Pacific Science Volume 24, Number 1, 1970
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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.
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ItemA Sulfur Lava Flow on Mauna Loa(University of Hawai'i Press, 1970-01)The presence of sulfur crystals formed by condensation around fumarolic vents is a common and widely observed phenomenon in volcanic regions. The flowage of sulfur in a molten state is very rare, however, and is sufficiently unique to suggest a permanent record of its occurrence.
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ItemA New Engraulid Fish, Anchoa walkeri, from the Eastern Pacific Ocean, with a Note on the Validity of Anchoa schultzi Hildebrand(University of Hawai'i Press, 1970-01)With the adition of Anchoa walkeri, the eastern Pacific members of the family Engraulidae are represented by over 30 recognizable species. They are fairly common along both coasts of the Americas in temperate and tropical waters and they have played an important role as a forage fish and as a bait fish by the tuna fishing industry. Since bottom trawling and beach seining methods often yield large numbers of the various species of anchovies, specimens are fairly well represented in museum collections such as that of the University of California, Los Angeles.
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ItemNew Species of Peperomia (Piperaceae) and Dendrocnide (Urticaceae) from Rotuma Island, Pacific Ocean. Pacific Plant Studies 19(University of Hawai'i Press, 1970-01)Rotuma Island lies in the central Pacific Ocean, at the meeting point of Polynesia, Micronesia, and Melanesia. Its botany had not been explored until the writer made an expedition to it in 1938. Two new species peculiar to it are here announced.
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ItemSystematic Anatomy of the Red Algal Genus Rhodopeltis(University of Hawai'i Press, 1970-01)At present five species are known in the genus Rhodopeltis, which belongs to the red algal order, Cryptonemiales. Of these, Rhodopeltis australis was first found in Australia, and the other four species, R. borealis, R. setchelliae, R. liagoroides, and R. gracilis all grow in the southern islands of Japan and were described by Yamada.
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ItemA New Species of Dulichia (Amphipoda, Podoceridae) Commensal with a Sea Urchin(University of Hawai'i Press, 1970-01)
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ItemNotes and Bibliography on the Larvae of Xanthid Crabs(University of Hawai'i Press, 1970-01)Decapod systematics have rarely attempted to draw supporting evidence from the larval phase (Gurney, 1942, p. 12). However, It is generally recognized that phylogenetic conclusions drawn from larval stages alone without reference to adult systematics can be very misleading, but the two approaches considered together can be of value. This is especially so in the decapod Crustacea, both in the separation of closely allied species and in the assessment of relationships at all levels. Nevertheless, there are several exceptions to this generalization , more especially in the Caridea where some closely related genera possess widely differing larvae (Gurney, 1942, p. 15) .
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ItemSystematics of Indo-Pacific Philippia (Psilaxis), Architectonicid Gastropods with Eggs and Young in the Umbilicus(University of Hawai'i Press, 1970-01)The subgenus Psilaxis Woodring is distinguished from Philippia Gray, s.s., on the basis of differences in the shells, jaws, opercula, and doubtfully radulae. Only two species of Psilaxis, differing mainly in three protoconch characters, are recognized in the Indo-Pacific. Philippia (Psilaxis) radiata (Roding), with the generally smaller protoconch, is the most abundant and widespread species, ranging from South Africa and the Red Sea east to the Marquesas and the Hawaiian Islands ; it is thus both tropical and subtropical. Philippia (Psilaxis) oxytropis A. Adams has a larger protoconch and a disjunct range, being known only from the subtropical western and central Pacific Ocean-including Japan, the Hawaiian Islands, and New Zealand but excluding latitudes between 20 ° Nand 20 ° S. Young postlarval P. oxytropis live in the umbilicus of the adult shells, and in P. radiata one egg mass has been found in an umbilicus. Nevertheless it is concluded from the small egg size of P. radiata (average diameter 63μ) that both species have a long pelagic larval stage. Philippia hybrida (Linn.) is a Mediterranean species in the subgenus Philippia, s.s., and P. layardi A. Adams is a synonym of P. radiata. In Marqu esan P. radiata there is a noteworthy increase and bimodality in protoconch size that are attributed tentatively (with no chromosomal evidence) to polyploidy. Polyploidy perhaps also is involved in the origin of species of Philipp ia and in the origin of Psilaxis from Philippia, s.s. By the Miocene, Psilaxis seems to have displaced Philippia, s.s., from most areas except peripherally in the subtropics. The pyramidellid-like egg capsules of architectonicids are described for the first time, and the larvae are also opisthobranch-like. Philippia has a cuticularized esophageal tube and radular teeth similar ( analogous? ) to those in the Epitoniidae.
