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Ghost shrimp Calliax de Saint Laurent, 1973 (Decapoda: Axiidea: Callianassidae) in the fossil record: systematics, palaeoecology and palaeobiogeography.

Hyžný M, Gašparič R - Zootaxa (2014)

Bottom Line: Thorough comparison of extant members of the genus resulted in evaluation of characters present on chelipeds being taxonomically important on the genus level, specifically: 1) rectangular major P1 propodus with two ridges on the base of the fixed finger extending onto manus; 2) major P1 fingers relatively short; and 3) minor P1 chela with dactylus longer than fixed finger and possessing a wide gap between fingers.The known geographic distribution of C. michelottii is expanded by the first confirmed occurrence of the species in Slovakia.Based on the scarce fossil record known to date, Calliax has a Tethyan origin; it supposedly migrated westward to establish present day communities in the Caribbean sometime before the Middle Miocene.

View Article: PubMed Central - PubMed

Affiliation: Geological-Paleontological Department, Natural History Museum, Vienna, Burgring 7, A-1010 Vienna, Austria.; Email: matus.hyzny@nhm-wien.ac.at.

ABSTRACT
Ghost shrimps of the family Callianassidae are very common in the fossil record, but mostly as isolated cheliped elements only. The assignment to biologically defined genera, diagnosed on the basis of soft part morphology, is thus rather difficult. In this respect, proxy characters present on chelipeds that are the most durable ghost shrimp remains are needed to ascribe fossil material to extant genera. The genus Calliax de Saint Laurent, 1973 has been particularly obscure in this respect. Thorough comparison of extant members of the genus resulted in evaluation of characters present on chelipeds being taxonomically important on the genus level, specifically: 1) rectangular major P1 propodus with two ridges on the base of the fixed finger extending onto manus; 2) major P1 fingers relatively short; and 3) minor P1 chela with dactylus longer than fixed finger and possessing a wide gap between fingers. On this basis, Callianassa michelottii A. Milne Edwards, 1860, from the Oligocene and Miocene of Europe is herein reassigned to Calliax. Further re-examination of the ghost shrimp fossil record revealed that C. szobensis Müller, 1984, from the Middle Miocene of Hungary represents the same animal as C. michelottii and they are synomymised herein. The known geographic distribution of C. michelottii is expanded by the first confirmed occurrence of the species in Slovakia. All occurrences of C. michelottii known to date are reviewed and documented. The presence of Calliax michelottii comb. nov. may be considered an indicator of deeper marine settings. Based on the scarce fossil record known to date, Calliax has a Tethyan origin; it supposedly migrated westward to establish present day communities in the Caribbean sometime before the Middle Miocene.

No MeSH data available.


Related in: MedlinePlus

Comparison of figured major chela of Calliax: A, Calliax cf. C. lobata (NHMW 25511); B, Calliax lobata (redrawn after de Saint Laurent & Božić 1976: fig. 23a); C, Calliax lobata (redrawn after Ngoc-Ho 2003: fig. 17D); D, Calliax doerjesti (redrawn after Sakai 1999: fig. 29b). All figures are to scale.
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Figure 4: Comparison of figured major chela of Calliax: A, Calliax cf. C. lobata (NHMW 25511); B, Calliax lobata (redrawn after de Saint Laurent & Božić 1976: fig. 23a); C, Calliax lobata (redrawn after Ngoc-Ho 2003: fig. 17D); D, Calliax doerjesti (redrawn after Sakai 1999: fig. 29b). All figures are to scale.

Mentions: The number of spines on the lower margin of P1 merus may vary between respective members of Calliax and may help in distinguishing taxa at the species level, although possible variation has not been studied in detail yet. Regarding the number of meral spines, there are discrepancies in the literature. Sakai (1999: 114) in the description of C. doerjesti mentioned that the lower margin of the merus was “armed with three interspaced denticles”. One of the figures (Sakai 1999: fig. 29b) indeed shows three small spines, however, in the other one (Sakai 1999: fig. 28) depicting the same specimen (holotype) the merus is armed with seven spines (Fig. 3a). Ngoc-Ho (2003: fig. 17D; note that the published figure depicts the right major chela, whereas the caption refers to it as the left one) figured the holotype (male) of C. lobata with seven spines on the merus and de Saint Laurent & Božić (1976: fig. 23a) figured a female specimen of C. lobata also with seven spines. Calliax cf. C. lobata, examined and figured herein (Figs 2, 3E–F), possesses only four blunt spines, presumably mirroring its small size (Fig. 4).


