Chiltonia

Chiltonia is a genus of amphipod crustaceans endemic to New Zealand. Four species are known, three of which live in fresh waters. They were first discovered by Charles Chilton in 1898 and the genus Chiltonia was erected the following year by T. R. R. Stebbing in Chilton's honour.

Chiltonia
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Amphipoda
Family:	Chiltoniidae
Genus:	Chiltonia Stebbing, 1899 [1]
Species
Chiltonia enderbyensis Hurley, 1954 Chiltonia mihiwaka (Chilton, 1898) Chiltonia minuta Bousfield, 1964 Chiltonia rivertonensis Hurley, 1954

Chiltonia mihiwaka

C. mihiwaka was the first of the species of Chiltonia to be described, when Charles Chilton named it in 1898 as a species in the genus Hyalella. Subsequent taxonomic splits have restricted the name to the populations in the Southland and Otago regions in New Zealand's South Island.[2] Chilton's original material was collected on Mihiwaka, a hill near Port Chalmers, Otago. Adults are approximately 5 mm (0.20 in) long, 1.25 mm (0.049 in) wide and 2 mm (0.079 in) deep.[3]

Chiltonia enderbyensis

C. enderbyensis was named by Hurley in 1954 for the populations of Chiltonia living on New Zealand's subantarctic islands, namely Enderby Island (one of the Auckland Islands) and Campbell Island.[2] Males are approximately 8 mm (0.31 in) long, 1.75 mm (0.069 in) wide and 1.5 mm (0.059 in) deep, while females are 6–7 mm (0.24–0.28 in) long, 1.5 mm (0.059 in) wide and 1.5 mm (0.059 in) deep.[3]

Chiltonia rivertonensis

C. rivertonensis was also named by Hurley in 1954, for a population living in small streams near Riverton, Southland.[2] In November 2018 the Department of Conservation classified C. rivertonensis as "Nationally Critical" under the New Zealand Threat Classification System.[4] The species was judged as meeting the criteria for Nationally Critical threat status as a result of it occupying only in one location, the total area of which is less than 1 hectare. It is considered as being "Data Poor" and "Range Restricted" under that system.[4]

Chiltonia minuta

C. minuta was the last of the four species to be described, and its affinities remain unclear. Whereas all the other species occur in fresh water, C. minuta was collected under kelp on a beach on Campbell Island.[2]

Australia

Two species from Australia, C. subtenuis and C. australis were described by Sayce in 1901 and 1902, respectively. Both are now considered to belong to the related genus Austrochiltonia.[5]

References

1. J. Lowry (2009). "Chiltonia Stebbing, 1899". World Register of Marine Species. Retrieved April 14, 2010.
2. Graham D. Fenwick (2001). "The freshwater Amphipoda (Crustacea) of New Zealand: a review". Journal of the Royal Society of New Zealand. 31 (2): 341–363. doi:10.1080/03014223.2001.9517658.
3. D. E. Hurley (1954). "Studies on the New Zealand Amphipodan Fauna. No. 2. The Family Talitridae: The Fresh-Water Genus Chiltonia Stebbing" (PDF). Transactions of the Royal Society of New Zealand. 81 (4): 563–577.
4. Grainger, N.; Harding, J.; Drinan, T.; Collier, K.; Smith, B.; Death, R.; Makan, T.; Rolfe, J. (November 2018). "Conservation status of New Zealand freshwater invertebrates, 2018" (PDF). New Zealand Threat Classification Series. 28: 1–29 – via Department of Conservation.
5. Rachael A. King (2009). "Redescription of the freshwater amphipod Austrochiltonia australis (Sayce) (Crustacea: Amphipoda, Chiltoniidae)" (PDF). Memoirs of Museum Victoria. 66: 85–93.