Zoogeography and ecology of some macro-invertebrates, particularly mollusks, in the Gulf of California and the continental slope off Mexico

Abstract

A reconnaissance study of the zoogeography and ecology of benthic invertebrates in the Gulf of California and on the continental slope off west Mexico was carried out during the years 1958-1963. A series of characteristic assemblages were devised for various environments found in the Gulf of California, derived from both 272 biological samples and the distribution of approximately 1,150 identified species of invertebrates. Using a contingency matrix of common occurrences of 280 common species of invertebrates, compiled by a digital computor as a basis for preliminary analysis it was possible to designate 12 separate assemblages of invertebrates. These assemblages reflected distinct environmental regions of uniform depth, sediment, water temperatures and oxygen concentrations. These environments and their assemblages are as follows: I. Intertidal and shallow rocky shores; II. Intertidal beaches and sand flats to 10 meters; III. Low salinity lagoons and mangrove mudflats; IV. Nearshore shelf,

Ingestion of quill‐worms by the astropectinid sea‐starProserpinaster neozelanicus(Mortensen)

“…and also the tracks (lebensspuren) quill-worms leave as they travel across the bottom (Parker 1963;Ewing & Davis 1967;Wigley & Emery 1967;Grassle et al 1975;Hecker 1994). In the same zone in New Zealand waters Hyalinoecia spp.…”

Marine and brackish-water molluscan biodiversity in the Gulf of California, Mexico

“…The coastal length is estimated at 4512 km. Coastal measurements were made using a digital map which provided a 235 m definition, i.e., one pixel represented 235 m. Of these 4512 km, about half is occupied by sandy shores, a dominating feature on the east and northern coasts; rocky shores and cliffs are characteristic of the Baja California peninsular coast, while a regular fresh water supply is almost exclusively restricted to the SE extremity of the Gulf where coastal lagoons and estuaries dissect the coastal plain (Parker, 1964;Brusca, 1980;Hendrickx, 1992;Brusca et al, 2004).…”

Molluscan paleontology of the lower Miocene Clallam Formation, northwestern Washington

“…The other genera are suggestive of somewhat shallower water conditions in terms of their known depth ranges. Solamen ranges from about 30 m into the upper bathyal zone (Soot-Ryen, 1955) along the Pacific coast, and Lucinoma annulata (Reeve), a homologue of the Oligocene and Miocene species L. acutilineata, ranges from about 15m (Smith and Gordon, 1948) to bathyal depths (Parker, 1963) in the eastern North Pacific.…”

“…They list a species of Anadara as the sole mollusk from a locality (NP162) at the Clallam coal mine which is within a few hundred metres, geographically, of locality M4683, and presumably at, or near the top of, the Clallam Formation. The occurrence of this bivalve, without any other mollusks, may be indicative of extremely shallow water, possibly intertidal, conditions inasmuch as Anadara in the northern part of its modern geographic distribution off Mexico today is characteristic of low taxonomic diversity assemblages from lagoonal and mangrove swamp environments (Parker, 1963;Keen, 1971).…”