Africonus Explained

Africonus is a taxon of sea snails, marine gastropod mollusks in the family Conidae. Although originally described as a distinct subgenus, it is currently considered as an alternative representation of the cone snail genus, Conus.

Distinguishing characteristics

The Tucker & Tenorio 2009 taxonomy distinguishes Africonus from Conus in the following ways:[1]

Shell characters (living and fossil species)

The basic shell shape is conical to elongated conical, has a deep anal notch on the shoulder, a smooth periostracum and a small operculum. The shoulder of the shell is usually nodulose and the protoconch is usually multispiral. Markings often include the presence of tents except for black or white color variants, with the absence of spiral lines of minute tents and textile bars.

Radular tooth (not known for fossil species)

The radula has an elongated anterior section with serrations and a large exposed terminating cusp, a non-obvious waist, blade is either small or absent and has a short barb, and lacks a basal spur.

Geographical distribution

These species are found in the Indo-Pacific region.

Feeding habits

These species eat other gastropods including cones.

Shell characters (living and fossil species)

The protoconch is paucispiral, the whorl tops may be concave when viewed in cross section, with cords on the whorl tops that may be lost in middle spire whorls or persist thereafter. The shell has a shallow to moderately deep anal notch. The periostracum is smooth and thin, and the operculum is small.

Radular tooth (not known for fossil species)

The anterior section of the radula is usually shorter than the posterior section but in some species they are subequal in length, the lumen of the radular tooth is wide, a basal spur is present, the barb is short, and the blade is long and extends along most of the anterior section of the radular tooth. Serrations are usually in multiple rows with one or two rows of large serrations and rows of smaller serrations on either side, although serrations can be in a single row in juveniles or small specimens.

Geographical distribution

These species are endemic to the Cape Verde Islands in the West African Region.

Feeding habits

These species are vermivorous (meaning that they prey on marine worms).

Species

Prior to 2009, all species within the family Conidae were placed in one genus, Conus. In 2009 however, J.K. Tucker and M.J. Tenorio proposed a classification system for the over 600 recognized species that were in the family. Their classification proposed 3 distinct families and 82 genera for the living species of cone snails. This classification was based upon shell morphology, radular differences, anatomy, physiology, cladistics, with comparisons to molecular (DNA) studies. Published accounts of genera within the Conidae that include the genus Africonus include J.K. Tucker & M.J. Tenorio (2009), and Bouchet et al. (2011).[2]

Testing in order to try to understand the molecular phylogeny of the Conidae was initially begun by Christopher Meyer and Alan Kohn,[3] and is continuing, particularly with the advent of nuclear DNA testing in addition to mDNA testing.

Many authorities continue to use the traditional classification, where all species are placed in Conus within the single family Conidae including the current (October 2022) version of the World Register of Marine Species. The binomial names of species in the 82 cone snail genera listed in Tucker & Tenorio 2009 are currently recognized by the World Register of Marine Species as "alternative representations".[4] Debate within the scientific community regarding this issue continues, and additional molecular phylogeny studies are being carried out in an attempt to clarify the issue.[5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

In 2015, in the Journal of Molluscan Studies, Puillandre, Duda, Meyer, Olivera & Bouchet presented a new classification for the old genus Conus. Using 329 species, the authors carried out molecular phylogenetic analyses. The results suggested that the authors should place all cone snails in a single family, Conidae, containing four genera: Conus, Conasprella, Profundiconus and Californiconus. The authors group 85% of all known cone snail species under Conus, They recognize 57 subgenera within Conus, and 11 subgenera within the genus Conasprella.In this description of the family Conidae, Africonus is classified as a subgenus of Conus: Conus (Lautoconus) Monterosato, 1923 (type species: Conus mediterraneus Hwass in Bruguière, 1792) represented as Conus Thiele, 1929 [15]

All the species formerly classified in the genus Africonus are now considered as "alternate representations" of species in the genus Conus:

Species brought into synonymyThe following species were synonymized:

Further reading

External links

Notes and References

  1. Tucker J.K. & Tenorio M.J. (2009), Systematic Classification of Recent and Fossil Conoidean Gastropods, ConchBooks, Hankenheim, Germany, 295 pp.
  2. Bouchet P., Kantor Yu.I., Sysoev A. & Puillandre N. (2011). "A new operational classification of the Conoidea". Journal of Molluscan Studies 77: 273-308.
  3. Interview of Professor Alan Kohn, Professor Emeritus, Zoology Web site: 2009 Kohn . 2011-12-04 . dead . https://web.archive.org/web/20120227030848/http://www.seashell-collector.com/articles/interviews/2009-kohn.html . 2012-02-27 .
  4. http://www.marinespecies.org/aphia.php?p=taxdetails&id=14107 Classification: Traditionally, all cone shells have been included in the Linnaean genus Conus. Tucker & Tenorio (2009) have recently proposed an alternative shell- and radula-based classification that recognizes 4 families and 80 genera of cones. In WoRMS, we currently still recognize a single family Conidae (following Puillandre et al. 2011), but Tucker & Tenorio's 80 genera classification is presented as "alternative representation". [P. Bouchet, 14 Aug. 2011]
  5. C.M.L. Afonso & M.J. Tenorio (August 2011), A new, distinct endemic Africonus species (Gastropoda, Conidae) from Sao Vicente Island, Cape Verde Archipelago, West Africa, Gloria Maris 50(5): 124-135
  6. P. Bouchet, Yu I. Kantor, A. Sysoev, and N. Puillandre (March 2011), A New Operational Classification of the Conoidea, Journal of Molluscan Studies 77:273-308, at p. 275.
  7. N. Puillandre, E. Strong, P. Bouchet, M. Boisselier, V. Couloux, & S. Samadi (2009), Identifying gastropod spawn from DNA barcodes: possible but not yet practicable, Molecular Ecology Resources 9:1311-1321.
  8. P.K. Bandyopadhyay, B.J. Stevenson, J.P. Ownby, M.T. Cady, M. Watkins, & B. Olivera (2008), The mitochondrial genome of Conus textile, coxI-conII intergenic sequences and conoidean evolution. Molecular Phylogenetics and Evolution 46: 215-223.
  9. S.T. Williams & T.F. Duda, Jr. (2008), Did tectonic activity stimulate Oligo-Miocene speciation in the Indo-West Pacific? Evolution 62:1618-1634.
  10. R.L. Cunha, R. Castilho, L. Ruber, & R. Zardoya (2005), Patterns of cladogenesis in the venomous marine gastropod genus Conus from the Cape Verde Islands Systematic Biology 54(4):634-650.
  11. T.F. Duda, Jr. & A.J. Kohn (2005), Species-level phylogeography and evolutionary history of the hyperdiverse marine gastropod genus Conus, Molecular Phylogenetics and Evolution 34:257-272.
  12. T.F. Duda, Jr. & E. Rolan (2005), Explosive radiation of Cape Verde Conus, a marine species flock, Molecular Ecology 14:267-272.
  13. B. Vallejo, Jr. (2005), Inferring the mode of speciation in the Indo-West Pacific Conus (Gastropoda: Conidae), Journal of Biogeography 32:1429-1439.
  14. Monteiro A., Tenorio M. J. & Poppe G. T., 2004. The Family Conidae: The West African and Mediterranean species of Conus
  15. https://dx.doi.org/10.1093/mollus/eyu055 Puillandre N., Duda T.F., Meyer C., Olivera B.M. & Bouchet P. (2015). One, four or 100 genera? A new classification of the cone snails. Journal of Molluscan Studies. 81: 1-23

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