Callichirus major

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Callichirus major
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Family: Callianassidae
Genus: Callichirus
Species:
C. major
Binomial name
Callichirus major
Say, 1818
Species

C. macrotelsonis, C. major s.s., C. aff. major sp. 1, C. aff. major sp. 2

Synonyms
  • Callianassa major Say, 1818

Callichirus major sensu lato is a monophyletic species complex of ghost shrimp in the infraorder Axiidea, found in flat sandy beaches across the Pan-American coastline.

Originally described as a single species, genetic studies eventually classified it as at least four almost morphologically indistinguishable species, one of which was given the binomial denomination Callichirus macrotelsonis (Peiró, 2012). The complex is distinguished by

hermaphroditism
in C. macrotelsonis.

The widespread extraction of individuals for living fishing bait has endangered both its conservation and that of their respective ecosystems.

Taxonomy

Callichirus major was first described as Callianassa major by

crustaceans until this infraorder was proven to be paraphyletic in 2009, after which the family Callianassidae, in which C. major is included, was definitely placed in the infraorder Axiidae (de Saint Laurent, 1979).[3] A supposed Brazilian species described as Anomalocaris macrotelsonis (Ortmann, 1893) was eventually discovered in 1974 to be the fourth larval stage of C. major.[4]

In 1995, the results of genetic testing published by Staton and Felder concluded that Caribbean Colombian populations described as C. major could not belong to the same species as those found in the United States Atlantic Ocean. Among those in the United States, although there were minor morphological differences between the populations of the East Coast (from North Carolina to Georgia) and those of the Gulf of Mexico (from Louisiana to Texas), the overall internal diversity of each population made them genetically indistinguishable.[5] Samples of Pacific Mexican ghost shrimps also later suggested a species not identical, but close to C. major s.s.[6]

Further testing by Peiró confirmed that populations of the East Coast and the Gulf of Mexico belonged to the same species, which was in turn different from the Colombian ones, but C. major was definitely described not as only two, but four distinct species with a

hermaphroditism in C. major s.s. might indicate that this feature could be exclusive of the Brazilian species, which she denominated C. brasiliensis sp. nov.[9]

Based on descriptions by Sakai and Türkay in 2012, Felder and Dworschak suggested that the formers' denomination C. santarosaensis might be ascribed to populations formerly designated as C. major in the northern Gulf of Mexico, although pending further genetic analysis and casting doubt on the validity of Sakai's and Türkay's description of a damaged juvenile specimen, prejudicing the validity of the taxon.[10][11]

Description

The great morphological similarities between all species of the C. major complex has proven to be a difficulty for the distinction of its closely related species.[12]

The C. major has a

basal segment of the antennules' peduncles. The antennules have a third segments 1.5 to 2.5 times as longer as the first and second together.[13]

The maxilla has distinctly separated coxae and bases. The first pair of pereopods is very unequal in size, especially in adult males, presenting a uniquely bold instance sexual dimorphism in the genus. The second pair is well chelated, but the fourth and fifth have rather imperfect chelae. The first and second segments of the abdomen are membranous and soft, the latter being longer than the first, and almost twice as long as the third, fourth and sixth segments. The third, fourth and sixth segments have approximately the same length, although the fifth is slightly longer than its adjacent segments.[14]

Distinctly for its genus, C. major is

sister species such as C. seillacheri, however, implies that the genus Callichirus may have a unique case of crustacean basal, but not universal, hermaphroditism.[15]

Habitat

C. major s.l. occurs in open, dissipative and flat sandy beaches, mostly in deep galleries in the

subtidal depths of 2–3 m.[1] It has a very large geographic distribution across Pan-American coastlines. In the Atlantic coastline, the distribution occurs from North Carolina to Santa Catarina, although with a large hiatus from Southern Texas to Pará, being therein only sporadically found in Colombia and Venezuela.[1][16] In the Pacific coastline, the complex has been identified in both Baja California and Costa Rica.[8][16]

C. major s.l. is widely employed as living

critically endangered, although it has not been officially reviewed by the IUCN.[19]

See also

References

Wikimedia Commons has media related to Callichirus major.

Citations

  1. ^ a b c Peiró 2012, p. 43.
  2. ^ Peiró 2012, p. 16.
  3. ^ Peiró 2012, p. 14.
  4. ^ Peiró 2012, pp. 44–5.
  5. ^ Staton & Felder 1995, pp. 528–31.
  6. ^ Peiró 2012, p. 46.
  7. ^ Peiró 2012, pp. 11, 47.
  8. ^ a b Peiró 2012, p. 52.
  9. ^ Rio 2018, p. 13.
  10. ^ Felder & Dworschak 2015, pp. 270–1.
  11. ^ Rio 2018, p. 31.
  12. ^ Peiró 2012, p. 89.
  13. ^ Peiró 2012, pp. 65–6.
  14. ^ Peiró 2012, pp. 66–70.
  15. ^ Rio 2018, pp. 56–9.
  16. ^ a b Peiró 2012, pp. 54–5.
  17. ^ Peiró 2012, p. 17.
  18. ^ Souza & Borzone 2003, p. 625.
  19. ^ Peiró 2012, pp. 150–1.

Sources

  • Felder, Darryl L.; Dworschak, Peter C. (2015). "Comments on two questionably new axiidean taxa from the Gulf of Mexico (Crustacea: decapoda)". Zootaxa. 4057 (2): 265–272.
    PMID 26701479
    .
  • Peiró, Douglas Fernando (2012). Status taxonômico de Callichirus major (Say, 1818) sensu lato (Crustacea, Decapoda, Axiidea, Callianassidae) da costa brasileira: taxonomia, sistemática molecular, biologia populacional e reprodutiva (PDF) (PhD) (in Portuguese and English). Retrieved 19 May 2020.
  • Rio, Juliana Priscila Piva (2018). Taxonomia, morfologia reprodutiva e crescimento relativo no camarão-fantasma Callichirus major (Say, 1818) (Decapoda: Callianassidae), no sudeste do Brasil (PDF) (PhD) (in Portuguese and English). Retrieved 19 May 2020.
  • Staton, J. L.; Felder, D. L. (1995). "Genetic variation in populations of the ghost shrimp genus Callichirus (Crustacea: Decapoda: Thalassinoidea) in the western Atlantic and Gulf of Mexico". Bulletin of Marine Science. 56 (2): 532–536.
  • Souza, José; Borzone, Carlos (2003). "A extração de corrupto, Callichirus major (Say) (Crustacea, Thalassinidea), para uso como isca em praias do litoral do Paraná: as populações exploradas". Revista Brasileira de Zoologia (in Portuguese). 40 (4). Curitiba: 625–630.
    doi:10.1590/S0101-81752003000400011
    . Retrieved 18 May 2020.
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