Socorro woodlouse
| Socorro woodlouse | ||||||||||||
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Male from the Socorro Isopod Propagation Facility |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Thermosphaeroma thermophilum | ||||||||||||
| ( H. Richardson ), 1897 |
The Socorro isopod ( Thermosphaeroma thermophilum ) is a North American freshwater isopod that was only found at a warm spring in New Mexico and has since become extinct in the original wild population. However, there are several populations in artificial habitats and in captivity. The main threat to the species is now vandalism on these same systems.
features
Socorro woodlice are flattened woodlice with a body about twice as long as it is wide. The head is relatively short and rounded and has eyes and two pairs of antennae of about the same length. The animals are gray-brown with black dots and stripes that together form a broad dark band in the middle of the thoracic segments . All edges of the body are colored bright orange. While the females reach an average of 5.1 and a maximum of 21 millimeters in length, the males are significantly larger with an average of 7.8 and a maximum of 60 millimeters in length. The peraeon with the seven pairs of legs is not very hairy and becomes slightly wider towards the rear. The abdomen is broad and evenly rounded and has two oar-like uropods , making the species distinguishable from all other woodlice in New Mexico. The Socorro isopod can be distinguished from the other species of the genus by its rounded abdomen without a central ridge and the short exopodites of the uropods.
Way of life
Socorro woodlice occur in warm spring water with temperatures between 27 and 34 ° C. The animals are nocturnal and spend the day buried in the substrate . They feed mainly on cyanobacteria growing in mats , but also take in detritus and prey on Tubifex worms and insect larvae. Injured conspecifics are also eaten, with injured animals being quickly attacked by groups of 10 to 30 animals and being completely eaten within an hour. The lifespan is estimated to be eight months to a year.
Reproduction
Reproduction occurs throughout the year, peaking in April and then decreasing to the minimum in late summer. With good nutrition, the females are able to reproduce every two months. They are guarded by the males who form a pair with them for several days and swim together through the habitat. In the laboratory, the females lay 3 to 57 eggs, an average of 16, which are carried in the marsupium until the young hatch after about 30 days and swim away.
Occurrence and endangerment
The only known occurrence of the species was limited to a warm runoff from the Sedillo spring about three kilometers west of the city of Socorro in Socorro County (New Mexico). It may also have inhabited the nearby Cook and Socorro springs earlier, but where it was never proven. In the late Pleistocene and early Holocene, these three sources fed a now dry marshland , which could represent the original range of the species.
The original habitat of the Socorro-Assel was destroyed in the 1970s by enclosing the spring for the construction of a thermal bath . However, the species managed to survive in two tanks and around 50 meters of piping, where, possibly due to the lack of predators, they reached high population densities of up to 210 animals per 100 square centimeters. In the late 1970s, the population remained stable at around 2500 animals.
In 1988 the occurrence collapsed when the inflow of water was almost cut off by root growth, but recovered after the inflow was reopened a month later and animals that had previously been kept at the University of New Mexico settled . In 1990, in response to this near-extinction, the Socorro Isopod Propagation Facility was established, which consists of two independent systems with four tanks. In 1998 a third captive population was established in the Albuquerque Biological Park and subsequently another in the Department of Game and Fish in Santa Fe .
The species is still threatened by changes in the water flow, underground attempts at explosions by the Ministry of Defense and, above all, by vandalism at the facilities. Between 1995 and 2003, for example, valves and pipes were dismantled, the flow of water blocked, pools damaged, a car disposed of directly next to the spring and plants removed from the breeding pool. In addition, the population in the Socorro Isopod Propagation Facility now differs morphologically and genetically from the wild population, which could be due to different selection conditions. The Socorro woodlouse is listed as Extinct in the Wild on the IUCN Red List and is protected as an Endangered Species in the United States.
literature
- Susan M. Wells, Robert M. Pyle, N. Mark Collins (Eds.): The IUCN Invertebrate Red Data Book . IUCN, Gland 1983, ISBN 2-88032-602-8 , pp. 283-285 .
Individual evidence
- ↑ a b c d Susan M. Wells, Robert M. Pyle, N. Mark Collins (Eds.): The IUCN Invertebrate Red Data Book . IUCN, Gland 1983, ISBN 2-88032-602-8 , pp. 283-285 (English).
- ↑ a b Socorro Isopod (PDF; 57 kB) at the New Mexico Department of Game & Fish
- ↑ Thomas E. Bowman: Thermosphaeroma milleri and T. smithi, new Sphearomatid Isopod Crustaceans drom Hot Springs in Chihuahua, Mexico, with a Review of the Genus . In: Journal of Crustacean Biology . tape 1 , no. 1 , 1981, p. 105–122 (English, full text [PDF; 873 kB ]).
- ↑ Stephen M. Shuster: Life history characteristics of Thermosphaeroma thermophilum, the Socorro isopod (Crustacea: Peracarida) . In: The Biological Bulletin . tape 161 , 1981, pp. 291-302 , doi : 10.2307 / 1540805 (English).
- ↑ a b Socorro Isopod at biologicaldiversity.org
- ↑ a b Thermosphaeroma thermophilum in the endangered Red List species the IUCN 2011. Posted by: Inland Water Crustacean Specialist Group., 1996