus mexicanus as well as Dardanus cf. D. mexicanus are reported. As part of ongoing work on global evolutionary and paleobiogeographic patterns within the Decapoda, the work has prompted a review and synthesis of decapod occurrences in the tropical and subtropical Americas including the southern United States, the Caribbean, Mexico, Central America, and northern South America. As a result of the systematic review, several new combinations are reported herein which include Eriosachila bartholomaeensis (Rathbun, 1919), Lobonotus sandersi (Blow and Manning, 1996; 1998), and Matutites americanus (Rathbun, 1935). Icriocarcinus is transferred to the Goneplacidae, extending the range of that family into the Cretaceous. Most Cretaceous through Miocene tropical and subtropical American taxa appear to have originated within the area and a large number were endemic. Most of the immigrants to the central Americas appear to have evolved along North Atlantic shelves and subsequently dispersed to the Americas, probably via continental shelf routes. In addition, as demonstrated by several previous studies, decapod crustaceans appear to have evolved in numerous middle- and high- latitude areas with subsequent dispersal to lower latitudes, contrary to the long held notion that the tropics are areas of origin with subsequent dispersal to other regions. Low-latitude decapod taxa tend to remain in low-latitude areas. The Maastrichtian and the Eocene appear to have been times of elevated extinctions within the Decapoda; however, the extinction patterns for those two time intervals are very complex.

Paleobiogeography of Southern Hemisphere decapod Crustacea

Abstract Paleobiogeographic patterns of decapod crustaceans from the Southern Hemisphere, based upon 441 species-level records arrayed in 154 genera, document global patterns of distribution that can be compared to those previously published on decapods from the North Pacific and Central American regions. All known records of decapods from the Southern Hemisphere spanning the Early Triassic to Pleistocene have been compiled, nearly all have been personally verified, and patterns of origin and distribution have been interpreted. Interchange between hemispheres, including amphitropical and bipolar distributions, are recognized from Jurassic to post– Miocene time. The high southern latitudes was a site of origin of several generic-level taxa during the Jurassic through Eocene and many of these taxa have been identified in subsequent times in lower latitude regions in shallow- and deepwater environments in both hemispheres. The isolation of Antarctica due to ocean currents significantly diminished the role of the high southern latitudes as an area of origin for decapods. The Tethys was an important dispersal pathway for decapods during the Cretaceous through early Miocene. Endemism was high during the Eocene, similar to the North Pacific and Central America. The magnitude of the Cretaceous/Paleogene extinction event on the Southern Hemisphere decapod fauna was not profound; most Cretaceous extinctions seem to have occurred well before the end of the Cretaceous, and 85% of the Cretaceous families are known from the Paleogene in the Southern Hemisphere taxa.

A comprehensive and integrative reconstruction of evolutionary history for Anomura (Crustacea: Decapoda).

BackgroundThe infraorder Anomura has long captivated the attention of evolutionary biologists due to its impressive morphological diversity and ecological adaptations. To date, 2500 extant species have been described but phylogenetic relationships at high taxonomic levels remain unresolved. Here, we reconstruct the evolutionary history—phylogeny, divergence times, character evolution and diversification—of this speciose clade. For this purpose, we sequenced two mitochondrial (16S and 12S) and three nuclear (H3, 18S and 28S) markers for 19 of the 20 extant families, using traditional Sanger and next-generation 454 sequencing methods. Molecular data were combined with 156 morphological characters in order to estimate the largest anomuran phylogeny to date. The anomuran fossil record allowed us to incorporate 31 fossils for divergence time analyses.ResultsOur best phylogenetic hypothesis (morphological + molecular data) supports most anomuran superfamilies and families as monophyletic. However, three families and eleven genera are recovered as para- and polyphyletic. Divergence time analysis dates the origin of Anomura to the Late Permian ~259 (224–296) MYA with many of the present day families radiating during the Jurassic and Early Cretaceous. Ancestral state reconstruction suggests that carcinization occurred independently 3 times within the group. The invasion of freshwater and terrestrial environments both occurred between the Late Cretaceous and Tertiary. Diversification analyses found the speciation rate to be low across Anomura, and we identify 2 major changes in the tempo of diversification; the most significant at the base of a clade that includes the squat-lobster family Chirostylidae.ConclusionsOur findings are compared against current classifications and previous hypotheses of anomuran relationships. Many families and genera appear to be poly- or paraphyletic suggesting a need for further taxonomic revisions at these levels. A divergence time analysis provides key insights into the origins of major lineages and events and the timing of morphological (body form) and ecological (habitat) transitions. Living anomuran biodiversity is the product of 2 major changes in the tempo of diversification; our initial insights suggest that the acquisition of a crab-like form did not act as a key innovation.

