Nycternyssa dekania dekania ( Verhoeff, 1938 )

Popovici, George, Edgecombe, Gregory D. & Hall, Daniel W., 2024, New Chilopoda from the Chagos Archipelago, Journal of Natural History 58 (41 - 44), pp. 1885-1915 : 1903-1904

Nycternyssa dekania dekania ( Verhoeff, 1938)

( Figure 10 )

Material examined

1 ♀, 81 leg-bearing segments, NHMUK015619678 , Chagos Archipelago, Diego Garcia Island , Minni Minni (beach), 14 May 1971, leg. A.M. Hutson.; 1 ♂, 73 leg-bearing segments, NHMUK015619676 , Chagos Archipelago , Diego Garcia Island, Eclipse Point, 04 April 1971, leg. A.M. Hutson; 1 ♂, 75 leg-bearing segments, NHMUK 1951.12 .11.100, Maldives: Kenurus, Maldive-Laccadive Expedition 1899–1900 .

Remarks

Assignment to Nycternyssa Crabill, 1959 , rather than Orphnaeus Meinert, 1870 , is based on the unipartite female gonopods ( Figure 10 (D)). The Chagos specimens are determined as N. dekania , originally described from a female from Trivandrum (Thiruvanathapum), Kerala, India, based on the posteriorly tapering, trapezoidal sternite of the ultimate leg-bearing segment ( Figure 10 (A)) and the medial contact between the female gonopods ( Figure 10 (A,C); Verhoeff 1942, fig. 9). They are more precisely the nominate subspecies, rather than N. dekania singaporensis ( Verhoeff, 1937) , based on sternal pore areas being limited to a posterior pair only on the penultimate leg-bearing segment ( Figure 10 (A,B)). Short setae clustered immediately anterior to the pore areas are observed in the Chagos specimens ( Figure 10 (B)) as well as the holotype from India ( Verhoeff 1938, fig. 61), and are similarly developed in both sexes. Dense clusters of short setae are also observed adjacent to pore fields on the coxae ( Figure 10 (B)). Although the holotype female of N. dekania dekania has 77 segments, 81 segments are recorded in a female of N. dekania singaporensis , such that the Chagos female is within the known range for the species. We assign a male from the Maldives with 75 leg-bearing segments to N. dekania dekania (collection data cited above), agreeing in all taxonomic characters shared by the Chagos specimens and the type. The subspecies is thus widespread in the Indian Ocean region, its range including at least south-western India, the Maldives and the Chagos Archipelago. It also occurs in the Aldabra atoll in the western Seychelles, for which a full description is in progress by the authors.

Figures

Figure 10. Nycternyssa dekania dekania (Verhoeff, 1938). (A–D) NHMUK015619678. (A) Penultimate and ultimate leg-bearing segments and postpedal segments, ventral view. (B) Sternites and coxae of penultimate and ultimate leg-bearing segments. (C) Ultimate leg tarsus. (D) Female gonopods.