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Containing group: Histioteuthidae

Introduction

H. bonnellii is the type species of the genus. It reaches a rather large size (33 cm ML, 119 cm total length) for a histioteuthid. Its uneven distribution and variation in characters normally considered stable within species suggests that a number of separate populations exist.

Diagnosis

A Histioteuthis ...

• with three series of photophores on arms III.
• with three large, dark, round photophores on the ventrolateral corner of the head.

Characteristics

1. Buccal crown
   1. Buccal crown with 6 buccal supports.
2. Photophores
   1. Compound photophores number 17 (rarely 16 or 18) around right eye.
   2. 3 large, round, dark photophores on left posterior margin of ventral surface of head (see drawing to the right).
      image info image info

      Figure. Ventral view of left-ventral region of head of H. bonnellii. Left - 42 mm ML, female, 43°N, 61°W. Drawing from Voss, et al. (1998). Right - Photograph by M. Vecchione.
      

Comments

More details of the description can be found here.

Species of the bonnellii-group are distinguished by the following characteristics:

1. Photophores
   1. Single, elongate, simple photophore at end of each arm I-III.
   2. Type 1b head photophore pattern (needs confirmation from H. macrohista).
   3. Two or three large, round photophores on left posteroventral margin of head.
   4. Compound photophores of large, uniform size on anterior half of ventral mantle.
   5. Arms IV with 3 longitudinal series on arm base and without separated group of compound photophores at arm tips.
2. Web
   1. Deep inner web between arms I-III (>50% of length of longest arm; no other species have webs > 30%).
3. Buccal membrane attachments
   1. Multiple attachments of the fourth (ventral) supports of the buccal crown (i.e., 1 each to sides of arms IV and to junctures of web segments from arms III and IV).
4. Tubercles
   1. Absent

This species is most easily separated from its close relative, H. macrohista by the presence of 6, rather than 7, supports in the buccal crown, 17 rather than 16 photophores on the right eyelid (numbers rarely overlap) and the presence of 3 rather than 2 conspicuous, dark, round photophores on the posteroventral margin of the head on the left side. An additional difference is the manner that the inner webs between the third arms join those of the ventral arms. In H. bonnellii the two junctions nearly form a common junction, while in H. macrohista they are widely separated. Voss, et al. (1998) also show differences in sperm mass length and number of loops in the ejaculatory apparatus of the spermatophores, in the number of gill lamellae as well as the usual presence of an elongate, simple but relatively small photophore on the tips of arms IV.

The above description, comparisons and comments, with the exception of the head photophore pattern, is taken from Voss, et al., 1998.

We list the head photophore pattern for the bonnellii-group as Type 1b. We have only examined H. bonnellii, however, drawings in Voss (1969) suggest that H. macrohista also has this pattern.

Nomenclature

Clarke (1980) described a subspecies, H. b. corpuscula, from whale stomach taken in the South Atlantic (type locality - 30°S,31°E). Voss et al., 1998, in an extensive study of the species, found that the characters Clarke used to separate the subspecies were insufficient. They suggest, however, that different populations of the species may exist based on differences in spermatophore structure. If this proves correct, they suggest that the Atlantic subtropical form could be identified to H. b. corpuscula.

Life History

Largest mature female known is 33 cm ML from subarctic waters and carried mature eggs of 2.3 mm diameter (Kristensen, 1980). Females may mature at 70 mm ML in tropical waters. Mature males are known from 50-330 mm ML depending somewhat on latitude (Voss, et al., 1998). image info

Figure. Dorsal view of a young (8.7 mm ML) H. bonnellii, 37° 58'N, 27° 39' W. Drawing from Voss, 1969 (Fig. 35c).

Distribution

Geographical distribution

Type locality: Mediterranean Sea, off Nice.

H. bonnellii is widely but unevenly distributed in the Atlantic. It is absent from northern subropical and western tropical waters and probably other areas. It is found in a narrow band of subtropical waters that includes areas off Argentina, South Africa and the region between Australia and New Zealand (Voss et al., 1998). Voss et al. (1998) suggest that the species is absent from oligotrophic waters of the world's oceans and that three populations of this species may exist in the Atlantic ocean (i.e., Southwest Atlantic, Eastern Tropical Atlantic, Northwest Atlantic) based on differences in the structure of the spermatophores. image info

Figure. Distribution chart of H. bonnellii, modified from Voss, et al., 1998.