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ItemThe Feeding, Larval Dispersal, and Metamorphosis of Philippia (Gastropoda: Architectonicidae)(University of Hawai'i Press, 1970-01)In the Hawaiian Islands , Philippia (Psilaxis) radiata (Reding) lives in sand or rubble near the hermatypic stony coral Porites lobata Dana, and emerges to feed at night on the polyps, Other species of Philippia (Psilaxis) probably have the same mode of life with corals. Philippia (Psilaxis) veliger larvae are abundant in tropical and subtropical oceanic plankton distant from any potential shallow-water hosts, and are dispersed great distances by near-surface currents. Duration of the pelagic larval stage is between several weeks and 6 months or longer. Metamorphosis, involving loss of the 4-lobed velum, initial growth of the teleoconch, and other changes, can precede contact with a host and is induced by capture from the plankton. Newly settled Philippia quickly attain a stage of arrested growth and can remain alive without feeding for several months . At this stage the postlarvae presumably crawl in search of hosts, and failure to find hosts doubtless causes the high mortality observed. Experiments at Woods Hole, Massachusetts, with newly metamorphosed P. (Psilaxis) krebsii (March), obtained as larvae from plankton in the Sargasso Sea, together with the ahermatypic coral Astrangia danae Agassiz, reveal physical problems for Philippia in assuming the adult mode of life with other corals. Young Philippia showed no ability to detect Astrangia except by touch. Young Philippia lacked immuni ty to Astrangia nematocysts but were not seriously injured by them . The young gastropods are, however, subject to predation by this coral. Most contacts with the living tissues of Astrangia caused a Philippia to be promptly drawn through the mouth and ultimately digested. The large protoconchs of Psilaxis would preclude their being swallowed by hermatypic corals such as Porites, with polyps smaller than those of Astrangia. Proboscis eversion and feeding were not observed in young P. krebsii.
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ItemReview of the Predators and Parasites of Stony Corals, with Special Reference to Symbiotic Prosobranch Gastropods(University of Hawai'i Press, 1970-01)Predators and parasites on the living tissues of stony (scleractinian) corals include bony and cartilaginous fishes, asteroids, crustaceans (cyclopoid copepods, cirripedes, and brachyuran crabs) , polychaetes, and gastropods (prosobranchs and nudibranchs). These are all facultative predators except the crustaceans and gastropods that are obligately associated (symbiotic) with and feed on their coral hosts. Such symbionts are known in four unrelated families of crustaceans (Xarifiidae, Asterocheridae, Balanidae, and Xanthidae) and four unr elated families of prosobranch gastropods (Architectonicidae, Epitoniidae, Ovulidae, and Coralliophilidae) . A fifth prosobranch family includes frequent but not obligate coral associates that are coral- and possibly also mollusk-feeders (Muricidae [Drupa, subgenus Drupella]). The eolid nudibranch genus Phestilla (Tergipedidae) includes the only so far identified opisthobranchs definitely symbiotic with corals. Most of the crustacean and molluscan symbionts live with hermatypic corals in the Indo-Pacific. Specificity to particular genera or families of corals is low, but the bright yellow, orange, or pink phases (species?) of the dendrophylliid ahermatypic coral Tubastraea are host to similarly colored prosobranchs C Epitonitlm" ) and a nudibranch (Phestilla melanobrachia) . Adapt ations for feeding on coelenterates are various, but in unrelated gastropod families similar specializations occur (cuticularized esophaguses and proboscises, ptenoglossate-like radular teeth, and total loss of radulae) . The most specialized of the coral-dwelling prosobranchs are the coralliophilids ( including Magiltus), parasites without radulae living both on and in coelenterates.
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ItemThe Present Status of the Birds of Hawaii(University of Hawai'i Press, 1970-01)The great expanses of open ocean that separate the Hawaiian Islands from the major continental land masses of North America and Asia resulted in the evolution of a number of unique landbirds. Unfortunately, a higher percentage of species of birds have become extinct in Hawaii than in any other region of the world. Approximately 40 percent of the endemic Hawaiian birds are believed to be extinct, and 25 of the 60 birds in the 1968 list of "Rare and Endangered Birds of the United States" are Hawaiian ("Rare and Endangered Fish and Wildlife of the United States, 1968 edition," Bureau of Sport Fisheries and Wildlife, Washington, D. C.). Most of the native birds of Oahu have long been extinct, and few native landbirds are to be found on any of the main islands below 3,000 feet elevation. Three general groups of birds are found in Hawaii today: endemic, indigenous, and introduced.