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| Eudigraphis huadongensis Yang & Bu, in Yang, Bu, Godeiro, Gao et Jin, 2025. |
Abstract
Eudigraphis huadongensis Yang & Bu, sp. nov. from east China is described and illustrated. The new species is compared with other congeners in detail and observations about its embryonic and post-embryonic development are provided. The complete mitochondrial genome of the new species is also analyzed, which represents the first published mitogenome of Polyxenida. The genetic divergence between E. huadongensis sp. nov. and its congeners was analyzed using Neighbor-Joining inference based on COI gene sequences. Eudigraphis huadongensis sp. nov. clustered with E. nigricans and E. kinutensis, supporting the morphological identification. The newly assembled mitogenome is 15,206 bp in length and its gene order is unique, possibly representing a pattern among Polyxenida species.
Key words: Bristle millipedes, mitochondrial genome, molecular analysis, taxonomy, stadium
Class Diplopoda de Blainville in Gervais 1844
Subclass Penicillata Latreille, 1831
Order Polyxenida Verhoeff, 1934
Family Polyxenidae Lucas, 1840
Subfamily Monographinae Condé, 2008
Genus Eudigraphis Silvestri, 1948
Type species. Eudigraphis japonica Silvestri, 1948 (= Eudigraphis takakuwai);
type locality: Ehime-ken and Kanagawa of Japan.
Diagnosis. Head with eight ommatidia on each side. Body with ten segments, nine pleural projections, a telson, and 13 pairs of legs. Antenna with eight articles, the sixth antennal article has three long bacilliform sensilla, some species also have one conical sensillum and one setiform sensillum; the seventh antennal article has two long bacilliform sensilla, some species also have one conical sensillum and one setiform sensillum; eighth antennal articles is shorter than article VII, with four finger-shaped sensory cones. Tergites with two lateral clusters of trichomes plus a single continuous row of trichomes close to posterior edge. Caudal trichomes on telson arranged as a penicil of hooked and barbate trichomes. The mandible has a comb-lobe, an intermediate plate, and a proximal plate, without a molar tuft.
Distribution. China (Jiangsu, Shanghai, Taiwan, Yunnan, Zhejiang), Japan.
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| Live specimen of Eudigraphis huadongensis sp. nov. |
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| Embryonic development of Eudigraphis huadongensis sp. nov. A. Adults and eggs; B. Eggs protected by caudal trichomes; C, D. Embryo of two weeks; E. Embryos with ommatidia pigments present; F. Embryos observed in the fourth week; G. Embryos and new-hatched juvenile; H. Juveniles of stadium I after 2 days; I. Juvenile of stadium I, showing brown caudal bundle. |
Eudigraphis huadongensis Yang & Bu, sp. nov.
Diagnosis. Eudigraphis huadongensis sp. nov. is characterized by three long bacilliform sensilla, one conical sensillum and one setiform sensillum on the sixth antennal article, two long bacilliform sensilla, one conical sensillum and one setiform sensillum on seventh antennal article; posterior vertex trichome groups with 11–16 sockets in anterior row and 7–13 sockets in posterior row; 12 slender sensilla on lateral palp of gnathochilarium and 20 or 21 conical sensilla on the medial palp; 2+2 lamellae and 5+5 clypeo-labral setae on the labrum. The mandible has 14 branched comb teeth, ten rows of simple comb teeth, three longitudinal groups of intermediate sensilla, 14 serrate limbs, one smooth limb, 13 salivary ostioles, seven molar processes and seven molar combs. The leg setae have a coniform pleated base. The telson has 11–17 ornamental trichomes on each side dorsal to the caudal bundle; hooked caudal trichomes with a maximum of eight hooks.
Etymology. The species was named after the Chinese words “Huadong” = “East China” which is the region where all type specimens were collected.
Si-Qi Yang, Yun Bu, Nerivania Nunes Godeiro, Yan Gao and Ya-Li Jin. 2025. A New Species of Eudigraphis (Diplopoda, Polyxenida, Polyxenidae) from East China, with embryonic and post-embryonic development observations, and mitogenomic and genetic divergence analyses. ZooKeys. 1247: 63-88. DOI: doi.org/10.3897/zookeys.1247.155348
