Pacific Plate Biogeography, with Special Reference to Shorefishes VICTOR G. SPRINGER m SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 367 SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTION Emphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the Institution, Joseph Henry outlined a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This theme of basic research has been adhered to through the years by thousands of titles issued in series publications under the Smithsonian imprint, commencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoo/ogy Smithsonian Studies in Air and Space Smithsonian Studies in History and Technology In these series, the Institution publishes small papers and full-scale monographs that report the research and collections of its various museums and bureaux or of professional colleagues in the world cf science and scholarship. The publications are distributed by mailing lists to libraries, universities, and similar institutions throughout the world. Papers or monographs submitted for series publication are received by the Smithsonian Institution Press, subject to its own review for format and style, only through departments of the various Smithsonian museums or bureaux, where the manuscripts are given substantive review. Press requirements for manuscript and art preparation are outlined on the inside back cover. S. Dillon Ripley Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 367 Pacific Plate Biogeography, with Special Reference to Shorefishes Victor G. Springer SMITHSONIAN INSTITUTION PRESS City of Washington 1982 ABSTRACT Springer, Victor G. Pacific Plate Biogeography, with Special Reference to Shorefishes. Smithsonian Contributions to Zoology, number 367, 182 pages, 65 figures, 5 tables, 1982.—It is the thesis of this study that the Pacific lithospheric plate (Pacific Plate) forms a major subunit of the Indo-Pacific biogeographic region. This thesis is defended on two primary grounds: the sharp decrease in numbers of taxa as one proceeds eastward across the western margin of the Pacific Plate, and the presence of a high degree of endemism on the Plate. The complex geotectonic history of the Plate and adjacent plate margins is discussed and the vicariance scenarios that produced the three main types of endemism (widely distributed Plate endemism, endemism restricted to a limited region on the Plate, and endemism restricted to single islands or island groups) are hypothesized. Anecdotal discussions of the distributions of 179 shorefish family groups are presented, as well as discussions of the distributions of selected terrestrial and marine taxa of other organisms. Particular attention is given to presumed erroneous or exceptional distributions of fishes on the Pacific Plate, including, but not limited to, north-south disjunct distributions, Hawaiian Islands' exceptional distributions, and distributions involving the Caroline Islands, which serve as stepping stones for dispersal onto the Pacific Plate. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavemosa (Linnaeus). Library of Congress Cataloging in Publication Data Springer, Victor Gruschka, 1928- Pacific Plate biogeography, with special reference to shorefishes. (Smithsonian contributions to zoology ; no. 367) Bibliography: p. Supt. of Docs, no.: SI 1.27:367 1. Fishes—Indo-Pacific Region—Geographical distribution. 2. Biogeography—Indo-Pacific Region. 3. Fishes—Pacific Ocean—Geographical distribution. 4. Geology—Pacific Ocean. I. Title. II. Title: Shorefishes. III. Series. QL1.S54 no. 367 [QL623.98] 591s [591.92'5] 82-600146 AACR2 Contents Page Introduction 1 Acknowledgments 7 Methods 7 Distribution Maps 7 Terminology 8 Pacific Plate Distributions 8 Family-Group Names 9 Classification 9 Abbreviations 9 Organization of the Study 9 Distributions of Indo-Pacific Organisms 9 Shorefishes 9 Other Organisms 105 Phylum MOLLUSCA 105 Class GASTROPODA 105 Class PELECYPODA 108 Class CEPHALOPODA 108 Phylum ARTHROPODA 109 Class CRUSTACEA 109 Class INSECTA 113 Phylum CHORDATA 114 Class MAMMALIA 114 Plants 115 Discussion 117 Numbers of Shorefish Families 117 Numbers of Shorefish Genera and Species 119 Boundary Effect between Pacific Plate and Indo-West Pacific 120 Reality Hypothesis 121 Extinction Hypothesis 124 Endemism 127 Endemicity of Shorefish Families and Genera 127 Endemicity of Shorefish Species 128 Hawaiian Islands and North-South Disjunct Distributions on the Pacific Plate 130 Easter Island 136 Marquesas Islands 139 Geological History of the Pacific and Philippine Plates and Adja- cent Margins as Related to Formation of Types 1 and 2 Endemics 143 Epilogue 148 iii SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY Addendum 149 Appendix 1: The Andesite Line 150 Appendix 2: Tables 153 Table A 153 Table B 