Californian Province Research Articles

Systematic relationships of sympatric pipefishes (Syngnathus spp.): A mismatch between morphological and molecular variation.

Analyses of mitochondrial DNA and morphological variation were performed on specimens of all five currently recognised Syngnathus pipefish species from the eastern Pacific Ocean with type localities currently considered to lie within the Californian marine biogeographic province: kelp pipefish Syngnathus californiensis, bay pipefish S. leptorhynchus, barred pipefish S. auliscus, barcheek pipefish S. exilis and chocolate pipefish S. euchrous. Results consistently differentiate S. auliscus from the other species and fail to distinguish all other specimens as distinct species, as indicated by extensive morphological overlap as well as incomplete lineage sorting and considerably low genetic divergence for 16s and coI genes(<1%). This study presents a taxonomic revision of eastern Pacific Syngnathus spp. and proposes the synonymy of S. leptorhynchus, S. euchrous and S. exilis, under the senior synonym, S. californiensis. There is still a need to study populations of Syngnathus spp. from north and south of the Californian province to assess whether these too are synonyms of the two-species recognised here.

A new species of the genus Policordia (Bivalvia, Verticordioidea, Lyonsiellidae) from off the coast of southern California.

A new species, Policordia hispida, is described and compared with three similar species: Policordia densicostata (Locard, 1898); Policordia pilula (Pelseneer, 1911) and a yet un-described species, Policordia sp. (= Policordia pilula sensu Ivanova, 1977 not Pelseneer, 1911). This is a first record for the genus in the Californian province.

Relaxation Time and the Problem of the Pleistocene

Although changes in habitat area, driven by changes in sea level, have long been considered as a possible cause of marine diversity change in the Phanerozoic, the lack of Pleistocene extinction in the Californian Province has raised doubts, given the large and rapid sea-level changes during the Pleistocene. Neutral models of metacommunities presented here suggest that diversity responds rapidly to changes in habitat area, with relaxation times of a few hundred to a few thousand years. Relaxation time is controlled partly by metacommunity size, implying that different provinces or trophic levels might have measurably different responses to changes in habitable area. Geologically short relaxation times imply that metacommunities should be able to stay nearly in equilibrium with all but the most rapid changes in area. A simulation of the Californian Province during the Pleistocene confirms this, with the longest lags in diversity approaching 20 kyr. The apparent lack of Pleistocene extinction in the Californian Province likely results from the difficulty of sampling rare species, coupled with repopulation from adjacent deep-water or warm-water regions.

Lista sistemática de la ictiofauna de la Reserva de la Biosfera La Encrucijada, Chiapas, México

We provided a systematic checklist of fishes recorded on La Encrucijada Biosphere Reserve (REBIEN), during the period from 2004 to 2009. The systematic list is composed by 153 species that are included in 2 classes, 20 orders, 52 families and 107 genera. Nine species are added to the known continental environments of the state of Chiapas, 4 of them are registered by first time in estuarine-lagoon biotopes of Mexico: Cathorops cf. fuerthii, Trichiurus nitens, Guavina micropus and Gobionellus liolepis, the last 2 species are reported for the first time in the Mexican pacific; the presence of the exotic cichlid Oreochromis niloticus is also reported. The best represented families in species richness were Carangidae (14), Sciaenidae (11), Gobiidae (10) and Ariidae (9). Based on its ecogeographical derivation, 4 species (2.6% ) are freshwater primary; 13 (8.5%) freshwater secondary, and 134 (88.9%) peripheral; the last group is ecologically composed by 3 catadromous species (2%), 11 estuarine residents (7.2%), 56 marine euryhalines (36.6%) and 66 marine stenohalines (43.1%). Biogeographically, 91.2% of the species are distributed in Eastern Pacific, 47.7% are from the Californian province, 65.4% from Cortes province, 80.4% from Panamian province, and 41.2% from Peruvian province. Comparatively, the REBIEN contains the highest fish richness in all the estuarine-lagoon systems along the Mexican Pacific.

