Sinomicrurus iwasakii

Sinomicrurus iwasakii, the Iwasaki's temperate Asian coralsnake, is a rare species of coral snake from the Ishigaki and Iriomote islands of the Yaeyama Group, Ryukyu Archipelago, Japan. S. iwasakii belongs to the family Elapidae which also includes cobras and sea snakes.

The International Union for the Conservation of Nature (IUCN) Red List does not include S. iwasakii as a species despite species status as of 2021. Other similar Sinomicrurus species are listed as "Unknown" conservation status.

Taxonomy

Sinomicrurus iwasakii was originally described as Calliophis iwasakii by Maki in 1935. It was long thought to be a subspecies of S. macclellandii but was revalidated as a species in 2021 by Smart, Ingrasci and colleagues.

Sinomicrurus iwasakii is part of the "banded" clade shown in Figure 3 of Smart et al. and is most closely related to S. swinhoei from Taiwan. Phylogenetic analysis shows that these two form a distinct and strongly supported lineage, with a posterior probability of 1.00, indicating a high level of confidence in their shared ancestry. This relationship is consistent across both the traditional tree and the Bayesian cloudogram, where the two species cluster tightly together. Their close genetic connection suggests a recent common ancestor and highlights a likely biogeographic link between the Ryukyu Islands and Taiwan, potentially shaped by historical dispersal or land bridge events.

Etymology

The genus Sinomicrurus is derived from the Chinese word sino, meaning "China", and from the Greek mikros, meaning "small", and oura, meaning "tail".

The species is named after Takuji Iwasaki (1869-1937), the chief meteorologist and honorary citizen in Ishigaki-jima. Takuji made major contributions to biology, especially through his work identifying new species. A Japanese article refers to him as, a pioneer in the study of the southern islands.

He identified and named several insects, and raised butterflies such as the Oogomadara (Idea leuconoe), also known as the rice paper or paper kite butterfly, and the Konoha Cho, observing their behavior closely. The Oogomadara is originally from Southeast Asia and is well known for being displayed in butterfly houses.

In herpetology, aside from Iwasaki's coral snake, the Iwasaki Sedaka Hebi (Pareas iwasakii) was named in his honor. Along with his butterflies he raised venomous snakes like the Sakishima habu (Protobothrops elegans) and developed methods for handling them safely.

Common names include Iwasaki's temperate Asian coralsnake, Iwasaki's Korallenotter (German), and in Japanese Iwasaki-monbeni-hebi.

Biology

Description

Sinomicrurus iwasakii is a small species of snake, with most adults measuring between 23 and 33 cm (9 to 13 in) long. Females are usually a little bigger than males. The largest individuals recorded were around 33.5 cm (13.2 in), but snakes this size are rare. On average, males are about 27.2 cm (10.7 in) long, and females about 28 cm (11 in). These snakes are also very light, typically weighing less than 100 grams (3.5 oz).