The Sponges of Micronesia, Part I 
The Palau Archipelago 
Patricia R. Bergquist 1 
ALTHOUGH potentially interesting from a zoo- 
geographic standpoint, the marine fauna of the 
Palau Islands and of the islands and atolls to 
the eastward, with the exception of Hawaii, 
have received scant attention from expeditions 
and individual collectors. It was to repair this 
gap in our knowledge that the "Project Coral 
Fish” expeditions to the western and central 
Pacific were undertaken. The first of these ex- 
peditions visited the Palau Islands in 1955 and 
made extensive marine collections, of which 
the sponges described below were a part. 
Previous work relating to the Demospongiae 
of the Palau Islands is restricted to de Lauben- 
fels’ (1954) "Sponges of the West Central 
Pacific.” This monograph was based upon the 
author’s own collections in the Caroline Islands, 
Marshall Islands, and the Marianas; and it con- 
tains, in addition to descriptions of many new 
species, significant field observations which 
have facilitated identification of the present 
collection. There are 33 species common to the 
two collections and the identification of these 
has necessitated considerable revision of por- 
tions of de Laubenfels’ monograph. 
The Palau Islands belong to the Western 
Caroline group and are situated on a submarine 
ridge running northeast from the Moluccas at 
6° 53' N to 8° 06' N, 134° 29' E. Between 
the Palaus and the Philippines is the Philip- 
pine Trench, which acts as an effective natural 
barrier to the free migration of shallow-water 
invertebrates. Consequently, zoogeographic in- 
terest in the Palau area focuses on whether the 
fauna has remained similar to that of the Indo- 
Malayan region, through interchange of popu- 
lations across the intervening 600 miles, or has 
diverged significantly, producing a high per- 
centage of endemic species. 
1 Zoology Department, University of Auckland, 
New Zealand, and Division of Invertebrate Zoology, 
Peabody Museum of Natural History, Yale University. 
Manuscript received September 6, 1963. 
In order to generalize about the relation- 
ships of the Palau Islands sponge fauna it is 
necessary to know something of the faunas of 
contiguous areas. Two main regions have con- 
tributed to the Palauan fauna, the Indo-Malayan 
and the New Guinea-northern Australian. The 
sponge fauna of the Indo-Malayan region is 
known chiefly from the works of Thiele ( 1898, 
1900, 1903), Lindgren (1897), Kieschnick 
(1898), Topsent (1897), Hentschel (1912), 
Wilson (1925), de Laubenfels (1935), and 
Levi (1961). 
Islands to the east of the Palaus are rela- 
tively unknown in respect to their sponge 
fauna. With the exception of Hawaii the lit- 
erature is restricted to Kirkpatrick (1900) for 
Christmas Island; and de Laubenfels (1949) 
for Yap, (1955) for Onotoa, and (1954) for 
the Marshall Islands, Caroline Islands, and the 
Marianas. 
Our knowledge of the New Guinea and 
northern Australian fauna stems from the work 
of Ridley (1884) and Burton (1934). 
Many of the references cited above are very 
old and require extensive revision; this, added 
to the obvious incompleteness of the faunal pic- 
ture they present of their respective areas, re- 
stricts the zoogeographic comparisons that can 
be made. In view of the unreliability of the 
literature, the statements made here with re- 
spect to the Palau Islands are based solely on 
the specimens examined in the course of this 
investigation, and draw on de Laubenfels’ work 
only where this has been verified. It will be 
possible to give a more detailed analysis when 
collections from Ifaluk, Kapingamarangi, the 
Philippines, and Hawaii have been fully studied. 
Fifty species are described in this report; of 
this number nine are new. A total of 14 species 
is endemic to the Palau Islands; seven species 
are known only from the Palaus eastward, in 
the case of Xestospongia exigua eastward to 
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