Iridoteuthis sp. A

Introduction

Two specimens, one mature male and one immature female, both about 23 mm DML, were taken from the stomach of the lancet fish, Alepisaurus ferox off New Caledonia in 2004. The specimens were frozen then fixed in 70% ethanol and are in fairly good condition.

Brief diagnosis:

An Iridoteuthis ...

• with elaborate ventral protective membrane on right arm I in mature males.
  
• without size differentials in some arm suckers between dorsal and ventral series in males.
• without elongate sucker-less stalks on tips of arms III and IV in females.
  

Characteristics

1. Arms
   1. Arm I-III suckers in two series without some being unusually enlarged or reduced in size relative to other suckers on same or adjacent arms.
   2. Males
      1. Arms I in males with complex elaboration of protective membranes, especially that of ventral margin; details unclear.
      2. Males with suckers enlarged, relative to females, on all arms, expecially so on arms I-III (compare photographs below).
      

      Click on an image to view larger version & data in a new window

      
      

      Figure. Oral view of the brachial crown of Iridoteuthis sp. A, mature male, showing enlarged suckers on arms I-III and elongate flag on right arm III (left side of photograph). Photograph by R. Young.

   3. Females
      1. Arms I and III of females with bare tips; extreme tip of arm III further modified but structure not clear..
      2. Females with suckers on arms IV essentially in two size groups: proximal 3/5ths with larger suckers, distal 2/5ths with small suckers.
      

      Click on an image to view larger version & data in a new window

      
      

      Figure. Oral view of the brachial crown of a female Iridoteuthis sp. A. Photograph by R. Young.

   More pictures of the arms can be seen here.
   
   
   4. Head
      
      1. Beaks: Descriptions can be found here: Lower beak; upper beak.
         
         

   Comments

   More details of the description of Iridoteuthis sp. A can be found here. 

   Comparison with Iridoteuthis iris: See the Iridoteuthis page for a table comparing the most obvious differences between the two species.

   The first pair of arms of the male were covered on their oral surface by a membranous substance that may have combined with congealed mucous. At first it appeared to be an artifact consisting of accumulated cuticle that was pealing off much of the animal in conjunction with congealed mucous. Closer inspection suggests that it is, at least in part, an elaboration of the ventral protective membrane.

   Only one of the four clubs examined had not been partially dried and it was strongly coiled. This combined with the unusual structure of the club has made interpretation of its structure difficult and uncertain (see Iridoteuthis sp. A: Description continued).