NEW SPECIES OF CALAPPID CRABS FROM WESTERN NORTH AMERICA AND RECONSIDERATION OF THE CALAPPIDAE SENSU LATO

Abstract Analysis of dorsal carapace characters of fossil and extant genera of the Calappidae sensu lato supports Bellwoods (1996) assignment of the group into four families based upon phylogenetic analysis, which was also supported by previous larval and morphologic studies. The Calappidae sensu stricto, Matutidae, and Hepatidae, recognized by Bellwood (1996), embrace both fossil and extant genera. The Orithyiidae is known from a single extant genus. Additionally, the Necrocarcininae Förster, known only from extinct genera, is elevated to family status. New taxa include Mursia aspina and Eriosachila rossi. Zanthopsis rathbunae Kooser and Orr, 1973, is here referred to Eriosachila orri, n. comb. and nomen novum. Emended descriptions are given for Mursia yaquinensis Rathbun, 1926, and Necrocarcinus hannae Rathbun, 1926. Biogeographic analysis indicates that each family has a distinct origination and dispersal history independent of the other families. Ecologic information for each group suggests that climatic preferences for the extant families have either remained relatively stable since the appearance of each family in the Tertiary or were broader in the past.

Cretaceous and Eocene Decapod Crustaceans from Southern Vancouver Island, British Columbia, Canada

A large collection of fossil decapod crustaceans from Cretaceous and Eocene rocks of Vancouver Island, British Columbia, Canada, has yielded a remarkably diverse fauna. The Cretaceous decapod fauna, including previously described and new taxa, contains 17 genera in 14 families, represented by as many as 22 species. The Eocene fauna is less robust, with 7 species and 6 genera in 6 families. This publication includes one new family; three new genera; eight new species; and nine new combinations. The decapod fauna of the Nanaimo Group supports a position for Wrangellia well north of the current position of Baja California, Mexico. The decapod fauna of the Western Interior of North America is distinct from that of west coastal North America, suggesting limited faunal exchange between the two areas. Fewer than half of the decapod genera present in British Columbia during the Late Cretaceous Period became extinct by the end of the Cretaceous, most before the Maastrichtian. Two of the Cretaceous genera and none of the Eocene genera are extant; the extant genera are both members of the Callianassidae. Of the 14 families present in Cretaceous rocks of British Columbia, five are extinct. The North Atlantic and Central Americas appear to have been areas of rapid evolutionary expansion within the Decapoda during the Cretaceous, based upon the large number of decapod families that appear to have originated there during Cretaceous time.

REVISION OF PORTUNOIDEA RAFINESQUE, 1815 (DECAPODA: BRACHYURA) WITH EMPHASIS ON THE FOSSIL GENERA AND FAMILIES

Abstract The superfamily Portunoidea including extinct lineages is herein evaluated via cladistic analysis of adult morphological characters and traditional systematics. Nearly every fossil species has been examined via type material, or if this was not possible, through illustrations and original descriptions. The analyses indicate that the superfamily is much more diverse at the family level than has previously been recognized, and three subfamilies, Catoptrinae, Carcininae, and Macropipinae, are herein elevated to family status. One new family, Longusorbiidae; two new genera, Euronectes and Viaophthalmus; and two nomen nova are named herein in addition to the recognition of seven new combinations. The fossil record of each of the resulting families is evaluated and summarized, indicating that the superfamily extends into the Cretaceous but that many of the families are indeed much younger lineages.

