Afrololigo mercatoris (Adam, 1941)

Type species. -- Lolliguncula mercatoris Adam, 1941 by original designation.

Introduction

A. mercatoris is a small species with females reaching 5 cm ML and males 3.5 cm ML. In general appearance it resembles species of Lolliguncula and Loliolus. Afrololigo mercatoris is known only from the west African coast where it has been collected at depths of less than 50 m on mud and sandy mud bottoms.

Brief diagnosis:

A loliginid ...

• with short mantle, rounded posteriorly; fins wider than long but without posterior lobes.
• without a ventral crest on the hectocotylus.
• with distribution restricted to waters off West Africa.

Characteristics

1. Arms
1. Arms I extremely short compared to other arms.
2. Arm sucker rings with square, plate-like teeth around entire margin.
3. Suckers on mid-sections of lateral arms of males greatly enlarged.


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Figure. Dorsolateral view of the brachial crown of Afrololigo mercatoris, male, 04°06'N, 05°58'E.

4. Hectocotylus (left arm IV):
1. Ventral crest absent.
2. Proximal half with 6-12 pairs of normal suckers.
3. Distal half with elongate papillae replacing suckers, papillae of dorsal series more strongly developed.
   
   
2. Tentacles
1. Tentacular clubs narrow, small; suckers in four series.
2. 4 or 5 pairs of medial suckers on manus much larger than lateral suckers.
3. Club sucker rings with 15-25 teeth.
   
   
3. Head
1. Head short.
2. Buccal supports without suckers.
   
   
4. Mantle
1. Mantle bluntly rounded posteriorly; without posterior tail-like elongation.
   
   
5. Fins
1. Fins rounded, short (length 40 - 45% ML), broad (55 - 65% ML) with convex posterior margins.
   
   
6. Photophores
1. Photophores absent.
   
   
7. Viscera
1. Eggs small.
2. Spermatophores with long cement body.

Comments

Many of the morphological characters of Afrololigo mercatoris are shared with species of Lolliguncula, the genus in which it was originally described. DNA sequence analysis by Anderson (2000) supports Brakoniecki's (1986) conclusion that Afrololigo is a distinct genus.

Distribution

Eastern central Atlantic: limited to the west coast of Africa from Rio de Oro (Mauritania) to Lüderitz Bay (Namibia).

Remarks

“Loligo” abulati Adam 1955 in the Red Sea appears to be closely related to A. mercatoris, but is too poorly known to include in the species accounts.

Other Names for Afrololigo mercatoris (Adam, 1941)

• Afrololigo Brakoniecki 1986
• Vernacular Names: Guinean thumbstall squid

References

Anderson, F.E. 2000. Phylogeny and historical biogeography of the loliginid squids (Mollusca: Cephalopoda) based on mitochondrial DNA sequence data. Molecular Phylogenetics and Evolution 15: 191-214.

Brakoniecki, T.F. 1986. A Generic Revision of the Family Loliginidae (Cephalopoda; Myopsida) Based Primarily on the Comparative Morphology of the Hectocotylus. Ph.D. Dissertation, University of Miami, Miami, FL, USA. 163 pages.

Vecchione, M., E. Shea, S. Bussarawit, F. Anderson, D. Alexeyev, C.-C. Lu, T. Okutani, M. Roeleveld, C. Chotiyaputta, C. Roper, E. Jorgensen and N. Sukramongkol. 2005. Systematics of Indo-West Pacific loliginids. Phuket Mar. Biol. Cent. Res. Bull. 66: 23-26.