First record of the family Colinauropodidae (Myriapoda, Pauropoda) in China, with the description of three new species

Abstract The pauropod family Colinauropodidae Scheller, 1985 is recorded from China for the first time. Three new species of the genus Colinauropus Remy, 1956 are described: Colinauropus chinensissp. nov. and C. chongzhouisp. nov. from Jiangsu Province, and C. foliosussp. nov. from Sichuan Province. They can be easily separated from similar species by the number and the shape of sclerotized plates on the tergites, setae on the body and the anal plate. A key for all species of the genus is provided.

In the original description, the genus Colinauropus was considered to be affiliated with species of the family Brachypauropodidae Silvestri, 1902 according to the fragmented tergites and the shape of anal plate (Remy 1956). Its taxonomic position was reconsidered and placed in the family Pauropodidae Lubbock 1867, under the new subfamily Colinauropodinae, which was supposed to be closely related to the subfamily Scleropauropodinae (Scheller 1985). In the latest classification system, the subfamily Colinauropodinae was upgraded to family Colinauropodidae (Scheller 2009(Scheller , 2011. The purposes of this study are 1) to record the occurrence of family Colinauropodidae Scheller, 1985 in China for the first time; 2) to describe three new species of the genus Colinauropus Remy, 1956 from China;3) to give a key to the species of the genus.

Materials and methods
All pauropods were collected using a Tullgren's funnel. The specimens were sorted under a stereomicroscope and preserved in 80% alcohol. They were mounted on slides using Hoyer's solution and dried in an oven at 50 °C. Observations were performed under a phase contrast microscope (Leica DM 2500). Photos were taken using a digital camera (Leica DMC 4500). Line drawings were made using a drawing tube. All specimens were deposited in the collection maintained by the Shanghai Natural History Museum.
Abbreviations used in the descriptions follow Qian et al. (2018). Absolute lengths of all other body parts are given in mm and μm. Otherwise, the text refers to relative lengths. For the description of the new species, measurements and indices of paratypes are given in brackets.
Anal plate linguiform, glabrous, 2.0 times longer than broad, lateral margins concave in anterior part, posterior margin with three small lobes; two pairs of appendages present: inner one tiny and conical; outer one cylindrical and longer, (0.4-) 0.5 of the length of plate and with short pubescence (Figs 1G, 2L).
Etymology. The species is named after China where the type specimens were collected.
Distribution. China (Jiangsu). Only known from the type locality. Remarks. Colinauropus chinensis sp. nov. is most similar to C. haginoi Scheller, 2009 from Philippines in the similar shape of the anal plate and absence of sclerotized plates on tergite I. They can be easily distinguished by the number of sclerotized plates on tergites II and VI (6 and 2 in C. chinensis sp. nov., vs. 8 and 4 in C. haginoi), length of setae on collum segment (sublateral setae 1.9-2.0 times as long as submedian setae in C. chinensis sp. nov. vs. 3.2 times in C. haginoi), and the shape of T 3 (subcylindrical, not clavate in C. chinensis sp. nov. vs. proximal half distinctly clavate in C. haginoi). Diagnosis. Colinauropus chongzhoui sp. nov. is characterized by the slender, annulate-striate setae on head, antennae and tergites; tergite I with 1 large sclerotized plate; tergite II with 6 small and 2 large sclerotized plates; tergites III-V each with 4 large and 4 small plates; tergite VI with 2 large plates; seta st on tergum of pygidium clavate; bothriotrichum T 3 brush-shaped, with branched pubescence distally.
Anal plate linguiform, 1.7 times longer than broad; a pair of clavate appendage inserted posteriorly, 0.4 of the length of plate, and with short pubescence (Figs 4G, 6A).
Etymology. The species is dedicated to the honor of the late Professor Chongzhou Zhang  who was an eminent zoologist from Institute of Zoology, Chinese Academy of Sciences, for his great contribution to the knowledge of Myriapoda of China (Stoev et al. 2014).
Distribution. China (Jiangsu). Only known from the type locality. Remy, 1956 in the shape of anal plate. They can be easily distinguished by the number of sclerotized plates on tergite I (1 large plate in C. chongzhoui sp. nov. vs. 2 in C. regis) and tergite II (8 in C. chongzhoui sp. nov., vs. 6 in C. regis), shape of setae on tergites (slender and striate in C. chongzhoui sp. nov. vs. clavate and pubescent in C. regis), and the shape of seta a 1 on pygidium (tapering in C. chongzhoui sp. nov. vs. clavate in C. regis).
Diagnosis. Colinauropus foliosus sp. nov. is characterized by the leaf-shaped pubescent setae on head and tergites; tergite I with one large sclerotized plate; tergites II-IV each with 4 large and 4 small plates; tergite V with 4 large and 2 small middle sclerotized plates; tergite VI with 2 large plates; granules on plates ovoid, each inserted with one fine hair; seta st on tergum of pygidium clavate; bothriotrichum T 3 with thick axis and dense tufted pubescence distally.
Male genital papillae (Fig. 9E) glabrous, subuliform, 1.5 times as long as greatest diameter; seta 0.5 of the length of papilla. Seta on coxa of leg 2 in male with two adjacent setae (only 1 thick setae in female, 20-25 μm), both cylindrical and annulate, one thick and short, 17 μm in length, another slender and longer, 20 μm in length (Fig. 9E).
Anal plate round, glabrous, 1.5 times longer than broad, lateral margins bulged in middle part, posterior part divided into two round, pubescent branches, two tiny lobes present at inner side (Figs 7G, 8L).
Etymology. The species name "foliosus" from the Latin "foliose", leaf-shaped, referring to the leaf-shaped setae on head and tergites.
Distribution. China (Sichuan). Only known from the type locality. Remarks. Colinauropus foliosus sp. nov. differs from all other congeners by having 6 sclerotized plates on tergite V, and the posterior two square-shaped, compared with 4 or 8 irregular plates in congeners. It is similar to C. regis Remy, 1956 in the leaf-shaped setae on tergites, but they can be easily distinguished by the number of sclerotized plates on tergite I and II (1 and 8 in C. foliosus sp. nov. vs. 2 and 6 in C. regis), shape of the setae in the posterior two rows of the head (leaf-shaped in C. foliosus sp. nov. vs. cylindrical in C. regis), and the shape of anal plate (with two round posterior branches in C. foliosus sp. nov. vs. with two clavate appendages in C. regis).
Key to the species of the genus Colinauropus Remy, 1956

