Overview

Brief Summary

Introduction

A. heminuchalis is a small sized species, less than 40mm DML, found in the tropical Pacific. It is very similar to A. siedleckyi from off South Africa and may prove to be a junior synonym of the latter. It is characterized by its proportionally short, robust mantle and a photophore arrangement on the ventral head and mantle in which large photophores have a space surrounding each organ.

Brief diagnosis:

An Abralia (Heterabralia) with ...

  • anterior ocular photophore comparable in size to largest of 3 medial ocular photophores but much smaller than posterior ocular photophore.
  • irregular photophore series on mid-region of arms IV.

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Comprehensive Description

Characteristics

  1. Tentacle clubs
    1. Two or three hooks on ventral side.
    2. Two rows of large suckers on dorsal side of manus.

    Figure. Oral view of the tentacular club of A. heminuchalis. Drawing from Burgess (1991, p. 121, Fig. 2J)

  2. Hectocotylus
    1. Left ventral arm of male hectocotylized.
    2. Hectocotylus with two different sized off-set flaps: an elongate, proximal flap on ventral margin and much shorter, distal flap on dorsal margin.

    Figure. Oral view of the distal portion of the hectocotylus of A. heminuchalis. Drawing from Burgess (1991, p. 121, Fig. 2I).

  3. Eye Photophores
    1. Five, complex organs: two terminal opaque organs and three intermediate silvery organs. Posterior opaque organ much larger than others; anterior opaque photophore about the same size as the largest intermediate organ.

      Figure. Ventral view of the ocular photophores of A. heminuchalis, anterior is at left. Top - Drawing from Burgess (1991, p. 121, Fig. 2B). Bottom - Photograph of a damaged, preserved eye. Note the pale color of the two terminal photophores and the orange color of the three medial photophores. Photograph by R. Young.

  4. Integumental Photophores
    1. Arms IV with scattered photophores between the two photophore series (the series on the edge of the lateral memberane constitutes a third series).
    2. Ventral mantle and head with scattered arrangement of integumental organs.
    3. Large organs each surrounded by space lacking photophores (black arrows in photograph). Their appearance (which is poorly defined in the photograph) varies depending on the contraction state of nearby chromatophores.
    4. Scattered, small photophores on midregion of arms IV between medial and lateral arm photophore series (white arrow in photograph). These photophores apprear at about 25 mm ML and are absent in A. andamanica and A. trigonura.

      Figure. Ventral view of the head, posterior region of arms IV and anterior region of mantle of A. heminuchalis, 35 mm ML, equatorial pacific, mature male. Note the small photophores present in the mid-region of arms IV (white arrow). Note, also, the large photophores surrounded by a ring of smaller photophores, two of which are indicted by the black arrows. Photograph by R. Young.

  5. Reproductive structures
    1. Posterior region of nuchal cartilage replaced by part of the receptacle for spermatangia in females.
    2. Figure. Dorsal (top) and dorsolateral (bottom) views of the receptacle for spermatangia in female A. heminuchalis. Anterior is right. Note that the posterior region of the nuchal cartilage is covered by the organ and that permatangia attach to ruguose areas (not a deep pit) on posterior portion of nuchal cartilage and gladius. Mantle, gladius and attachment area folded posteriorly. Drawing from Burgess (1991, p. 121, Fig. 2K). Photograph by R. Young.

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Distribution

Geographical distribution

Distribution is the tropical Pacific from 5°N, 98°W (Okutani, 1974) to waters near Palau Isl. (6°N, 135°E) (Hidaka and Kubodera, 2000) and 16°S (Burgess, 1991) to 12°N (Hidaka and Kubodera, 2000).

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Physical Description

Type Information

Paratype for Abralia (Heterabralia) heminuchalis Burgess, 1992
Catalog Number: USNM 729719
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: male; female;;; ;; larvae
Preparation: Isopropyl Alcohol
Year Collected: 1958
Locality: Line Islands, Kiribati, South Pacific Ocean
Depth (m): 576
Vessel: Hugh M. Smith R/V
  • Paratype: Burgess, L. A. 1992. Bull. Mar. Sci. 49(1-2): 113-136.
Creative Commons Attribution 3.0 (CC BY 3.0)

© Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology

Source: National Museum of Natural History Collections

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Holotype for Abralia (Heterabralia) heminuchalis Burgess, 1992
Catalog Number: USNM 729683
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: female;
Preparation: Isopropyl Alcohol
Year Collected: 1958
Locality: Line Islands, Kiribati, South Pacific Ocean
Depth (m): 576
Vessel: Hugh M. Smith R/V
  • Holotype: Burgess, L. A. 1992. Bull. Mar. Sci. 49(1-2): 113-136.
Creative Commons Attribution 3.0 (CC BY 3.0)

© Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology

Source: National Museum of Natural History Collections

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Ecology

Habitat

Depth range based on 59 specimens in 1 taxon.
Water temperature and chemistry ranges based on 59 samples.

Environmental ranges
  Depth range (m): 20 - 622
  Temperature range (°C): 7.076 - 27.393
  Nitrate (umol/L): 0.253 - 40.784
  Salinity (PPS): 34.444 - 36.049
  Oxygen (ml/l): 0.678 - 5.073
  Phosphate (umol/l): 0.164 - 2.956
  Silicate (umol/l): 1.014 - 55.696

Graphical representation

Depth range (m): 20 - 622

Temperature range (°C): 7.076 - 27.393

Nitrate (umol/L): 0.253 - 40.784

Salinity (PPS): 34.444 - 36.049

Oxygen (ml/l): 0.678 - 5.073

Phosphate (umol/l): 0.164 - 2.956

Silicate (umol/l): 1.014 - 55.696
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Wikipedia

Abralia heminuchalis

Abralia heminuchalis is a species of enoploteuthid cephalopod native to the equatorial regions of the Pacific Ocean. It may be a junior synonym of A. siedleckyi. Females are larger (28–37 mm mantle length) than males (25–32 mm mantle length). Oocytes in mature females can reach 1.25 mm in length. Male spermatophores are relatively small at 3.6–4.0 mm in length.

References[edit]

  1. ^ Barratt, I. & Allcock, L. (2014). "Abralia heminuchalis". IUCN Red List of Threatened Species. Version 2014.1. International Union for Conservation of Nature. Retrieved 18 June 2014. 
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

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