A new genus of japygids (Diplura: Japygidae) in mid-Cretaceous amber from northern Myanmar Author Wang, Ye-Hao State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China & University of Chinese Academy of Sciences, Beijing 100049, China Author Huang, Di-Ying State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China Author Cai, Chen-Yang State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China text Zootaxa 2023 2023-12-29 5396 1 64 73 https://www.mapress.com/zt/article/download/zootaxa.5396.1.12/52605 journal article 283450 10.11646/zootaxa.5396.1.12 55e437d8-b2f5-4ffb-8ad0-2a9dd495048a 1175-5326 10441195 EBC29EC0-BB77-46F1-A715-B8724796741F Cretojapyx huangi sp. nov. Figs 1–5 Material. Holotype , genitalia not visible, developmental stage and gender unknown, NIGP203387 . The amber specimen generally yellow and relatively transparent, with many bubbles inside and some around C . huangi . Etymology. The specific epithet ‘ huangi ’ is dedicated to the famous entomologist, Fusheng Huang, who made remarkable discoveries of Gigasjapyginae in China with Prof. Yao Zhou, and presented the extant japygids for our study. Diagnosis. As for the genus. Locality and horizon. Amber mine located near Noije Bum Village , Tanai Township , Myitkyina District , Kachin State , northern Myanmar ( 26°15′N , 96°36′E ); upper Albian to lower Cenomanian , mid-Cretaceous . FIGURE 1. General habitus of Cretojapyx huangi gen. et sp. nov. A , Ventral view. B , Dorsal view. Scale bars = 1 mm. FIGURE 2. Antenna and thorax of Cretojapyx huangi gen. et sp. nov. A , Antennae, red triangulars indicating 10 th , 20 th and 30 th antennomeres. B–D , M chaetotaxy on the pronotum, mesonotum and metanotum. Scale bars = 0.2 mm. Description. Body elongated, ca . 9.9 mm in length from the forefront of head the end of abdominal segment X ( Fig. 1A, B ). Abdominal segment I–VII with nearly parallel sides and narrowing from the segment VIII. Body surface smooth under optical microscope, with s, sM, M. Cuticle unpigmented, with lacinia apex; dorsal head, abdominal segment VIII–X and cerci sclerotized ( Fig. 1A, B ). Antennae ca . 3.2 mm in length, 0.3× as long as body, the left antenna with 38 antennomeres, the right with 39 ones ( Fig. 2A ); antennomeres telescopic, 2 nd antennomere longest, 1.6× as long as wide. All antennomeres covered dense s and macrosetae; 3 rd –5 th antennomeres with several long macrosetae ( Fig. 2A ). Distribution pattern of trichobothria and placoid sensilla not observed due to decay of antennal surface. Head covered with s, sM and M dorsally; Ventral side with less setae and macrosetae, admentum with 12+12 macrosetae, mentum with 2+2 macrosetae ( Fig. 5A ). Maxillary palps with some macroseta on the distal half ( Fig. 5B ). Labial palps elongated and tapering towards the distal, with 1 proximal, 5 medial and 2 distal macrosetae. Lacinia apex sharp, curved inwardly and sclerotized strongly ( Fig. 5B ). Thoracic segment I shortest, gradually elongatated towards segment III. Thorax contracted, prescuta not visible; pronotum with 4+4M1–4 ( Fig. 2B ), mesonotum and metanotum each with 5+5 M1–5 ( Fig. 2C, D ), Ventral side of thorax significantly decay, the structures anterior to the meta-intersternum indistinct, Y-shaped cuticular structure in the metasternite visible. Legs normal, dorsal side with numerous s, sM and M. Tarsus with 2 rows of setae ventrally, 8 setae in each row ( Fig. 5F ); hind leg ca . 2.1 mm , reaching middle of segment IV. Pretarsus with 2 unequal claws and 1 short and sharp medial unguiculus; the posterior claw 1.3× than the length of the anterior ( Fig. 5G ). FIGURE 3. Chaetotaxy of M on urotergites Ⅰ–VIII of Cretojapyx huangi gen. et sp. nov. Scale bars = 0.2 mm. Abdominal tergites with M and a few sM. Abdomen contracted, prescuta not visible. Urotergite I with 2+2 macrosetae (M1, M5) ( Fig. 3A ); urotergite II, VI each with 4+4 macrosetae (M1–2, M4–5) plus 1 anterior lateral M ( Fig. 3B, F ); urotergite IV with 5+5 M1–5 ( Fig. 3D ); urotergite III, V each with 6+6 M ( Fig. 3C, E ); urotergite VII with 2+2 (M2, M5) ( Fig. 3G ); urotergite VIII with 2+2 (M4, M5) ( Fig. 3H ). Segment X 1.4× as long as wide, with distinct carinae; carinae subparallel and converging towards the posterior margin of the segment X until disappearing; dorsal side with 2+2 M between the carinae; acropygium round. Urotergite VII protruding backward, forming pointed angles and each with 1 macroseta ( Fig. 5H ). Urosternites with dense macrosetae. Median glandular organ invaginated ( Fig. 5D ), lateral subcoxal organ with 1 row of glandular seta ( Fig. 5E ); lateral subcoxal organ occupying 0.3× of interstylar area. Styli tapering towards apex ( Fig. 5E, I ). Cerci asymmetric, ca . 0.96 mm in length, slightly shorter than Segment X ( ca . 1 mm ); basal 2/3 of lateral margin straight and curved inward rapidly in the distal, the distal 1/3 slightly upward, end sharp and hook-like ( Fig. 4A ); carinae arising from the dorsal and ventral acetabular articulations and disappearing at the basal 2/3 ( Fig. 4A ). Right cercus with 1 postmedial tooth; predental margin slightly concaved near the tooth, postdental margin with a row of at least 10 small round denticles gradually decreasing in size until disappearing before the hook ( Fig. 4C ). Left cercus slenderer than the right and strongly concaved in the distal 1/3 of inner margin, relatively smooth without distinct tooth or denticles ( Fig. 4B ).