Sympetrum dilatatum (St Helena Dragonfly)

[Melanie]

St Helena dragonfly Sympetrum dilatatum (EX):
this species has not been seen with certainty since
1963 and is considered to be extinct in the 1996
IUCN red list of threatened animals (IUCN
1996).

[another specialist]

also known as ST. HELENA DARTER

[another specialist]

EX

www.redlist.org/search/details.php?species=21226

[another specialist]

melanie said:

St Helena dragonfly Sympetrum dilatatum (EX):
this species has not been seen with certainty since
1963 and is considered to be extinct in the 1996
IUCN red list of threatened animals (IUCN
1996).

source for above

www.jncc.gov.uk/pdf/OT_StHelena.pdf

[Melanie]

Last seen in 1977, this species is thought to have been extirpated by a combination
of factors, including impacts from an alien frog.

Source: Freshwater Ecoregions of Africa and Madagascar (books.google.de/books?id=3nkL9NqqlscC&printsec=frontcover&dq=Freshwater+Ecoregions+of+Africa+and+Madagascar&hl=de&sa=X&ei=FtdUT6iEIujR4QSe0eysDg&redir_esc=y#v=onepage&q=dilatatum&f=false)

[another specialist]

www.asahi-net.or.jp/~CH2M-NITU/tombo.htm

[Melanie]

Philip Powell Calvert's original description of Diplax dilatata (=Sympetrum dilatatum) (1893)

www.biodiversitylibrary.org/page/15780948#page/736/mode/1up

[koeiyabe]

"Lost Animals (in Japanese)" by WWF Japan (1996)

[Sebbe]

The St. Helena Darter was endemic to St. Helena Island. There are very few published records of the species. The type series (four males, one female) was collected during the U.S. Solar Eclipse expedition between 20th February and 10th March 1889–1890 (Calvert 1892, 1894; Ris 1911, Stearns 1894). The last known record (a female) was collected at Green Hill in October 1963 (Pinhey 1964). Because there were no records since then, the species was originally assessed as Extinct. But since there was never a systematic survey for the species after 1963 it was later reassessed as Data Deficient (in 2011). After that there have been several focused surveys on St. Helena by Buglife, which have never encountered a libellulid dragonfly or dragonfly larvae. Therefore, the species was reassessed as Critically Endangered (Possibly Extinct) in 2018. With the following information provided by David Pryce in December 2020 we now declare the St. Helena Darter as extinct, most likely as an effect of invasive frogs.
David Pryce, December 2020: "With regards to Sympetrum dilatatum, I can confirm that it is certainly extinct. I have lived on St Helena for nearly eight years and haven't seen it, despite driving past a perfect piece of habitat while going to and from work for seven of these, as well as keeping a general look-out for it while I am out and about, plus general asking around, especially among the conservation community. All I hear whenever I am in suitable habitat is the invasive, non-native frog Strongylopus grayii pinking away in the undergrowth with large tadpoles often visible in stream pools."

www.iucnredlist.org/species/21226/193512121#assessment-information