Mastigoteuthis glaukopis Chun, 1908

Introduction

The type description of M. glaukopis is based on a single, small squid (37 mm ML) with one intact tentacle taken off the tropical, east African coast.

Diagnosis

A mastigoteuthid ...

• without integumental photophores but with large eyelid photophore.
• with small club suckers.
• with an Indian Ocean distribution.

Characteristics

1. Arms
1. Arm suckers with blunt, conical teeth around opening, with 5-7 slightly larger teeth distally.
2. Tentacles
1. Tentacle whiplike; club not wider than stalk.
2. Club 70% of tentacle length.
3. Club with indistinct undulating protective membrane.
4. Proximally club with very small, scatteren suckers; club then widens to occupy half the tentacle surface. Distally club extends to leave only about one third of circumference bare with suckers situated close together, nearly touching one another.
5. Club suckers become slightly larger distally except near tip.
image infoimage info

Figure. Tentacular club of M. glaukopis, holotype. Top - View of the twisted club and an aboral view of an enlargement of a portion of the club. Drawings from Chun (1910). Bottom - Slde view of portion of the club. The protective membrane can be detected but little remains of it. Photograph by R. Young

6. Club suckers 0.1 mm in diameter.
7. Club suckers with 10-12 small teeth at approximately regular intervals around inner ring. These teeth are difficult to distinguish from conical knobs on the outer rings.
3. Head
1. Eyes large (15% of ML); occupy most of head.
2. Olfactory organ with short stalk; located on obliquely directed gelatinous pad of neck.
3. Funnel adductors show whitish through shallow funnel groove.
4. Funnel locking-apparatus
1. Funnel locking apparatus with tragus but no antitragus; however, "cartilaginous groove is slightly inflated at the position of the antitragus, so that it gives the indication of an antitragus."
image info

Figure. Ventral view of funnel locking-apparatus of M. glaukopis, holotype. Drawing from Chun (1910).

5. Mantle
1. Tubercules absent from mantle and elsewhere.
6. Fins
1. Fin length about half of ML; shape nearly rhomboidal.
7. Photophores
1. Integumental photophores absent.
2. Eyelid photophore present; 1 mm wide
image info

Figure. Side view of the head of M. glaukopis showing the eyelid photophore (arrow), holotype. Photograph by R. Young.

8. Pigmentation
1. Vivid reddish-brown color.
2. Sparse chromatophores on tentacles and oral surfaces of arms.
9. Measurements
Measurements according to Chun (1910) are: Mantle length - 37 mm; mantle width - 8 mm; eye diameter - 5.5 mm ML; tentacle length - 84 mm; club length - 58 mm.

Comments

Although we have examined the holotype, most of the above description, with the exception of the photographs, is from Chun (1910) since many features are no longer apparent on the holotype. This young mastigoteuthid is similar to M. atlantica and M. famelica in lacking integumental photophores but having a large photophore on each eyelid. It differs from both species in the structure of the club suckers (ie, small size; absence of large lateral pegs on outer ring). Since these latter features change with size, we can find no differences that separate M. glaukopis Chun, 1908 and it is probably synonymus with M. atlantica Joubin, 1933 or M. famelica Berry, 1909, but has priority over both. Until larger specimens of M. glaukopis are available from the Indian Ocean, we maintain all three species. We suspect, however, on the basis of the distinct protective membrane on the tentacular club in the illustrations of Chun (1910) (see above) that M. glaukopis and M. atlantica may be synonymous.

Distribution

Type locality: Indian Ocean off east African coast at 4°63'N, 48°37'E.

References

Chun, C. 1910. Die Cephalopoden. Oegopsida. Wissenschaftliche Ergebnisse der Deutschen Tiefsee Expedition auf dem Dampfer "Valdivia" 1898-1899, 18(1):1-401.