New Evidence Points to Theory Genus May Be 30 Million Years Old
Researchers from the University of Hawai‘i have discovered eight new moth species in the genus Hyposmocoma on three islands within Papah?naumoku?kea Marine National Monument, species found nowhere else in the world. Announcement of the new species was made in October through an article published in Zootaxa, a journal for zoological taxonomists.
The co-authors of the paper, Patrick Schmitz, PhD, and Daniel Rubinoff, PhD, believe these newly discovered species may be descendants of species that colonized the Hawaiian archipelago more than 5 million years ago, before Kaua‘i – the oldest of the Main Hawaiian Islands – emerged. The Northwestern Hawaiian Islands are remnants of islands that at one time rose to 3,000 feet or more in elevation and supported drastically different and more diverse terrestrial plants and animals than are found on the mostly low-lying islands and atolls today. The oldest atoll, Kure, is some 29.8 million years old.
“This is a great snapshot of species endemism, one that indicates how species have evolved on islands throughout the whole archipelago over time,” said Rubinoff. “We are continuing our research now, but it is possible that the ancient ancestor of the now uniquely Hawaiian Hyposmocoma moths may have landed on a young Northwestern Hawaiian and evolved over millions of years into several lineages, which hopped down the chain, spawning a diversity of species.”
“Although only a few of the lineages that were once on the Northwestern Hawaiian Islands are still holding on there now, these tiny atolls, in a former life, were the crucibles of one of the most diverse groups on the current High Islands. The species we described from the Northwestern Hawaiian Islands are the descendents of those original, and likely ancient, Hyposmocoma lineages and they have hung on, adapting over time to the islands’ current severe dry conditions. They are the survivors,” he continued.
Hyposmocoma moths are found only in the Hawaiian Islands and include more than 315 different species. Along with picture-wing flies (Drosophila species), they are the most diverse animal genus within the state. Prior to this study, only one species of Hyposmocoma had been identified in the Northwestern Hawaiian Islands, H. neckerensis, described in 1926 from Mokumanamana.
“I am certain more species are waiting to be discovered in the Monument, since we’ve found hard evidence of their caterpillars and know them to be unique,” said Rubinoff. “We also know that Gardner Pinnacles has at least one endemic species and possibly more, but we just haven’t been able to get there yet to document it.”
All of the native Hyposmocoma moth species in Hawai‘i are small, with most only having a wingspan of less than 0.4 inches. Many of the Hyposmocoma species, including all eight new species, feature varying shaped cases used as shelters by their larvae. In the Main Hawaiian Islands, Hyposmocoma is most diverse in species numbers in wet forest, and some species are even found in aquatic habitats, so finding so many diverse species in the harsh dry conditions of the small and isolated Northwestern Hawaiian Islands is surprising, according to Rubinoff.
The moths identified in this study were reared from larvae collected on Laysan Island, Mokumanamana, and Nihoa in 2004, 2007, and 2008. No Hyposmocoma moths were found on Midway Atoll despite intensive fieldwork. The new species are:
• Hyposmocoma laysanensis, named after and found only on Laysan Island
• Hyposmocoma ekemamao, a larger species found only on Laysan and named for its purselike case (eke in Hawaiian) and the island’s remoteness (mamao in Hawaiian)
• Hyposmocoma opuumaloo, found only on Mokumanamana and named from the Hawaiian pu‘u, cone, and malo‘o, dry, referring to its cone-shaped case and the island’s dry habitat (most cone-cased species in the Main Hawaiian Islands are aquatic)
• Hyposmocoma mokumana, found on Mokumanamana and named for the island
• Hyposmocoma nihoa, found on Nihoa and named for the
• Hyposmocoma kikokolu, found on Nihoa and named from the Hawaiian kiko, spot, and kolu, three, referring to the three spots on its forewing
• Hyposmocoma menehune, found on Nihoa and named for the nocturnal Hawaiian legendary menehune
• Hyposmocoma papahanau, found on Nihoa and named after Papahanaumokuakea
Papah?naumoku?kea is cooperatively managed to ensure ecological integrity and achieve strong, long-term protection and perpetuation of Northwestern Hawaiian ecosystems, Native Hawaiian culture, and heritage resources for current and future generations. Three co-trustees – the Department of Commerce, Department of the Interior, and State of Hawai‘i – joined by the Office of Hawaiian Affairs, protect this special place, which is now being considered for inscription as a UNESCO World Heritage Site. For more information, please visit /www.papahanaumokuakea.gov
Note to Reporters: One of the authors, Daniel Rubinoff, has graciously made himself available for interviews. You may reach him in Honolulu at (808) 956-8432.