Discussion
The genus Colinauropus Remy, 1956 is well defined by the presence of sclerotized plates on the tergites. The number of plates on tergites I, II, V and VI, which varies from 1 to 8, are good characters for species identification, while tergites III and IV always have 8 plates in all species. The shape and arrangement of the plates are also taxonomically informative for species definition. On tergite I, the plates are absent or at most with small patches of thickened cuticle posteriorly (C. haginoi, C. chinensis sp. nov.), with 1 complete large plate (C. chongzhoui sp. nov., C. foliosus sp. nov.) or with 2 axially separated plates (C. regis, C. schelleri). On tergite II, 4 small anterior plus 2 large posterior plates are present in C. regis and C. chinensis sp. nov., 6 small anterior plus 2 large posterior plates are present in C. chongzhoui sp. nov., while there are 4 small plus 4 large plates in the remaining three species. On tergite V, the number of plates can be 4 in C. schelleri, 4 large plus 2 small middle plates in C. foliosus sp. nov., and 4 large plus 4 small plates in others.
On tergite VI, all species have 2 large plates, except C. haginoi which has 4 plates. The shapes of plates are usually ovoid, round, sub-triangular, or irregular, while the two pos-terior large plates on tergite V are nearly square-shaped in C. foliosus sp. nov. Variation of plates within a species has never been reported in former studies but is observed here in C. chongzhoui sp. nov., which exhibits 2 plates on tergite I in juveniles vs. 1 complete plate in adults. Thus, caution is advised when describing species of this genus, which should be based on fully mature specimens. As an additional taxonomic character, the bothriotrichum T 3 is also well differentiated and nicely separates species. The most informative characters are the shape and appendages of the anal plates. The six known species of the genus Colinauropus Remy, 1956 can be distinguished by the key provided above.