Asperoteuthis
Page authors: Richard E. Young, Clyde F. E. Roper, Michael Vecchione
Little is known about the biology of any species of Asperoteuthis. The most peculiar feature of this genus is the structure of the tentacular clubs. The distal part of the club has typical suckers and suggests that this part of the club functions in the usual capture of prey. The proximal part of the club lacks suckers and has broader protective membranes whose trabeculae are mostly fused. The function of the latter is less clear but relates to another problem: How can the long and extremely slender tentacles, which in A. acanthoderma can be 7-12 times the mantle length (Tsuchiya and Okutani, 1993), be deployed? Perhaps the wide protective membranes of the proximal region of the club, which are composed virtually entirely of muscular trabeculae, function as muscular fins that swim the club into position. THIS NEEDS TO BE REWRITTEN !
- Arms long, generally subequal in length in large specimens; subadults with Arms IV slightly longer.
- Tentacles with club divided into two portions by symmetrical protective membranes, and suckers only on distal portion of club.
© Kat Bolstad
- Head with olfactory organ located well posterior to each eye.
- Funnel valve present; funnel component of the funnel-mantle locking-apparatus variable: With inverted Y-shaped groove that poorly defines an elongate tragus and slender antitragus (A. acanthoderma) or a slender antitragus and a strong antitragus (A. lui) or a curved groove without an antitragus (A. mangoldi).
Ventral view of the funnel locking-apparatus. Left - A. acanthoderma, drawing by J. R. Schroeder. Middle - A. lui, drawing from Braid (2016). Right - A. mangoldae, drawing from Young, et al. (2007).
- Skin covered with small tubercules in A. acanthoderma and A. lui but not in A. mangoldae
Skin tubercles on female A. acanthoderma (ML ~670mm) from North Atlantic off Florida. Specimen was described by Judkins et al. (2009). 
© Chuck Stevenson
- Tail with “secondary fin” retained in adults
- Photophores:
- No photophores on viscera or Arms IV.
- Large photophore patch on ventral surface of each eyeball.
- Luminescent pads on tentacle stalks (also in Chiroteuthis).
- Aboral surface of club with large, distal photophore (see arrows - terminal position in A. acanthoderma and A. mangoldi, not considering the long, terminal papilla in the latter, well sub-terminal position in A. lui) and a lateral series of small photophores on each side of the aboral club in A. acanthoderma and A. mangoldi (not shown on drawing of latter) and these plus an additional series of midline photophores in A. lui.
These squid often lose the tentacles during capture, and can easily be confused with Grimalditeuthis (especially A. mangoldae which is of the same size and muscular consistency). However, the lack of a fused funnel-mantle locking apparatus in Asperoteuthis easily distinguishes them.
| A. acanthoderma | A. mangoldae | A. lui | |
| Number of tentacle club suckers | ~50 | ~50 | 120-180 |
| Skin tubercles | Yes | Yes | No |
| Mantle with circular depressions | No | No | Yes |
| Arm sucker dentition | 3-4 rounded teeth | 6-10 truncated teeth | 7-10 pointed teeth |
| Club sucker dentition | 9 broad, blunt teeth | ~ 25 truncated teeth | ~5-7 conical, pointed teeth |
| Arm II sucker size | Mid-arm suckers enlarged | No enlarged suckers | argest suckers mid-arm but not enlarged |
| Funnel locking-apparatus | Elongate tragus, reduced antitragus | Curved, slender oval | Elongate tragus, normal antitragus |
| Fin width | 35-40% of ML | 45-65% of ML | 52-60-68% % of ML |
| Distal aboral club photophore | Large, terminal | Small, terminal, except for long papilla | Small, subterminal |
| Series of aboral, club photophores | Lateral margins | Lateral margins | Lateral margins, midline |
Lu (1977) described Chiroteuthis acanthoderma. Nesis (1980) incorrectly synonymized this species with the incompletely described Chiroteuthis famelica Berry, 1909 (now = Mastigoteuthis famelica, see Young, 1991) and erected for it the new genus Asperoteuthis. The type species of the genus is C. acanthoderma Lu, 1977.
Paralarvae are known for one species of Asperoteuthis (see Asperoteuthis mangoldae).
- Judkins, H., D. A. Ingrao and C. F. E. Roper. 2009. First records of Asperoteuthis acanthoderma (Lu, 1977) (Cephalopoda: Oegopsida: Chiroteuthidae), from the North Atlantic Ocean, Straits of Florida, Proc. Biol. Soc. Wash., 122: 162-170.
- Lu, C. C. 1977. A new species of squid Chiroteuthis acanthoderma, from the Southwest Pacific (Cephalopoda, Chiroteuthidae). Steenstrupia, 4: 179-188.
- Nesis, K. N. 1980. Taxonomic position of Chiroteuthis famelica Berry. Bull. Moscow Obshch. Ispyt. Prirody, sect. Biology, 85: 59-66. [In Russian].
- Tsuchiya, K. and T. Okutani. 1993. Rare and interesting squids in Japan -X. Recent occurences of big squids from Okinawa. Venus, 52: 299-311.
- Young, R. E. 1978. Vertical distribution and photosensitive vesicles of pelagic cephalopods from Hawaiian waters. Fishery Bulletin, 76: 583-615.
- Young, R. E. 1991. Chiroteuthid and related paralarvae from Hawaiian waters. Bull. Mar. Sci., 49: 162-185.
- Young, R. E., M. Vecchione and C. F. E. Roper. 2007. A new genus and three new species of decapodiform cephalopods (Mollusca: Cephalopoda). Rev. Fish. Biol. Fisheries, 17: 353-365.