Isópodos litorales y de aguas someras de la bahía de Todos los Santos, Baja California, México

A checklist of the free-living isopods of Todos los Santos Bay, Baja California, is presented on the basis of allochronic collections made between 1988 and 2005 along the rocky, sandy, and muddy intertidal and sandy subtidal to 256 meters deep. We collected 26 of the 48 species known from the Californian province: 2 Asellota; 7 Cymothoida; 1 Oniscoidea; 7 Sphaeromatidea; 9 Valvifera. The most abundant species were Excirolana linguifrons (Richardson, 1899), (sandy mesolitoral), Idotea fewkesi Richardson, 1905 and I. resecata Stimpson 1857, (rocky intertidal), Haliophasma geminatum Menzies and Barnard, 1959, (muddy intertidal and subtidal associated with the eel grass Zostera marina), and Caecognathia crenulatifrons (Monod, 1926) (sublitoral). All the recorded species were found in similar marine biotopes in California, USA. Of the 26 species, 7 are recorded for the fi rst time in Mexico, extending their southern distribution to Todos los Santos Bay. These are: Erichsonella crenulata Menzies, 1950, Exosphaeroma amplicauda (Stimpson 1857), E. octonum (Richardson, 1899), Idarcturus allelomorphus Menzies y Barnard, 1959, I. fewkesi, Janiralata davisi Menzies, 1951 and Paracerceis gilliana (Richardson, 1899).

Late Pliocene fossils of Ecuador and their role in the development of the Panamic bioprovince after the rising of Central American Isthmus

Studies carried on in the last several years allow us to date the Canoa Formation as Late Pliocene. The rich paleontological record (foraminifers, mollusks, and otoliths) allowed us to outline a first articulate picture of the biogeographic relationships in the tropical eastern Pacific during the Plio-Pleistocene. The mollusk fauna shows a Panamic connotation, as the majority (88.7%) of the extant species are present between the Gulf of California and the coasts of Ecuador or northern Peru. Benthic foraminifers assemblages indicate a temperate character with a certain affinity with the Mexican Pacific microfauna. More than 7000 otoliths have been found in the Canoa Formation that are attributed to 105 taxa of 46 fish families. Only 65% of the fossil association is living today along the Ecuadorian coasts, while the association as a whole shows closer relationships with the extant Californian fish community (about 80%). In particular, a conspicuous group of fishes (15 taxa) today spread in the boreal East Pacific (from Oregonian to Californian Province or limited only to the Californian area) has been recorded in the Canoa Formation. We named these taxa "Californian guests." After the rising of the Central American Isthmus, climatic variations may have caused changes in the pattern of surface currents and (or) activated coastal upwelling cells, supporting the diffusion of a part of the boreal biota toward more southern areas. At the present state of knowledge, both proximal causes seem to be compatible with the data presented.

On Monstrilla Spinosa Park, 1967 (Copepoda, Monstrilloida) in the Eastern Pacific

[The monstrilloid copepod Monstrilla spinosa was only known from one cold temperate site in the Northwestern Pacific (Aleutian-Oregonian Province), and has not been directly observed since its original description in 1967. This species was found in Bahia de Todos Santos, Baja California, Mexico, a new locality for the species in the Pacific warm temperate zone (Californian Province). The specimens (three females) differ from the type material in total length, antennular relative length, and cuticular ornamentation. Zoogeographical considerations are made with the available data on the distribution of the species., The monstrilloid copepod Monstrilla spinosa was only known from one cold temperate site in the Northwestern Pacific (Aleutian-Oregonian Province), and has not been directly observed since its original description in 1967. This species was found in Bahia de Todos Santos, Baja California, Mexico, a new locality for the species in the Pacific warm temperate zone (Californian Province). The specimens (three females) differ from the type material in total length, antennular relative length, and cuticular ornamentation. Zoogeographical considerations are made with the available data on the distribution of the species.]

How good was the fossil record? Clues from the Californian Pleistocene

The living members of 113 families of bivalves and gastropods of the Californian Province include 698 species living at shelf depths, of which 538 or 77% are known as Pleistocene fossils from the same region; another 113 fossil species are extralimital, and 98 are extinct. Living species not found as fossils are chiefly rare today, and/or minute, fragile, and/or from deeper shelf habitats. Sampling of the Pleistocene record has been biased towards shallow-water assemblages. Fragile and minute forms are probably underrepresented in the record. Rare forms, however, are still appearing as new studies are conducted, and many rare species are yet to be discovered. At least 85% of durably skeletonized living species may have been captured in the record. It is probable that most durably skeletonized invertebrate species were represented in lithostratigraphic units throughout the Phanerozoic, but that this record is lost owing to erosion, burial, and destruction of skeletons in situ. The bulk of the marine invertebrate fossil record does not represent a series of unusual skeletal accumulations, but rather the preserved remnants of an excellent original record formed through ordinary though episodic processes.

