Stigmatoteuthis hoylei (Goodrich 1896)

Introduction

Species of Stigmatoteuthis are distinctive in having very long arms relative to the ML and paired secondary reproductive organs (terminal organ (=penis), spermatophore gland complex, Needham's sac). Damaged individuals of Stigmatoteuthis can often be recognized by the sawtooth arrangement of photophores in the Basal Series of the head. At present differences between Atlantic and Indo-Pacific species are poorly defined and depend on mature males. Identification, therefore, rests primarily on location of capture.

Diagnosis

A Stigmatoteuthis ...

• with a tropical Indo-Pacific habitat.

Characteristics

1. Head
   
   1. Beaks: Descriptions can be found here: Lower beak; upper beak.
      
      
2. Reproductive system
   1. Ejaculatory apparatus of spermatophore with numerous loops.
   2. Sperm mass about 60% of SpL.
   3. Hectocotylus with multiple sucker series in midportion.
   4. Hectocotylus without papillated skin on ventral surface.

Comments

Members of Stigmatoteuthis are easily recognized by the Type 1a photophore pattern of the head which has 3 photophores in the Midline Series and no rogue photophore (see pattern on next page). S. hoylei can be most easily separated from S. dofleini by the complex looping found in the ejaculatory apparatus of the spermatophore. It is most easily separated from S. arcturi by the presence on the hectocotylus of multiple sucker series, enlarged distal suckers and the absence of tubercules on this structue. If mature males are not available, separation is based on habitat.

Species Stigmatoteuthis are characterized by the presence of:

1. Tentacular clubs
   1. Medial suckers of tentacular clubs greatly enlarged, more than 4X diameter of minute marginal suckers.
2. Photophores
   1. Type 1a pattern on head (e.g., 3 Midline Series photophores, 3 Basal Arm IV Row photophores and no rogue photophore).
   2. Basal Row on head with 8 photophores and 3 sawteeth.
   3. Right Basal Series on head present.
   4. Ends of arms IV without separate group of compound photophores.
   5. Compound photophores of large, uniform size and evenly spaced on anterior half of ventral mantle.
3. Tubercles
   1. Absent.
4. Mantle
   1. Skin of the mantle and elsewhere with dermal warts beneath outer epithelium in large squid.
5. Viscera
   1. Mail genitalia paired.

With the exception of the analysis of the head photophores, the above information is from Voss (1969) and Voss, et al. (1998).

Nomenclature

All world-wide specimens in Stigmatoteuthis were considered by Voss (1969) to belong to H. dofleini. Voss et al. (1992) after examining the type of Histiopsis hoylei Goodrich, 1896, placed all known specimens in the synonomy of this earlier named species, Histioteuthis hoylei (Goodrich, 1896). Voss et al., (1998) recognized that the Atlantic form was diffferent and should be called H. arcturi (Robson, 1948). They based the separation primarily on striking differences in the spermatophore and hectocotylus of the mature male. Unfortunately few mature specimens were known for comparisons. The males that represented H. hoylei came from north temperate waters off California and Japan. We have examined specimens from off Hawaii and found they have spermatophores with the distinctive ejaculatory apparatus of H. arcturi from the Atlantic but differ in some features of the hectocotylus. Therefore, the Pacific forms divide into a temperate North Pacific species which carries the name, H. dofleini, and a more southern species, H. hoylei. Instead of placing H. hoylei and H. arcturi in synonomy, we maintain the separation of these species as Voss et al., (1998) list other separating characters such as features of the gladius, beak, web and arm lengths that are not all related to maturity and are based on squids from a wider geographical range. We place all members of the hoylei-group into the genus Stigmatoteuthis.

In this clade of histioteuthids with bilaterally paired male secondary sexual organs, the first species described was Histiopsis hoylei Goodrich 1896. However, the type species of the nominal genus Histiopsis is H. atlantica, which has unpaired male organs and Histiopsis was subsequently placed in the synonomy of Histioteuthis (Voss,1969). Pfeffer (1900) described the genus Stigmatoteuthis, with type species S. hoylei (Goodrich 1896) by monotypy. (This is not the same species as Meleagroteuthis hoylei Pfeffer, 1900 which, according to Nesis, 1987, is a synonym of Histioteuthis meleagroteuthis.) Therefore Stigmatoteuthis Pfeffer 1900 is the valid-genus name designated for a species in this clade.

Life History

Probable paralarvae of this species are shown on the Histioteuthidae page.

Distribution

Vertical distribution

During a study of vertical distribution off Hawaii, S. hoylei was captured at depths of 375-850 m during the day with most captures at depths greater than 500 m. At night captures were made at depths from 100-500 m. During both the day and night there is a size/depth trend with larger squid tending to be caught at greater depths.

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

Figure. Vertical distribution chart of S. hoylei, Hawaiian waters. Modified from Young (1978). Captures were made with both open and opening/closing trawls. Bars - Fishing depth-range of opening/closing trawl. Circle - Modal fishing depth for either trawl. Square - Midpoint of trawl where no modal depth was available. Blue color - Night captures. Yellow color - Day captures. Red dots - Apparent deep night captures assummed to be contaminants as the open net passed through shallower depths.

Geographical distribution

Type locality:Andaman Sea, Indian Ocean.

S. hoylei has been reported throughout much of the tropical Pacific and tropical Indian Oceans (Voss, et al., 1998). When Voss et al., 1998, described the distribution of this species they believed all Pacific and Indian Ocean specimens to belong to S. hoylei. We have assummed that all of their records from off the west coast of the United States and the east coasts of Japan and Russia belong to S. dofleini and these the records have been eliminated from the chart presented here.

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

Figure. Geographical distribution chart for S. hoylei. Modified from Voss, et al. (1998).

References

Voss, N. A. 1969. A monograph of the Cephalopoda of the North Atlantic: The family Histioteuthidae. Bull. Mar. Sci., 19: 713-867.

Voss, N. A., S. J. Stephen and Zh. Dong. 1992. Family Histioteuthidae. Smithson. Contr. Zool., No. 513: 73-91.

Voss, N.A., K. N. Nesis, P. G. Rodhouse. 1998. The cephalopod family Histioteuthidae (Oegopsida): Systematics, biology, and biogeography. Smithson. Contr. Zool., 586(2): 293-372.

Young, R. E. 1978. Vertical distribution and photosensitive vesicles of pelagic cephalopods from Hawaiian waters. Fish. Bull., 76: 583-615.