A new species of Lobellina and first record of Vietnura from China (Collembola: Neanuridae: Neanurinae)

Abstract A new species of Lobellina Yosii, 1956 and a key to all species of the genus is provided. It is distinguished from all known members of the genus by its unique set of morphological characters: mandible with six teeth, cephalic chaeta O present, and free from tubercle Fr, cephalic tubercle Oc with three chaetae, cephalic tubercle Di separate, and tubercle Dl with four (sometimes three) chaetae, Ant. I with eight chaetae, and claw with an inner tooth. Vietnuracaerulea Deharveng & Bedos, 2000 is recorded from China for the first time. New localities of Rambutanurahunanensis Jiang & Dong, 2018 and Vitronuraparaacuta Wang, Wang & Jiang, 2016 from southwest China are also provided.


Introduction
Maolan National Nature Reserve is located at Libo County, Qiannan Buyi and Miao Nationalities Autonomous Region of Guizhou Province, southwest China. It covers area of 212.85 km 2 and is located in the subtropical monsoon humid climate zone. The main objectives of Maolan National Nature Reserve are the protection of the karst forest, and its rare animals and plants. It is from 430 to 1078 m above sea level. So far, no Neanuridae was reported from this reserve. During the field research at Maolan National Nature Reserve in 2015, four species of the subfamily Neanurinae were collected. They are described in the present paper.

Materials and methods
Specimens were extracted from soil samples with the aid of Tullgren funnels or directly collected with an aspirator, and preserved in 95% ethanol. They were cleared in Nesbitt's fluid and mounted on slides in Hoyer's medium. Preparations were dried for 7-15 days in oven at 55 °C, then ringed with lacquer. The morphological characters were observed and figures were drawn using a phase contrast microscope Nikon 80i. Material is deposited in Shanghai Entomological Museum, Chinese Academy of Sciences.

General morphology
Ventral chaetotaxy (Fig. 15 and Table 5). On head, groups Vea, Vem and Vep with two, two, two chaetae respectively. Group Vi on head with five chaetae. VT with one proximal and three distal chaetae. On Abd. III, furca rudimentary with 3-4 chaetae, Vel with 3-4 chaetae. On Abd. IV, group Vei, Vec, Vel respectively with one, two, three chaetae, Vl with three or four chaetae. On Abd. V, group Vl with two chaetae, chaeta L' absent, Ag with two chaetae. Anal lobe with twelve chaetae and one mi.
Ecology and distribution. Among fallen leaves of bamboo and under broadleaved trees in the forest. The species is described from Vietnam. In China, it is only known from Maolan National Nature Reserve, Libo County (Fig. 16).
Remarks. Vietnura caerulea is easily distinguished among Chinese Neanurinae by its blue body color, six tubercles on the head, 2+2 pigmented eyes on tubercle Af+Oc, and reduced mandible and maxilla. Additionally, Ve chaetal group of Abd. IV has 3-5 shortened, thickened, and distally ciliated chaetae (male), claw is toothless, and hypotrichosis is developed on body tubercles. Diagnosis. The specimen from Libo County is characterized by its body without long digitate tubercles and tertiary granules, 2+2 depigmented eyes, mandible with four teeth, maxilla styliform, head with eight tubercles (Cl, Af, 2 Oc, 2 Di+De, 2 Dl+L+So), claw with a big inner tooth, and ventral tube with 5-6 chaetae. These characters are similar to those of Rambutanura hunanensis Jiang & Dong, 2018 from Hunan Province; however, the presence of only four chaetae on genital plate reveals the immaturity of the Maolan specimens.
Remarks. The distribution of R. hunanensis is given in Fig. 16. The species has been collected from other localities in China, such as Huping Mountain, Shimen County, Hunan Province (unpublished). It is probably widely distributed in central and southwest China.
Diagnosis. The characters of the specimens from Maolan are consistent with those of Vitronura paraacuta Wang, Wang & Jiang, 2016: body tubercles well differentiated, head with 14 tubercles (only cephalic tubercle L fused to So), 2+2 depigmented eyes, mandible with four teeth, maxilla styliform, tubercles Fr and Oc with three chaetae each, and claw with an inner tooth.
Remarks. The arrangement of the dorsal body tubercles and numbers of chaetae on dorsal tubercles of V. paraacuta are very similar to those of V. dentata Deharveng & Weiner, 1984 from Korea. However, V. paraacuta can be differentiated from V. dentata by almost smooth body macrochaetae, four teeth on mandible, chaetae Di2, De2 on cephalic tubercle De and chaeta Oca on cephalic tubercle Oc being mesochaetae (vs serrated body macrochaetae, three teeth on mandible, chaetae Di2, De2 on cephalic tubercle De and chaeta Oca on cephalic tubercle Oc being microchaetae in V. dentata). The distribution of V. paraacuta is given in Fig. 16.