LIPI Finds Giant Sea Cockroaches In The Sunda Strait

JAKARTA - Researchers from the Indonesian Institute of Sciences (LIPI) have succeeded in describing a new type of giant Bathynomus crustacean, the first from the Indonesian sea.

The location of the discovery is in the Sunda Strait and south of Java Island at a depth of 957-1259 meters below sea level.

The specimens were collected during the South Java Deep Sea Biodiversity Expedition (SJADES) expedition, which is an LIPI expedition with the National University of Singapore with research coordinators Dwi Listyo Rahayu and Peter Ng in 2018.

The discovery of a new type of giant Bathynomus has been published in the journal ZooKeys on July 8, 2020.

The discovery of this new type of giant Bathynomus is considered to be an important scientific achievement, especially in the field of taxonomy which is relatively quiet.

"The discovery of a new species is a major achievement for a taxonomist, let alone a spectacular species in terms of size and even the ecosystem in which these species are found," said the Acting Head of Zoology Division at the Center for Biological Research, LIPI, Cahyo Rahmadi, quoted from the LIPI website, Saturday, July 18.

Cahyo explained that the discovery of this new type reminds us of the huge potential of Indonesia's biodiversity that has not been revealed.

"The future of Indonesia's biodiversity disclosure is catching up with the rate of species extinction and perhaps taxonomy as the front line," said Cahyo.

The choice of the term giant as a type name refers to the size of the body that is included in the category of giant (giant) and very large (super giant) which can reach a size of over 15 centimeters in adulthood.

"It is indeed very large in size and occupies the second largest position in the genus Bathynomus," explained LIPI Biology Research Center researcher Conni Margaretha Sidabalok.

Conni explained, several previous studies had found five types of Bathynomus in the super giant category in the Indian and Pacific Oceans.

"The discovery of the first Bathynomus from the deep sea in Indonesia is very important for taxonomic research on deep sea crustaceans, given the scarcity of similar research in Indonesia," said Conni.

He explained, Bathynomus is one of the icons of deep sea crustaceans with a relatively large size and a distinctive overall appearance.

Bathynomus has a flat and hard body, although it does not have a carapace or hard shell that protects the internal organs of the crustacean body.

The eyes are large, flat, and have a fairly wide gap between them.

The organs on the head are a pair of long antennae, a pair of short antennae at the tip of the head, and the mouth and limbs are modified for feeding in the lower segment of the head.

Bathynomus has seven pairs of walking legs and five pairs of swimming legs.

Identification of the giant Bathynomus was carried out from the male holotype measuring 363 millimeters and female paratype measuring 298 millimeters.

"In general, the giant Bathynomus is most similar to Bathynomus giganteus and Bathynomus lowryi in a range of sizes and characters in the tail or pleotelson," said Conni.

He explained, the differences between the two types are in the characteristics of the antennae, the head organ, surface texture, tail spines and several other characters.

Conni explained that the SJADES expedition also obtained four pre-adult and young Bathynomus specimens from the waters of the Sunda Strait and southern Java.

"We cannot identify these specimens to the species level, because the diagnostic characteristics of the type are usually not developed in the pre-adult stage or at a younger age. But what is certain is that this specimen is not a giant Bathynomus because of the differences in the shape of the tail, side tail and tail spines, "said Conni.