Results of the Puritan-American Museum of Natural History Expedition to Western Mexico. 18, Cyclostomata, Ctenostomata (Ectoprocta), and Entoprocta of the Gulf of California. American Museum novitates ; no. 2144

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New York, N.Y. : American Museum of Natural History
"Tabulation (see table 1) of the bryozoans, Ectoprocta, and Entoprocta in the present collections reveals the numerical superiority of the suborder Cheilostomata, with 131 species. The Anasca Cheilostomata have 56 (Soule, 1959); the Ascophora Cheilostomata, 75 (Soule, 1961). The present report describes 15 species of the suborder Cyclostomata, 13 species of the suborder Ctenostomata, and one representative of the phylum Entoprocta. Thus the total number of species of bryozoans in the Puritan collection is 160. Further analysis of this Puritan collection reveals that there are 59 species reported from the Gulf of California for the first time. In addition, the Puritan collection adds 13 species to the Panamic faunal list, contains four species previously unknown to the waters of the eastern Pacific, and, lastly, adds nine new species, all in the suborder Cheilostomata, to the phylum. With the exception of the new species, all the bryozoans in the Puritan collection have been reported from faunal provinces other than the Panamic province. Additional collections and study will be needed to demonstrate instances of endemic species in the Gulf of California. At the completion of Osburn's study of the eastern Pacific bryozoans (1950-1953), 133 species were recorded from the Gulf of California. With the additional material provided by the Puritan-American Museum expedition, the bryozoan fauna of this region now numbers 200 species. In a recent paper (Soule, 1960), a brief account was given of the distribution and faunal affinities of the bryozoan fauna of both the Gulf of California and the Pacific coast of Baja California. It was based in part on Osburn's 1950-1953 monograph and in part on the study of the Puritan collection that was in progress at that time. This paper indicated, with regard to the bryozoans, that in its faunal affinities, the Gulf of California is decidedly Panamic in character. With the study of the Puritan collection now complete, the faunal affinity picture is not appreciably changed. As can be seen in table 1, the fauna is strongly Panamic, followed in decreasing order by representatives of the eastern Pacific (exclusive of the Panamic faunal province), the West Indies, and the Indo-Pacific. The study of the distributional pattern of the bryozoans of the Puritan collection within the Gulf of California reveals three areas, only slightly revised by additional material from the earlier study (Soule, 1960). As shown by the map (fig. 1), the southern one-third of the Gulf of California supports a bryozoan fauna that is distinctly tropical ... It is continuous with a region on the Pacific coast of Baja California ... In the Gulf of California, immediately north of the tropical area, is a central zone of transition ... On the Pacific coast of Baja California, there is a similar zone of transitional type ... In the Gulf of California, the remaining 300 linear miles north of the transitional zone possesses a fauna that can be referred to as subtropical ... A third zone is present on the Pacific coast of Baja California, which differs substantially from the northern area of the Gulf of California. Here, except for major embayments such as Scammon's Lagoon, is found a warm temperate fauna ... This zone extends from Point Eugenia northward above the political boundary between Baja California Norte and California, to meet the cool temperate waters at Point Conception, California"--P. 28-29.
34 p. : map ; 24 cm.
Includes bibliographical references (p. 30-34).