157 Table C 157 Literature Cited 162 S FOR PACIFIC PC.A'l'F. HIGCKOCNAPH\ Page 10, Fig. 5. Arantrhurua arhil)e.i has been reported from th* southern tip oi ba)u Calltornla based on a aight record (D. A. Thomson, et al., Iy7d, Reoy Fi ahea o£ the S«?a_ o£ Corte?) Page 15, col. 1, line 14. replace tarnycrphalua with Page 25. Replace fcranchioategicUe with Latllidae Page 27. Under Curacanthidae. Mizuno and Tooinaga were in errori carac&nchlda are not present at the Galapagos (M. and T, In lite, to W.N. Eschmeyer, pers. coum.) Page 28, col. 1, penultimate line. Replace carupodid with carapid Page 60. Replace Monocentrldae with Honocentrididae Page 63. Under Nomeldae, 7th and Uth lines iron bottom delete the three words "eastern Atlantic and" Page 88, Figure 39 caption. Delete sentence, "While this study was in press..." Sarrta is not known from Fili. Page 91. Under Scorpididae. Delete Parapaetno Lbelongs in EphlppldldaeJ Page 100. Under Torpedlnlfornes and figure 44. 1 missed a report or the occurrence of electric rays on the Nazca Hidqe, Nazca Plate. Page 149, right column, 4th line, replace corroroborare with corroborate. Page 165. Under Chubb, replace 1*74 with Pacific Plate Biogeography, with Special Reference to Shorefishes Victor G. Springer Introduction The Pacific Plate (Figures 1,2) is the largest of effects for the distribution of Pacific Basin orga- all the earth's lithospheric plates and occupies nisms. most of the area that has been referred to as the My study is concerned primarily with the dis- Pacific Basin (Figures 3, 4). Although the Pacific tributions of the shorefishes of the Indo-Pacific as Basin has been the subject of numerous biogeo- these distributions relate to the Pacific Plate. I graphic studies, there are only two studies (Sprin- propose to demonstrate that the Pacific Plate ger, 1981a; Rotondo et al., 1981) that have al- defines a biogeographic region of major signifi- luded to the Pacific Plate as a separate biogeo- cance, and I will hypothesize the biological and graphic unit. I will not recount the Pacific Basin geological factors that produced the region. I literature here, but refer the reader to two studies believe that study of the Pacific Plate provides that together summarize the subject admirably. new insights into the patterns of organismal dis- Van Balgooy (1971) gave a comprehensive and tributions in the Indo-Pacific, both aquatic and scholarly rendering of the general literature on terrestrial. From this it follows that many of the Pacific Basin biogeography in his analysis of Pa- constraints to dispersal ordinarily invoked to ex- cific plant distributions. The main deficiencies of plain only the distributions of endemic terrestrial van Balgooy's treatise are the absence of reference and freshwater organisms are equally important to the importance of plate tectonics (a subject in explaining the distributions of endemic, shal- probably too new for him to have incorporated) low-dwelling marine organisms. and the use of a solely phenetic approach to The day I began to write this introduction, I relationships. Zoogeographers seem to be una- received a new issue of American Scientist that ware of van Balgooy's work, which merits wider included an article on chance dispersal by attention than it has received. Kay (1980), who Carlquist (1981). In that article (p. 415) was the did not cite van Balgooy, published an excellent following statement, "Those who investigate or- essay on the development of ideas concerning ganisms capable of long-distance dispersal have Pacific Basin biogeography and included a brief not adopted the methods of vicariance biogeog- discussion of the importance of plate tectonic raphy." If this is true, my study is an exception; many shorefishes appear to be so capable. The Victor G. Springer, Department of Vertebrate Zoology, National land masses of the Pacific Plate are islands (Figure Museum of Natural History, Washington, D.C. 20560. 2), many of which are highly isolated, and I will 1 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY o o 8 sfl C T S o a. £ § « .s c •a -o C •- 8 -S .S | ill! ] 21 § .1 3 H a. -g 8 8 • I i i I -S s ^ -I % 8 3 s § 8. a T5 -sp a E act « 6 - £ O O o -S c/3 Sa. u S c iijlij j S .2, S S S NUMBER 367 II * 8. U Q. s < •o g * S < .s c £ u en (0 r- £ j|c 'So « e •- J2 « c I | 8. M S t " o u u, .£ c SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY NUMBER 367 rely heavily on vicariant events to develop hy- potheses to explain endemism among these is- lands. Carlquist apparently thought he was pointing out a weakness in the methodology of vicariance biogeography (Nelson and Platnick, 1981; hence- forth, I refer to the subject as vicariography), but he failed to realize that dispersal is not the ma- terial of that discipline.