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Carinaria japonica Okutani 1955

Roger R. Seapy
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Containing group: Carinaria

Introduction

Carinaria japonica is a moderately large species, achieving a maximal body length of 105 mm. The shell is compressed laterally and, when viewed from the side, is triangular in shape with a height to basal length ratio of 0.8-1.0. The keel is low initially, but increases in height with shell growth. The tail is moderately well-developed and has a prominent dorsal crest. The geographical distribution of the species is unique among carinariids; it is limited to the cool, temperate waters of the Transition Zone in the North Pacific Ocean.

Brief Diagnosis

A species of Carinaria with:

Characteristics

  1. Body morphology
    1. Proboscis, trunk and tail regions well-developed
    2. Eye shape triangular in dorsal view
    3. Tail with a prominent dorsal crest (see title photograph)
    4. Larva with a colorless velum except for a dark brown pigment patch at the end of each of the six velar lobes. The body is an overall brown color, although the tentacles are transparent
  2. Shell morphology
    1. Shell triangular in lateral view; ratio of height to basal length = 0.8-1.0. Keel moderately low; keel height increases with basal growth of shell
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      Figure. Left: sketch of Carinaria japonica shell. Right: photograph of stalked visceral nucleus, covered by transparent shell. In the intact shell, the keel height increases with shell growth (as in the sketch on the left), but the keel is often damaged and is much lower (as in the in-situ field photograph on the right). Left © , Right © David Wrobel

  3. Larval morphology
    1. Larva with a colorless velum except for a dark brown pigment patch at the end of each of the six velar lobes. The body is an overall brown color, although the tentacles are transparent
    2. Larval shell transparent and globular in shape

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      Figure. Larval shell of Carinaria japonica from aperture. Shell diameter = 0.6 mm. ©

    3. Right side of larval shell with very small and numerous punctae, arranged in spiral rows on the shell surface. On the shell spire, the second whorl has a prominent spiral ridge, from which narrow, elevated striae radiate
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      Figure. Larval shell of Carinaria japonica from right side. Shell diameter = 0.6 mm. ©

    4. Left side of larval shell with a deep umbilicus. Umbilicus wall has about 18 broad, elevated spiral striae.
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      Figure. Larval shell of Carinaria japonica from left side. Shell diameter = 0.5 mm. ©

    5. At metamorphosis the larval shell consists of 3-2/3 whorls; the adult shell (teleoconch) grows outward from the larval shell aperture and then downward (ventrally). The keel is produced immediately on the juvenile teleoconch
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      Figure. Right side of shell from a juvenile Carinaria japonica. Shell length = 2.3 mm. ©

Distribution

The geographic distribution of Carinaria japonica is restricted to Transition Zone Faunal Province in the North Pacific Ocean (McGowan, 1971; Seapy, 1974). This faunal province consists of a narrow band of surface water at the Subarctic Boundary (located between the Subarctic Pacific and Central Pacific water masses at about latitude 40-41°N), extending eastward from Japanese waters and broadening as it approaches the coast of North America to extend southward as the broad California Current.

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Location of the Transition Zone faunal province (shaded blue) in the North Pacific. The province is separated from the Central North Pacific province by the Subarctic Boundary and its southeasterly extension to Baja California; it merges more broadly with the Subarctic Pacific province to the north. © 2005

Feeding Habits

Among the species of Carinaria, the feeding habits and food preferences of C. japonica have been most thoroughly studied (Seapy, 1980). Thaliaceans (small doliolids and salps), chaetognaths and copepods dominated numerically in the diet. Comparisons of the proportion of each prey species in the diet and available in the plankton indicated preferential feeding on thaliaceans, chaetognaths and mollusks. In contrast crustaceans, and particularly copepods, were non-preferred prey. These prey preference patterns may reflect differences among prey species in their ability to escape capture.

References

McGowan, J. A. 1971. Oceanic biogeography of the Pacific, pp. 3-74. In: The micropaleontology off oceans, B. M. Funnell and W. R. Riedel (eds.). Cambridge: University Press.

Seapy, R. R. 1974. Distribution and abundance of the epipelagic mollusk Carinaria japonica in waters off southern California. Marine Biology 24:243-250.

Seapy, R. R. 1980. Predation by the epipelagic heteropod mollusk Carinaria cristata forma japonica. Marine Biology 60:137-146.

Seapy, R. R. and C. Thiriot-Quievreux. 1994. Veliger larvae of Carinariidae (Mollusca: Heteropoda) from Hawaiian waters. Veliger 37:336-343.

Title Illustrations
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Scientific Name Carinaria japonica
Location off Monterey Bay, California
Specimen Condition Live Specimen
Sex Male
Life Cycle Stage adult
View right side
Copyright © David Wrobel
About This Page


California State University, Fullerton, California, USA

Correspondence regarding this page should be directed to Roger R. Seapy at

Page: Tree of Life Carinaria japonica Okutani 1955. Authored by Roger R. Seapy. The TEXT of this page is licensed under the Creative Commons Attribution License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Seapy, Roger R. . 2008. Carinaria japonica Okutani 1955. Version 29 May 2008. http://tolweb.org/Carinaria_japonica/28750/2008.05.29 in The Tree of Life Web Project, http://tolweb.org/

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