Ghost shrimp Calliax de Saint Laurent, 1973 (Decapoda: Axiidea: Callianassidae) in the fossil record: systematics, palaeoecology and palaeobiogeography.

Hyžný M, Gašparič R - Zootaxa (2014)

Comparison of figured major chela of Calliax: A, Calliax cf. C. lobata (NHMW 25511); B, Calliax lobata (redrawn after de Saint Laurent & Božić 1976: fig. 23a); C, Calliax lobata (redrawn after Ngoc-Ho 2003: fig. 17D); D, Calliax doerjesti (redrawn after Sakai 1999: fig. 29b). All figures are to scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4402405&req=5

Figure 4: Comparison of figured major chela of Calliax: A, Calliax cf. C. lobata (NHMW 25511); B, Calliax lobata (redrawn after de Saint Laurent & Božić 1976: fig. 23a); C, Calliax lobata (redrawn after Ngoc-Ho 2003: fig. 17D); D, Calliax doerjesti (redrawn after Sakai 1999: fig. 29b). All figures are to scale.
Mentions: The number of spines on the lower margin of P1 merus may vary between respective members of Calliax and may help in distinguishing taxa at the species level, although possible variation has not been studied in detail yet. Regarding the number of meral spines, there are discrepancies in the literature. Sakai (1999: 114) in the description of C. doerjesti mentioned that the lower margin of the merus was “armed with three interspaced denticles”. One of the figures (Sakai 1999: fig. 29b) indeed shows three small spines, however, in the other one (Sakai 1999: fig. 28) depicting the same specimen (holotype) the merus is armed with seven spines (Fig. 3a). Ngoc-Ho (2003: fig. 17D; note that the published figure depicts the right major chela, whereas the caption refers to it as the left one) figured the holotype (male) of C. lobata with seven spines on the merus and de Saint Laurent & Božić (1976: fig. 23a) figured a female specimen of C. lobata also with seven spines. Calliax cf. C. lobata, examined and figured herein (Figs 2, 3E–F), possesses only four blunt spines, presumably mirroring its small size (Fig. 4).

Bottom Line: Thorough comparison of extant members of the genus resulted in evaluation of characters present on chelipeds being taxonomically important on the genus level, specifically: 1) rectangular major P1 propodus with two ridges on the base of the fixed finger extending onto manus; 2) major P1 fingers relatively short; and 3) minor P1 chela with dactylus longer than fixed finger and possessing a wide gap between fingers.The known geographic distribution of C. michelottii is expanded by the first confirmed occurrence of the species in Slovakia.Based on the scarce fossil record known to date, Calliax has a Tethyan origin; it supposedly migrated westward to establish present day communities in the Caribbean sometime before the Middle Miocene.

View Article: PubMed Central - PubMed

Affiliation: Geological-Paleontological Department, Natural History Museum, Vienna, Burgring 7, A-1010 Vienna, Austria.; Email: matus.hyzny@nhm-wien.ac.at.

ABSTRACT
Ghost shrimps of the family Callianassidae are very common in the fossil record, but mostly as isolated cheliped elements only. The assignment to biologically defined genera, diagnosed on the basis of soft part morphology, is thus rather difficult. In this respect, proxy characters present on chelipeds that are the most durable ghost shrimp remains are needed to ascribe fossil material to extant genera. The genus Calliax de Saint Laurent, 1973 has been particularly obscure in this respect. Thorough comparison of extant members of the genus resulted in evaluation of characters present on chelipeds being taxonomically important on the genus level, specifically: 1) rectangular major P1 propodus with two ridges on the base of the fixed finger extending onto manus; 2) major P1 fingers relatively short; and 3) minor P1 chela with dactylus longer than fixed finger and possessing a wide gap between fingers. On this basis, Callianassa michelottii A. Milne Edwards, 1860, from the Oligocene and Miocene of Europe is herein reassigned to Calliax. Further re-examination of the ghost shrimp fossil record revealed that C. szobensis Müller, 1984, from the Middle Miocene of Hungary represents the same animal as C. michelottii and they are synomymised herein. The known geographic distribution of C. michelottii is expanded by the first confirmed occurrence of the species in Slovakia. All occurrences of C. michelottii known to date are reviewed and documented. The presence of Calliax michelottii comb. nov. may be considered an indicator of deeper marine settings. Based on the scarce fossil record known to date, Calliax has a Tethyan origin; it supposedly migrated westward to establish present day communities in the Caribbean sometime before the Middle Miocene.

No MeSH data available.


Related in: MedlinePlus