Monday, September 28, 2015
Deep in the sediments of Kaua`i’s Makauahi sinkhole is evidence of an entire collection of insects, lost in time and now extinct.
They represent some of the diverse life forms of the Hawaiian lowland forest that once spilled from the foothills of Ha`upu mountain.
The beetles are in the genus Blackburnia, and help fill in missing pieces in the evolution of the Islands, according to anarticle in the journal Invertebrate Systematics, by James K. Liebherr and Nick Porch, of Cornell University and Australia’s Deakin University, respectively.
“The addition of extinct Kauai species to clades previously known only from extant species on Maui Nui and Hawaii Island reinforces the biogeographic pattern of progressive colonization by Blackburnia beetles from older Hawaiian islands to younger,” they write.
The paper is entitled “Reassembling a lost lowland carabid beetle assemblage (Coleoptera) from Kauai, Hawaiian Islands.”
The new findings link known species of beetles from ancient Laysan Island to young Hawai`i Island.
Scientists had some fun with naming the new species. They are Blackburnia burneyi, B. cryptipes, B. godzilla, B. menehune, B. mothra, B. ovata and B. rugosa.
Several of the newly named species are significantly larger than any of the living relatives on Kauai, which explains their names. B. godzilla is the biggest of all, and mothra is another big one.
The first, B. burneyi, is named for David A. Burney, who led the excavation of the famous south Kaua`i limestone feature known as Makauahi. His wife and partner, Lida Pigott Burney helps manage the cave reserve.
For more information on the amazing sinkhole and associated caves, and the program to re-establish many of the native plant species that once existed on this landscape, see http://cavereserve.org/. (If you like what they'd doing, please consider sending a donation.)
The beetles are believed to have gone extinct largely because of human-caused destruction of their habitat. The beetle parts were found in sediments dated to before the arrival of Polynesians in the Islands, and they disappear from sediments soon after.
“Seven of the species discovered in these deposits are not known from any historically collected specimens, supporting the conclusion that these species suffered extinction through the agencies of Polynesian agricultural land conversion and introduction of invasive predators such as the Pacific rat,” the paper says.
The authors of the paper don’t believe they have yet collected enough material to be able to describe all of the insects of this prehistoric South Kaua`i habitat, but there’s a suggestion more may be learned.
“We do not claim to have an accurate representation of the lowland carabid fauna of Kauai that was destroyed through the agencies of man. But now that there are fossils, there are some interesting tales to tell,” they write. Carabids are part of a global family of fast-moving ground beetles.
© Jan TenBruggencate 2015