The Neoteuthidae contains weakly muscled species of small to moderate size (up to 27 cm). They are distinctive in having peculiar fins in which free posterior fin lobes are present and anterior lobes are absent. In addition, the fins attach laterally on the mantle muscle. The tentacular club is unusual in having the manus divided into two distinct regions: a proximal-manus carrying numerous small suckers in irregular series and a distal-manus mostly carring four regular series (may be slightly more suckers in initial portion) of larger suckers. The appearance of the club is similar to that of some species of brachioteuthids. Little is known about the biology of this group.

Brief diagnosis:

An oegopsid ...

• with more than 10 irregular series of suckers on proximal manus of tentacular club.
• with anterior attachments of fins to the sides of the mantle rather than on gladius.
• with free posterior lobes on fins.

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

1. Arms
   1. Arms with biserial suckers.
   2. Buccal connectives attach to the dorsal margins of arms IV.
      
      
2. Tentacles
   1. Manus of tentacular club divided into two regions, a distal manus with large suckers in mostly four series and a proximal manus with small suckers in more than 10 series. (The number of series may be slightly more at the interface between the proximal and distal manus and, in Narrowteuthis, somewhat less on the distal portion of the dactylus.)
      
   2. Club locking apparatus extends, at least, along the length of the proximal manus.
      
      

      Figure. Top - Oral views of tentacular clubs of Neoteuthis thielei, 83 mm ML, off California. drawing from Young, 1978. Bottom - Alluroteuthis antarctica, Antarctic waters. Drawing from Roper, et al., 1969.

3. Funnel
   1. Funnel with straight locking-apparatus.
      
      
4. Fins
   1. Anterior fin lobes absent; posterior fin lobes free.
   2. Fins mostly attach to dorsolateral sides of mantle.
      

      Figure. Left - Dorsal view of mantle of Neoteuthis sp., 83 mm ML, off California (from Young, 1972). Right - Ventral view of mantle of Alluroteuthis antarctica (from Roper et al., 1969).

5. Photophores
   1. Photophores absent.
      
      
6. Skin
   1. Outer surfaces of arms, head and mantle with thick white tissue (presumably silver in life) in most genera.

Comments

The genera are compared in the following table:

Genus	Club length	Proximal-manus length relative to remaining distal club length	tentacle locking apparatus	Manal sucker laterally compressed	Two greatly enlarged suckers on distal manus	Arm sucker dentition	Fin length
Alluroteuthis	33% ML	<1/3 X	Manus, stalk	No	No	Single large tooth	35-40% ML
Neoteuthis	60% ML	4.8 X	Manus	No	No	Truncated teeth	70% ML
Nototeuthis	37% ML	3/4 X	Manus, stalk	No	Yes	Truncated teeth	60% ML
Narrowteuthis	20% ML	1.1 X	Manus, stalk	Yes	No	Smooth	35% ML

No paralarva of any neoteuthid has been positively identified. However, a paralarva off Hawaii was tentatively identified to this genus by a process of elimination rather than the more reliable process of following a size series to identifiable juveniles. One of the keys to identification is the position of the digestive gland in an anterior postion adjacent to the cephalic cartilage. This feature is usually characteristic of families with buccal connectives that attach to the dorsal borders of arms IV. This paralarva had thick, iridescent tissue overlying the posterior part of the head but much of the skin was missing from other regions so the extent of iridescent tissue in an undamaged paralarva is unknown. Head and arm chromatophore patterns are incomplete due to damage. The dotted line indicates the size and position of the digestive gland.