Echinoid larvae from the northeast Pacific (with a key and comment on an unusual type of planktotrophic development)

1979 ◽  
Vol 57 (3) ◽  
pp. 610-616 ◽  
Author(s):  
Richard R. Strathmann

Larvae of all seven species of echinoids occurring in coastal waters from southern British Columbia to central California have been reared through metamorphosis. Larvae of Dendraster excentricus, Brisaster latifrons, and Strongylocentrotus franciscanus can be distinguished from all others by skeletal traits alone. Living larvae of Strongylocentrotus droebachiensis and Strongylocentrotus purpuratus can be distinguished from all others by color of pigment spots combined with skeletal differences. Larvae of Allocentrotus fragilis and Strongylocentrotus pallidus have similar skeletons and pigment spots of the same color, so it is difficult to identify specimens even if they are alive. A key is provided for identification of echinoplutei.Development of Brisaster latifrons is similar to that of Brisaster fragilis in the Atlantic. The development is unusual for echinoderms in that large eggs develop into large feeding larvae with a long pelagic period. Moreover, the juveniles formed at metamorphosis have about the same diameter as juveniles of echinoids with much smaller eggs but similar pelagic periods.

Zootaxa ◽  
2019 ◽  
Vol 4700 (1) ◽  
pp. 1-29
Author(s):  
B. OTT ◽  
H. M. REISWIG ◽  
N. McDANIEL ◽  
R. HARBO

Collections of sponges by the late Dr. William C. Austin and the authors (N. McDaniel, R. Harbo and B. Ott) provided material for descriptions of new species from two genera of Poecilosclerida for shallow waters of Southern British Columbia, Canada and Northern Washington, USA: Lissodendoryx and Myxilla. There have been no new species of these two genera described for the Northeast Pacific since Laubenfels’ work in central California (Laubenfels 1930, 1932) and Lambe’s reports in 1893 to 1895 for Geological Survey of Canada sponge collections from British Columbia, Canada to the Bering Sea. We describe three new species of Lissodendoryx (Lissodendoryx) (Demospongiae, Poecilosclerida, Coelosphaeridae) and one new species of Myxilla (Myxilla) (Demospongiae, Poecilosclerida, Myxillidae): L. (L.) barkleyensis n. sp., L. (L.) littoralis n. sp., L. (L.) toxaraphida n. sp. and M. (M.) austini n. sp. Lissodendoryx (L.) barkleyensis n. sp. is cave-dwelling, has acanthostyles 112–260 µm, tornotes 107–177 µm, arcuate isochelas 8–28 µm and two sizes of sigmas 18–29, 26–55 µm. Lissodendoryx (L.) littoralis n. sp. fistulate habitus is adapted to muddy substrates similar to some Polymastia species also found commonly in the Northeast Pacific. It has subtylostyles 185–336 µm, tylotes 112–229 µm, arcuate isochelas 11–23 µm, and sigmas 30–75 µm. Lissodendoryx (L.) toxaraphida n. sp. is the only described Lissodendoryx species with raphides shaped like toxas. It has acanthostyles 140–286 µm, tornotes 143–195µm, arcuate isochelas 18–34 µm and toxiform raphides 65–156 µm. Myxilla (M.) austini n. sp. has a fistulate habitus and both tornote and tylote megascleres. It appears to be tolerant of low oxygen environments. Myxilla (M.) austini n. sp. has smooth to sparsely spined styles 193–353 µm, tylotes 153–221 µm, tornotes 174–260 µm, two sizes of anchorate isochelas 13–27, 42–81 µm, and two sizes of sigmas 13–47, 33–78 µm. All specimens were collected from shallow water (intertidal to 25 m). 


2011 ◽  
Author(s):  
Thomas A. Rago ◽  
Reiko Michisaki ◽  
Baldo Marinovic ◽  
Marguerite Blum

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Nur Arafeh-Dalmau ◽  
Kyle C. Cavanaugh ◽  
Hugh P. Possingham ◽  
Adrian Munguia-Vega ◽  
Gabriela Montaño-Moctezuma ◽  
...  

AbstractKelp forests are globally important and highly productive ecosystems, yet their persistence and protection in the face of climate change and human activity are poorly known. Here, we present a 35-year time series of high-resolution satellite imagery that maps the distribution and persistence of giant kelp (Macrocystis pyrifera) forests along ten degrees of latitude in the Northeast Pacific Ocean. We find that although 7.7% of giant kelp is protected by marine reserves, when accounting for persistence only 4% of kelp is present and protected. Protection of giant kelp decreases southerly from 20.9% in Central California, USA, to less than 1% in Baja California, Mexico, which likely exacerbates kelp vulnerability to marine heatwaves in Baja California. We suggest that a two-fold increase in the area of kelp protected by marine reserves is needed to fully protect persistent kelp forests and that conservation of climate-refugia in Baja California should be a priority.


