Overview

Brief Summary

Introduction

This Idiosepiidae contains the smallest species within the Decapoda. Males in some species mature at lengths of 6 mm ML and females at 8 mm ML (Nesis, 1982/7). These cephalopods are elongate but have a rounded posterior mantle and separate fins. A unique attachment organ is present on the dorsal surface of the mantle which is used for attaching the animal to seaweed. They are found in shallow water in the Indo-West Pacific.

Brief diagnosis:

A decapodiform ...

  • with an adhesive organ on the dorsal surface of the mantle.

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Comprehensive Description

Nomenclature

A list of all nominal genera and species in the Idiosepiidae can be found here. The list includes the current status and type species of all genera, the current status, type repository and type locality of all species and all pertinent references.

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Characteristics

  1. Arms
    1. Both arms IV hectocotylized.

      Figure. Oral view of hectocotylized arms IV of Idiosepius pygmaeus, 18 mm ML, off Philippines. Drawing from Voss (1963).

    2. Arms with suckers in two series.
    3. Arm and tentacle suckers without circularis muscles.

  2. Tentacles
    1. Tentacles without carpal (= proximal) locking-apparatus.
    2. Tentacular clubs with suckers in 2 - 4 series.

  3. Head
    1. Head with tentacle pockets.
    2. Eyes with corneas.

  4. Funnel
    1. Funnel without lateral funnel adductors.

  5. Mantle
    1. Adhesive organ on dorsal surface (see title drawing).

      Figure. Top - Dorsal view of Idiosepius sp., preserved, with an enlargement of a portion of the dorsal adhesive organ showing the glandular (white reflection) epithelium. 12 mm ML, mature female, 05°27'S, 134°27'E. Photograph by R. Young. Bottom -Side view of Idiosepius paradoxus in an aquarium attached by its adhesive organ to a blade of seagrass. Photograph by Takashi Kasugai, Port of Nagoya Public Aquarium.

    2. Mantle not fused to head in nuchal region, but nuchal cartilage absent.
    3. Mantle locking-apparatus does not reach anterior mantle margin.

  6. Fins
    1. Fins completely separate; with posterior lobes.

  7. Shell
    1. Shell a delicate gladius not reaching anterior or posterior ends of mantle.

  8. Viscera
    1. Right oviduct present but not functional.
    2. Accessory nidamental glands present.
    3. Gills without branchial canals.

  9. Eggs
    1. Eggs attach to substrate in flat masses.

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Life History and Behavior

Life Cycle

Life History

I. paradoxus spawns repeatedly in captivity. A single individual may lay as many as 42 batches over a 70 day period (Kasugai, 2006).


Figure. Side view of a spawning female I. paradoxus in an aquarium. The squid is attached to a blade of seagrass by its adhesive organ and is attaching its eggs to the underside of the same blade. Another I. paradoxus is swimming nearby, presumably a male. Photograph by Takashi Kasugai.

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Evolution and Systematics

Evolution

Classification

Idiosepiidae contains the sole genus Idiosepius Steenstrup, 1881, a tiny (< 1 cm) cephalopod of uncertain phylogenetic placement, sometimes included in Sepiida e.g. Nesis, 1987).
Creative Commons Attribution 3.0 (CC BY 3.0)

© WoRMS for SMEBD

Source: World Register of Marine Species

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
                                        
Specimen Records:85Public Records:85
Specimens with Sequences:85Public Species:2
Specimens with Barcodes:85Public BINs:9
Species:2         
Species With Barcodes:2         
          
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Barcode data

Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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