Outline of Eastern North Pacific Fossil Cetacean Assemblages

Barnes, Lawrence G. (Section of Vertebrate Paleontology, Natural History Museum of Los Angeles County, Los Angeles, California 90007) 1976. Outline of eastern North Pacific fossil cetacean assemblages. Syst. Zool. 25:321-343.-Geologic formations on the west coast of North America from Baja California, Mexico to central California, U.S.A., provide fossil evidence for a succession of Tertiary cetacean assemblages. Formations representing time periods of stage magnitude from early Miocene to Pleistocene age produce diverse aggregates of Cetacea containing fewer species than can now be found in latitudes corresponding to the Californian Province in the Pacific Ocean. Most fossil assemblages include a sperm whale, several dolphin-like taxa, and 3 or 4 baleen whales, although taxonomy is unstable, and many specimens cannot be assigned to named genera and species. New records of the earliest North Pacific occurrence of the families Balaenidae, Ziphiidae, Monodontidae, Phocoenidae, and Delphinidae (sensu stricto) date from the Miocene, and of the Eschrichtiidae from the Pleistocene. Squalodontidae are notable by their rarity. Early Miocene assemblages are dominated by Eurhinodelphidae, and late Tertiary ones by Stenodelphininae and primitive Balaenopteridae. On the generic level, there is a high degree of endemism among small Odontoceti, and a low degree among Physeteridae and Mysticeti. Collecting biases and deficiencies prevent recognition of antitropical distributions of fossil taxa, and paleoclimatology can not yet be inferred from the fossils. The status of the knowledge of fossil Cetacea in marine sedimentary deposits along the western border of North America is such that a summary and prospectus can now be formulated. A variety of Cenozoic fossil cetaceans are documented in the existing paleontologic literature, but these in no way reflect the real abundance of taxa or of specimens in the field or in museum collections. This article is in part, therefore, a summary of previously unrecorded specimens under study by the author (Barnes, 1972b). Mitchell (1966b) presented an earlier, more popularized overview of marine mammal evolution in the North Pacific Ocean. More fossil species are now represented by skulls and skeletons than previously, and some new interpretations of taxonomy and morphology are forthcoming in more detailed studies. These more complete specimens provide, in some cases, an opportunity for more precise determinations of phylogenetic and taxonomic relationships than was possible in the past for taxa founded upon fragmentary specimens. Kellogg (1923:38) has pointed out that comparisons among many fossil Cetacea have been hampered because of the lack of directly comparable parts of skeletons. Additionally, some taxa are described from skeletal parts having dubious taxonomic value. Cope (1868a, 1868b), Leidy (1851, 1869), and Deraniyagala (1969) have used isolated vertebrae and teeth, and Kellogg (1931) has used isolated periotics. In reality, both convergence and evolutionary conservativism may cause vertebrae and even teeth to be non-diagnostic in cetaceans. Even the isolated periotic has been proven, among Recent Cetacea, to sometimes be only generically and not specifically identifiable (Kasuya, 1973:72). This is particularly true for species of Kogia Gray, 1846 and for Delphinus bairdi Dall, 1873 and Stenella attenuata Gray, 1846 (see Kasuya, 1973:figs. 71-72). Recently, Ginsburg and Janvier (1971); and Hatai, Hayasaka, and Masuda (1963), have used isolated teeth and auditory bullae as holotypes. In light of such recent digressions in the quality of fossil cetacean systematics, I recommend that all subsequent cetacean holotypes include at least skull parts,

The Marine Vertebrates of the Outer Coast

IT IS ONLY a first, in fact a very crude approximation, to include the Gulf coast of Baja California and the tip of the peninsula in the tropical Panamic Province and the rest of the outer coast in the warm-temperate (San Diegan) division of the Californian Province. The faunal changes along the outer coast of Baja California, in particular, are neither so abrupt nor so regular as to justify drawing definite boundaries to such provinces. The facts of the distribution of life along this coast emphasize the serious doubts that may be entertained regarding the wisdom of attempting a definite areal zoogeographic classification along an hierarchic system. It may well be more meaningful and dynamic to treat each areal faunal assemblage as a complex of faunal elements of diverse provenance, as Mayr (1946) and Parkes (1958) have done for the birds of North America.

A SYNOPSIS OF THE RECENT AND TERTIARY FRESHWATER MOLLUSCA OF THE CALIFORNIAN PROVINCE, BASED UPON AN ONTOGENETIC CLASSIFICATION

A SYNOPSIS OF THE RECENT AND TERTIARY FRESHWATER MOLLUSCA OF THE CALIFORNIAN PROVINCE, BASED UPON AN ONTOGENETIC CLASSIFICATION HAROLD HANNIBAL HAROLD HANNIBAL Search for other works by this author on: Oxford Academic Google Scholar Journal of Molluscan Studies, Volume 10, Issue 3, October 1912, Pages 167–211, https://doi.org/10.1093/oxfordjournals.mollus.a063488 Published: 01 October 1912 Article history Received: 10 May 1912 Published: 01 October 1912