First record of Scolopendrellopsis from China with the description of a new species (Myriapoda, Symphyla)

Abstract The genus Scolopendrellopsis Bagnall, 1913 is recorded from China for the first time and Scolopendrellopsisglabrussp. n. is described and illustrated. The new species is characterized by the short central rod on head, third tergite complete, four kinds of sensory organs present on antenna, and the cerci rather short and covered with a low number of straight setae.


Introduction
There are 204 symphylan species known in the world to date (Szucsich and Scheller 2011;Domínguez Camacho and Vandenspiegel 2012;Bu and Jin 2018); however, only few publications deal with those from Asia. Hansen firstly described five species of Symphyla from Southeast Asia (Hansen 1903). After that several species were described from India (Scheller 1971), Indonesia (Scheller 1988), USSR (Scheller and Golovatch 1982), Russian Far East (Scheller and Mikhaljova 2000) and Iran . Symphyla is poorly studied in China with only Hanseniella caldaria from Zhejiang province and Geophilella orientalis from Hebei province recorded (Zhang and Wang 1992;Bu and Jin 2018). Three genera, Scutigerella, Scolopendrelloides, and Symphylella, were also mentioned for China, but without determined species recorded (Zhang and Wang 1992). During our ecological survey of soil animals of Zhejiang, Jiangsu, and Hainan provinces in recent years, many symphylans were obtained. Among them, one new species of Scolopendrellopsis was identified and is described in the present paper.

Materials and methods
Most specimens were collected during a project for soil animal survey of Gutian Mountain of Zhejiang Province during the years 2012 to 2013; others were collected in Jiangsu province and Hainan province recently. All were extracted by means of the Tullgren funnels from soil and humus samples and preserved in 75% ethanol. They were mounted under slides using Hoyer's solution and dried in an oven at 60 °C. Observations were made with a phase contrast microscope (Leica DM 2500). Photographs were taken by a digital camera installed on the microscope (Leica DMC 4500). Line drawings were drawn using a drawing tube. All specimens are deposited in the collections of Shanghai Natural History Museum (SNHM) and Shanghai Entomological Museum (SEM), Shanghai, China.

Taxonomy
Family Scolopendrellidae Bagnall, 1913 Genus Scolopendrellopsis Bagnall, 1913, new record Diagnosis. Habitus slender. First pair of legs present, 3-segmented and with claws, not more than one-half length of the following pairs. Trunk with 16 or 17 tergites and most of tergites with a pair of posterior processes, without any striped band between each pair of processes on tergites, some tergites transversely divided.
Distribution. The genus Scolopendrellopsis includes fifteen species and is subcosmopolitan, widely distributed in Palaearctic, Nearctic, Neotropical, Ethiopian, Oriental, and Australian regions (Szucsich and Scheller 2011). It is newly recorded from China in this paper.

