Sunday, January 15, 2023

[Diplopoda • 2023] Spirobolus akamma • Taxonomic Assessment of A Threatened Large Millipede Endemic to the Southern Ryukyu Islands, Japan: A New Species of Spirobolus (Spirobolida: Spirobolidae) from the Yaeyama Islands

 

Spirobolus akamma
 Kato, Takano, Nakano & Shimano, 2023

 
Abstract
The taxonomic status of millipedes of the genus Spirobolus Brandt, 1833, referred to as “Yaeyama-maruyasude” from the Yaeyama Islands, Ryukyu Islands, Japan, was unresolved. We assess the taxonomic status of these Yaeyama Spirobolus sp. using an integrated morphological and molecular approach, and describe them as a new species, Spirobolus akamma sp. nov., for which partial sequences of the nuclear 28S ribosomal RNA, mitochondrial cytochrome c oxidase subunit I, and 16S ribosomal RNA markers are provided. This new species differs from continental China and Taiwan endemic congeners in anterior gonopod morphology (in having an elongate and subtriangular coxa, and a pentagonal mesal sternal process), posterior gonopod morphology (in having a coronoid prefemoral endite with rounded distal end, and an elongate telopodite), and in having four serrations on the cyphopod lateral flange.

Keywords: Myriapoda, Juliformia, arboreal, threatened species, SEM images


Spirobolus akamma sp. nov., holotype male (KUZ Z4329; B–D).
 B, dorsal view; C, lateral view; D, ventral view.

Spirobolus akamma sp. nov., an individual from near the Mariudo Waterfall, Iriomote Island.
(photograph taken by N. Sawada)

Taxonomy 
Family Spirobolidae Bollman, 1893 
Genus Spirobolus Brandt, 1833 

Spirobolus akamma sp. nov. 
[Japanese name: Yaeyama-maruyasude]

Diagnosis. The new species is characterized by the following combination of characteristics: coxa of anterior gonopods long and subtriangular; mesal sternal process of anterior gonopods pentagonal; prefemoral endite of posterior gonopods coronoid, distal end rounded, with mesal margin lacking notch; telopodite of posterior gonopods more than 2× longer than prefemoral endite; lateral flange of cyphopods with 4 serrations.

Etymology. The specific name akamma is derived from the Yaeyama folk tale “赤馬” (Akamma means “red horse” and is the name of the horse beloved by the protagonist), and thus is treated as indeclinable.

 
 Taiga Kato, Mitsuo Takano, Takafumi Nakano and Satoshi Shimano. 2023. Taxonomic Assessment of A Threatened Large Millipede Endemic to the Southern Ryukyu Islands, Japan: A New Species of Spirobolus (Diplopoda: Spirobolida: Spirobolidae) from the Yaeyama Islands. Species Diversity. 28(1); 23-30. DOI: 10.12782/specdiv.28.23 

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