Thymopsis nilenta
| Thymopsis nilenta | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Thymopsis | ||||||||||||
| Holthuis , 1974 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Thymopsis nilenta | ||||||||||||
| Holthuis, 1974 |
Thymopsis nilenta is a species of decapod from the monotypic genus Thymopsis . So far, 10 specimens of thislobster species nativeto the deep sea of the South Atlantic have been found.
description
The rostrum is rather slim, its back surface is flattened and has five to eight lateral points. Starting from the rostrum, two spiked ridges run backwards. The sometimes clearly pronounced ridges or depressions on the carapace are provided with many small points or finely granulated. The individual segments ( somites ) of the pleon have a transverse depression. The telson is rectangular, its surface is granulated and has two rather indistinct ridges that end in obliquely backward (posterolateral) spines.
The eyes are greatly reduced and not pigmented. The antennas have stylocerite, elevations on the antenna base (antennular peduncle). The epistome is smooth, the second and third maxillipedas lack the exopodites .
The large scissors on the first pair of striding legs are the same, slightly compressed on the sides and have many small points on their surface. The length of the scissor finger is as long as the scissor hand. The cut edges are provided with 20 to 25 small teeth. The tips of the scissor fingers are rounded inward and cross each other when the scissors are closed. There are very small scissors on the second and third pair of striding legs, the fourth and fifth are scissorless. In contrast to the first pair of striding legs, the remaining pairs are smooth, have no tips or thorns, but isolated tufts of hair.
In males, the first pair of swimming legs is short and stocky. In contrast to those of the females, the separation of the two segments can no longer be seen. On the male's second pair of swimming legs, the "Appendix masculina", a kind of bracket-like appendix, is very short. In both males and females, the endo- and exopodites of the swimming leg pairs two to five are relatively elongated. The uropods are relatively large and longer than the telson. The exopodite of the uropods, which is slightly hairy on the edge, has a clear diaeresis, a transverse depression.
Thymopsis nilenta reaches a body length of 15 cm, the carapace length excluding the rostrum being 5 to 6 cm.
distribution and habitat
Thymopsis nilenta is native to the South Atlantic near the Falkland Islands and South Georgia . The populated sea depths are between 2000 and 3000 m. Nothing is known about the ecology and the habitat. Among other things, due to the deep sea depths, no endangerment of the species is suspected, which is why it is classified as "Least Concern".
Systematics and taxonomy
In addition to this species or genus , Lipke Holthuis described the genus Thymops Holthuis, 1974 and placed it with Thymopsis in its own subfamily , the Thymopinae Holthuis, 1974 . Results of a phylogenetic investigation do not support the division of the lobster-like family into subfamilies, which is why these are no longer in use.
The suffix '-opsis' means 'external appearance of', the generic name therefore refers to the morphological similarities with thymops . Tymopsis differs from the latter , as well as from every other genus of lobster-like, in the absence of exopodites on the second and third maxillipedas . The holotype of the species Thymopsis nilenta was caught in 1966 during an expedition of the research vessel USNS Eltanin south of South Georgia ( 60 ° 06'S, 36 ° 02'W ). The specific epithet "nilenta" is not explained.
literature
Individual evidence
- ↑ Thymopsis nilenta Holthuis, 1974. (No longer available online.) In: Antarctic Invertebrates. Smithsonian National Museum of Natural History, archived from the original on November 16, 2016 ; accessed on June 30, 2012 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b c d e f g Lipke B. Holthuis: The Lobsters of the Superfamily Nephropidea of the Atlantic Ocean (Crustacea: Decapoda) . In: Bulletin of Marine Science . tape 24 , no. 4 , 1974, p. 723–884 ( nhm.org [PDF; 16.0 MB ; accessed on June 30, 2012]).
- ^ Lipke B. Holthuis: Marine Lobsters of the World . An Annotated and Illustrated Catalog of Species of Interest to Fisheries Known to Date. Ed .: Food and Agriculture Organization (= FAO Fisheries Synopsis . Volume 125 ). Rome 1991, ISBN 978-92-5103027-1 .
- ↑ Thymopsis nilenta in the endangered Red List species the IUCN 2012. Posted by: Wahle, R., 2011. Accessed June 30, 2012th
- ↑ Dale Tshudy, Rafael Robles, Tin-Yam Chan, Ka Chai Ho, Ka Hou Chu, Shane T. Ahyong, Darryl L. Felder: Phylogeny of marine clawed lobster families Nephropidae Dana, 1852, and Thaumastochelidae Bate, 1888, based on mitochondrial genes . In: Joel W. Martin, Keith A. Crandall, Darryl L. Felder (Eds.): Decapod Crustacean Phylogenetics . CRC Press, 2009, ISBN 1-4200-9258-8 , pp. 357–368 ( nhm.org [PDF; 1,2 MB ; accessed on July 1, 2012]).