Scolopendrellopsis glabrus sp. n.
http://zoobank.org/95E5B444-5DEF-49CB-A699-E9730BD69528 Figs 1-3. Tables 1-3 Diagnosis. Scolopendrellopsis glabrus sp. n. is characterized by the short central rod on head, 3 rd tergite not divided and with only weak middle indentation, rod-like sensory organs with setae surrounded on dorsal side of 3 rd -17 th antennal segments, cavityshaped organs on dorsal side of subapical 5-6 antennal segments, mushroom-shaped organs at lateral side of subapical 4-7 segments and bladder-shaped organs on subapical 3-6 antennal segments, first pair of legs longer than the tarsus of the last pair of legs, cerci short and covered with a low number of straight setae. Description. Adult body 1.57 mm long in average (1.45-1.65 mm, n = 8), holotype 1.65 mm ( Figure 1A). Head longer than wide, length 145-175 μm, width 133-170 μm, with widest part a little behind the middle on a level with the points of articulation of mandibles. Central rod distinct and with anterior part absent, length 45-49 μm, approximately one-third of head. Dorsal side of head covered with sparse setae of different length, longest setae (12-17 μm) located at the anterior part of head, approx. 3.0 times as long as central ones (4-5 μm). Cuticle around Tömösváry organ and anterolateral part of head with rather coarse granulation. Central and posterior part of head with dense pubescence (Figs 1B, 3A). (Holotype) A habitus B head, dorsal view C right antenna, 3 th -6 th segments, dorsal view D right antenna, 12 th -16 th segments, ventral view E right antenna, 11 th -16 th segments, dosal view F left Tömösváry organ G stylus on base of 6 th leg (arrow indicated) H stylus on base of 11 th leg (arrow indicated) I first pair of legs J 3 rd leg and coxal sac K 9 th leg and coxal sacs L cerci, dorsal view. ro-rod-like sensory organs with surrounded setae, co-cavity-shaped organ, mo-mushroom-shaped organ, bo-bladder-shaped organ. Scale bars: 100 μm (A), 20 μm (B-L).
Mandible with eleven teeth and divided into two parts by a gap, with five anterior and six posterior teeth respectively. First maxilla has two lobes, inner lobe with four hook-shaped teeth, palp bud-like with two distal points close to outer lobe ( Figure 3B). Anterior part of second maxilla with many small protuberances and posterior part with sparse setae. Cuticle of second maxilla covered with pubescence ( Figure 2A).
Antennae 15-19 segments (16 in holotype), length 250-350 μm (320 μm in holotype), approx. 0.2 of the length of the body. First segment cylindrical, greatest diameter a little wider than long (20-26 μm: 16-25 μm), with four setae in one whorl, the longest seta (6-11 μm) inserted at the inner side and distinctly longer than outer ones (5-8 μm). Second segment wider (20-30μm) than long (18-22 μm), with six or seven setae evenly inserted around the segment and inner setae (6-10 μm) a little longer than outer ones (5-7 μm). Chaetotaxy of 3 rd segment similar to preceding ones ( Figure 3C). Setae on the basal segments 1-3 are slender and on proximal and distal segments rather short. Basal and median parts of the antennae with only primary whorl of setae, in subapical segments one or two minute setae present in secondary whorl ( Figure 3E). Four kinds of sensory organs present on antenna: rod-like sensory organs with setae surrounded present on dorsal side of 3 rd -17 th segments (Figs 1C, 3C, 3D); cavity-shaped organs present on dorsal side of subapical 5-6 segments (Figs 1E, 3D); mushroom-shaped organs present on lateral side of subapical 4-7 segments and bladder-shaped organs on subapical 3-6 segments (Figs 1D, 1E, 3D, 3E). Apical segment subspherical, width 21-22 μm, length 19-20 μm, with 10-12 short setae and wide connection to preceding segment and with two fire-shaped and three baculiform organs present on apex (Figs 1D, 3D, E). All segments covered with short pubescence. Chaetotaxy and sensory organs of antennae are given in Table 1. Trunk: seventeen dorsal tergites present, with 6 th , 9 th , 12 th , and 15 th tergites transversely divided, longer than preceding ones (Figs 2E, 2G, 2H, 2J). Intertergal zones between former and later tergites present, except for 14 th and 15 th , 16 th , and 17 th tergites. Tergites 2 th -13 th and 15 th each with one pair of slender chitinous processes, slightly finger-like. Basal distances between processes are approx. the same length as their length from base to tip, which is longer than its basal width. All tergites pubescent and the margins of apical part of processes ornamented with rowed coarse granules. Apical seta on processes slightly anteriorly located and anterolateral setae slightly longer than other setae. No seta between apical and inner basal setae (Figs 2B-2H).
Etymology. The species name glabrus, meaning bald, to indicate the lower number of setae on cerci.
Distribution. China (Zhejiang, Jiangsu, Hainan). Remarks. Scolopendrellopsis glabrus sp. n. is similar to S. hirta (Scheller, 1971) and S. spinosa (Sheller, 1979) in the shape of 3 rd tergite which is not divided, shape of processes on tergites, shape of sensory organs on antennae. It differs from the latter two species in the absence of anterior part of central rod (anterior part present but indistinct in S. hirta, distinct in S. spinosa), chaetotaxy of the 2 nd and 3 rd tergites (with four and five lateromarginal setae in S. glabrus respectively, five and six in the other two species), cerci with lower number of setae (more setae in S. hirta and S. spinosa), all setae on cerci long and straight (setae on inner side of cerci slightly curved in S. hirta, most setae on cerci short and curved in S. spinosa). It is also similar to the worldwide species S. subnuda in the shape of the first three tergites, number of lateromarginal setae of the 3 rd tergite, shape and number of setae of the cerci, but differs in the absence of anterior part of central rod (anterior part present in S. subnuda), apical seta on processes slightly anteriorly located (rather close to the apex in S. subnuda).