1966 ◽  
Vol 44 (5) ◽  
pp. 839-849 ◽  
Author(s):  
C. Berkeley

Twenty-five species of Polychaeta recently collected off the coast of British Columbia are discussed. Most were taken in waters of considerable depth off the west coast of Vancouver Island. Sixteen are new to British Columbia. Most of these are known from farther south on the west coast of North America, but some from much shallower depths than those from which they are now recorded; two of them are new to the northeast Pacific; one is a new subspecies. The other nine have been previously known from British Columbia, but they are now recorded from much greater depths than hitherto, or in new geographical locations.


Abstract.—We report patterns of infestation with motile salmon lice, <em>Lepeophtheirus salmonis</em>, on Pacific salmon collected with a surface trawl in coastal waters of Oregon, Washington, British Columbia, and Alaska during 2002 and 2003. Salmon lice were observed on all salmon species examined and in all areas surveyed. The prevalence and abundance of lice infestation varied significantly among species, size-classes, seasons, regions, and years, with larger salmon being consistently more heavily infested than small salmon. The number of lice infesting the small size-class (100–400 mm) of salmon rarely exceeded 5 lice per fish with a mean abundance generally below 0.2 lice per fish. Lice prevalence and, to a lesser extent, lice abundance increased over time in small fish, with lower values during spring and higher values in the following winter, and continued to increase in larger and older fish. There were no apparent effects of water temperature on lice infestation in Pacific salmon. This study suggested that salmon infested with lice remained in coastal waters throughout the year. We suggest that lice on salmon that overwinter in coastal waters will contribute to a pool of infective copepodids in these habitats.


2006 ◽  
Vol 120 (2) ◽  
pp. 179
Author(s):  
George W. Douglas ◽  
Jenifer L. Penny

In Canada, the Small-flowered Tonella, Tonella tenella, is restricted to the west side of Saltspring Island in the Gulf Islands of southwestern British Columbia. This population represents the northern limits of the species which is disjunct from its main range in southern Washington (Columbia River gorge), through Oregon to central California. In British Columbia, Tonella tenella is associated with rock outcrops and dry, steep, sparsely forested talus slopes at elevations of 50 to 300 m. The population on Saltspring Island is on private property and not directly imperilled at this time. There is, however, a potential for housing development in the future on this waterfront site, thus the authors consider the species endangered.


2020 ◽  
Vol 150 ◽  
pp. 110691 ◽  
Author(s):  
Sophia C. Johannessen ◽  
Charles W. Greer ◽  
Charles G. Hannah ◽  
Thomas L. King ◽  
Kenneth Lee ◽  
...  

Paleobiology ◽  
1991 ◽  
Vol 17 (4) ◽  
pp. 325-339 ◽  
Author(s):  
Steven C. Beadle

Under favorable circumstances, biogeographic and biostratigraphic data can be combined to identify accurately the time and place of origin of a given taxon, and to reconstruct the pattern of its subsequent radiation. This study considers the dendrasterid sand dollars, which are abundant today along the Pacific Coast of North America. The Neogene sand dollar record in this region is particularly good; in fact, sand dollars have traditionally been used as provincial index fossils.The dendrasterids originated in central California at the end of the Miocene; the oldest forms are dated at about 6.0–6.5 Ma. They spread south to Baja California during the Pliocene, and then north to Alaska during the Quaternary. This historical pattern is not an artifact of the record; it is consistent with independent paleogeographic evidence. The dendrasterids supplanted an older Mio-Pliocene sand dollar fauna; they are now completely dominant in the temperate coastal waters of the northeastern Pacific. They have reached this position in less than 7 m.y. since their first local appearance. The rapid rise of dendrasterids could be related to their aberrant morphology and behavior; these adaptations allow dendrasterids to suspension-feed, in a manner unique among living echinoids.Dendrasterids are characterized by “eccentric” test morphologies. Even the oldest species are highly eccentric; transitional forms are unknown. The first dendrasterids appear suddenly in the provincial “Jacalitos Stage,” above an unconformity which represents no more than about 1 m.y. They do not occur in the underlying units, although other fossil sand dollars are abundant. The dendrasterids may have arisen rapidly, through a heterochronic change in the development of older, noneccentric forms. Recent ontogenetic studies have documented the feasibility of this process.


2015 ◽  
Vol 96 (1) ◽  
pp. 71-80 ◽  
Author(s):  
G Hanke ◽  
G Gillespie ◽  
K Fong ◽  
J Boutillier ◽  
J Nielsen ◽  
...  

1973 ◽  
Vol 105 (4) ◽  
pp. 605-612 ◽  
Author(s):  
David Evans

AbstractErannis vancouverensis Hulst occurs from northern British Columbia to central California, and has been occasionally reported at infestation levels. The larvae feed on young leaves of several species of deciduous trees; winter is passed in the egg or sometimes in the pupal stage; adults emerge during late autumn or occasionally during winter or early spring; females are wingless. The life stages, including larval instars, are described here in detail. Virus disease and parasitism by tachinid flies help control the species.


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