Palaemon concinnus
| Palaemon concinnus | ||||||||||||
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| Palaemon concinnus | ||||||||||||
| ( Dana , 1852) |
Palaemon concinnus is a species of shrimp from the genus of rock shrimp ( Palaemon ) within the family of rock and partner shrimp (Palaemonidae).
features
The females grow to around 70 mm, while the males only grow to 60 mm. The distal half of the slightly tapered rostrum is slightly curved upwards. The rostral formula is 1 + 5–8 / 3–7 (subapical teeth + back teeth / abdominal teeth). On the basal segment of the anterior antennae, there is a distolateral spine (away from the body and to the side) which clearly protrudes over the adjacent distal, convex edge of the segment. The free part of the shorter branch (ramus) of the dorsal flagellum of the antennula is 3.5 to 6 times as long as the fused part. The mandibles have three segmented palpi . The first stride leg with carpus is 2.5 to 3 times as long as the chela , the second stride leg with carpus 1.5 to 2 times as long as the chela. On the fifth abdominal pleuron there is a distoventral spine, on the first pleopod of the male there is an appendix on the edge of the endopod.
The rostrum is largely transparent; there are only a few chromatophores distally . Scattered chromatophores form pale red-brown lines on the carapace . On the abdominal area, denser chromatophores form a strong horizontal band across the pleura . Between the fourth and fifth and the fifth and sixth abdominal segment there is a pale brown spot on the side. At the posterior end of the sixth abdominal segment there is a dark spot under the cuticle . The joint between the carpus and chela of the second stride leg is orange, that between carpus and merus is slightly orange. The joint between Propodus and Carpus as well as Carpus and Merus on the third to fifth stride bones is pigmented red-orange. The eggs are creamy white.
Palaemon concinnus is the only species of the genus with a rudimentary appendix to the endopodite of the first pleopod . Palaemon concinnus shares this characteristic with the species of the four genera Brachycarpus , Leander , Leandrites and Urocaridella of the subfamily of rock shrimp . However, it is not sufficient to justify a classification of Palaemon concinnus in one of the other genera.
distribution
Palaemon concinnus is widespread in the Indo-Pacific region. It occurs from the Suez Canal to South Africa and east to Hong Kong , the Philippines , Indonesia , the Marshall Islands , French Polynesia and Fiji .
habitat
In the literature there are references to the occurrence in fresh, brackish and salt water. However, it is unclear whether the species actually occurs in its range in all three water types. As a rule, it appears to inhabit fresh water or slightly brackish waters; occurrences in marine habitats require confirmation.
Individual evidence
- ↑ Features at www.wirbellose.de (accessed on September 20, 2016)
- ↑ a b c d Christopher Ashelby, Wei-Cheng Lin, Sammy De Grave, Tin Yam Chan: Notes on the shrimp genus Palaemon Weber, 1795 (Crustacea, Decapoda, Palaemonidae) and related genera from Taiwan. , 2018, in: Zootaxa. 4446. ( Online )
- ↑ Sammy De Grave, Christopher Ashelby: A re-appraisal of the systematic status of selected genera in Palaemoninae (Crustacea: Decapoda: Palaemonidae). 2013 in Zootaxa. 3734, pp. 331-344. ( Online )