NEW EOCENE DECAPODS (THALASSINIDEA and BRACHYURA) FROM SOUTHERN CALIFORNIA

A new decapod fauna has been recovered from Eocene rocks of San Diego County, Califomia. Decapod faunas of Eocene age have been rare from Califomia, although they are well described from the northern Pacific coast. Three new species, including Ncocallichirus rhinos, Ctenocheles secrctanae, and Minohellenus inexpressus, and two new genera and species, Acanthoportwms huchaiumi and Vegarfhron Santiago, are reported from this new fauna. A new genus has been erected to accommodate Portuniles triangulum and Portuniles granulifer; both are herein referred to Maeandricainpus, new genus. Callianassa matsoni Rathbun has been reassigned to Neocallichirus. Portions of the cephalothorax and abdomen of a species of Ctenocheles are described from fossils for the first time. Orhitoplax weaveri, previously known from Eocene rocks of Califomia and Oregon, is reported from the Eocene Mission Valley Formation and the Ardath Shale for the first time. In addition, one specimen of a stomatopod of indeterminate genus is noted. The Eocene decapod fauna from Califomia, now containing eighteen genera, has elements common to the northern Pacific coast of North America as well as taxa known only from Califomia; thus, the area appears to have been suited for decapods adapted to a wide variety of temperature and other environmental conditions. Several genera appear to have evolved within the region, whereas others may have been introduced from the Atlantic or Tethys region via the Central American Seaway. The number of Pacific amphitropical genera continues to increase; two portunid genera discussed here display such a pattern, adding to the four already reported for Cretaceous and Tertiary rocks of the region. Fossil decapod crustacean faunas have been well described from the Pacific Northwest of North America (see Schweitzer, 2001, for summary) and from Baja Califomia (Rathbun, 1930; Squires and Demetrion, 1992; Schweitzer et al., in press); however. Eocene decapods from Califomia have been relatively uncommon. Isolated occurrences of decapods have previously been described from Califomia (Rathbun, 1926, 1932; Squires, 1980, 2001; Bishop, 1988; Tucker et al, 1994). The discrepancy between numbers of Eocene occurrences in Califomia as opposed to areas to the north of that state was speculated to have been a result either of the paucity of Eocene rocks in Califomia or of differential evolutionary rates in the two areas (Schweitzer, 2001). It now appears that as new material is collected and made available for study, the Eocene record will become increasingly robust. The fauna described here is significant because it is one of the few Eocene decapod faunas known from the Califomia coast and brings to at least eighteen the total number of decapod genera now known from the Eocene of Califomia. The new material described in this report includes two new genera that appear to be endemic to the region as well as a new species of a genus not previously known from the Eocene of the west coast of North America. Further, three species are described here that are referable to genera already well-known from Tertiary rocks of the northern Pacific coast of North America. This mixture of taxa known only to the southern Pacific coast with taxa previously reported from farther north suggests that the Califomia coast was a region where taxa from the cooler northern provinces mixed with taxa derived from tropical regions to the south. OCCURRENCE OF FOSSILS A summary of locality information may be found in Table 1. The specimens described here from Localities 4572, 4573, and 4109 were collected from member B of the Santiago Formation of early Uintan (middle Eocene) age (Golz and Lillegraven, 1977). The Santiago Formation is composed of approximately 600 m of yellow sandstone underlying the Sespe and Vaqueros formations and overlying the Silverado Formation (Schoelihammer et al., 1981). The contacts with the underlying and overlying units are in

Decapod and Stomatopod crustaceans from mass mortality Lagerstatten; Turonian (Cretaceous) of Colombia

Mass mortality surfaces and bioclastic lags in Turonian siliceous shales of the San Rafael and La Frontera formations in Colombia have yielded two species of decapod crustaceans, Opthalmoplax spinosus new species and Pinnotheres? species indeterminate, as well as one stomatopod. Sculda sp. All represent first records for the country. Remains of the swimming carcineretid crab, Opthalmoplax spinosus, in association with fish fragments and pelagic ammonites, cover mass mortality surfaces. The occurrence suggests that the high density living population of the crabs, exploiting abundant food resources in areas of topography-controlled upwelling, was periodically reduced catastrophically, perhaps by advection of toxic trace elements or by oxygen starvation. Two other taphofacies, characterized by current oriented appendage fragments and scattered skeletal elements represent normal accumulations of fossil material in the San Rafael and La Frontera formations.