Pacific Plate Biogeography, with Special Reference to Shorefishes

NUMBER 367
exception: eastern Pacific taxa (for instance, the
fish family Girellidae) that reach their western
distributional limits at Easter Island, are not
considered to be Pacific Plate taxa. Some Pacific
Plate taxa that have their western distributional
limits along the western margin of the Philippine
Plate, usually the northern portion of that margin,
are considered to be Pacific Plate restricted.
The reasons for this consideration are explained
in the discussions of Types 1 and 2 endemism.
FAMILY-GROUP NAMES.—With the exception of
Carapidae, I follow Steyskal (1980) for the spelling
of family-group names of fishes. Steyskal informs
me that his use of Carapodidae for this
family was based on an erroneous treatment of
the stem.
CLASSIFICATION.—I follow Compagno (1973a)
for the classification and composition of the elasmobranchs
(sharks and rays). Most of the other
shorefish family groupings are those usually rec-
Shorefishes
In the discussions that follow, families known
to occur within the warm shallow waters of the
Indo-Pacific region are presented. Their arrangement
is alphabetical to facilitate locating them,
and follows the listing in Table A (Appendix 2).
The information given focuses on how the family
distributions, and those of the taxa within the
families, relate to the Pacific Plate. Attention is
given to presumed erroneous Pacific Plate distributions
that surfaced in the course of my investigations.
These presumed erroneous distributions
are tests of the validity of my proposition that the
Pacific Plate is a biogeographic unit. The weight
of evidence for this proposition was so heavy that
I was able to presume distributions might be
erroneous only because they represented exceptional
occurrences of a taxon that was otherwise
distributed only on or off the Plate. Subsequent
Distributions of Indo-Pacific Organisms
ognized in the ichthyological literature, and
where I differ, I cite references, colleagues, or
other reasons for my usage.
ABBREVIATIONS.—The following abbreviations
are employed: FL = fork length; m.y. = million
years; SL = standard length; TL = total length;
NMNH = National Museum of Natural History,
Smithsonian Institution; USNM = United States
National Museum collections, Division of Fishes,
NMNH.
ORGANIZATION OF THE STUDY.—The study is
presented as follows: (1) consideration of shorefish
distribution patterns within each family and of
the distributions of other organisms; (2) a general
descriptive synthesis of shorefish distributions on
and off the Pacific Plate, with discussion of hypotheses
for explaining those distributions; and
(3) discussions of patterns of endemism on the
Pacific Plate and the formation of hypotheses to
explain those patterns.
examination of the records on other grounds tends
to confirm the suspicion of error.
By treating the Pacific Plate as the "hole in a
doughnut," one can define the Plate just as surely
by what is absent as by what is present. For this
reason I have presented distribution maps of numerous
taxa (orders, families, genera, species)
that reach the margins of the Plate but do not
extend beyond. In some instances, ichthyologists
have stated that the absence of a taxon from
Oceania is a result of lack of collecting. I believe
that the discussions and distribution maps will
overwhelmingly demonstrate that such assumptions
are often unwarranted.
One locality, the Hawaiian Islands, frequently
represents an area where valid exceptional occurrences
of taxa appear nonmarginally on the
Pacific Plate. I term each such occurrence an
"Hawaiian exception." Discussion of the Hawaiian
Islands will be found in the section on