Symphylella communa Jin & Bu, 2020

Jin, Ya-Li & Bu, Yun, 2020, Two new species of the genus Symphylella (Symphyla, Scolopendrellidae) from East China, ZooKeys 1003, pp. 1-18 : 1

Symphylella communa Jin & Bu sp. nov. Figures 4 , 5 , 6 , Tables 4, 5, 6

Diagnosis.

Symphylella communa sp. nov. is characterized by the chaetotaxy of the first tergite composed by 4+4 setae, processes of tergites somewhat longer or the same length with broad, most of lateralmaginal setae long, anterolateral setae of tergites 2-4, 6, 7, 9, and 10 distinctly longer than other lateromarginal setae, approximately as long as processes of the same tergite, cerci with numerous subequal and slightly curved setae.

Material examined.

Holotype, male (slide no. SH-DJS-SY2015048) (SNHM), China, Shanghai, Dajinshan Island, extracted from soil samples of broad-leaf forest, alt. 103 m, 30°41'N, 121°26'E, 30-VI-2015, coll. Y. Bu & Y. L. Jin. Paratypes, 1 male (slide no. SH-DJS-SY2015023) (SNHM), 10 females (slides no. SH-DJS-SY2015001, SH-DJS-SY2015018-SH-DJS-SY2015022, SH-DJS-SY2015024, SH-DJS-SY2015025, SH-DJS-SY2015048, SH-DJS-SY2015055) (SNHM), same data as holotype; 2 males (slides no. SH-DJS-SY2015099, SH-DJS-SY2015108) (SNHM), 1 female (slide no. SH-DJS-SY2015107) (SNHM), ibidem, 22-IX-2015; 4 males (slides no. SH-DJS-SY2015083, SH-DJS-SY2015124, SH-DJS-SY2015125) (SNHM), 5 females (slides no. SH-DJS-SY2015058, SH-DJS-SY2015059, SH-DJS-SY2015079, SH-DJS-SY2015122, SH-DJS-SY2015123) (SNHM), ibidem, extracted from soil samples of bamboo forest, 22-IX-2015, coll. Y. Bu & Y. L. Jin; 5 females (slides no. SH-DJS-SY2015117, SH-DJS-SY2015118, SH-DJS-SY2015120, SH-DJS-SY2015121) (SNHM), ibidem, extracted from soil samples of broad-leaf forest, 22-IX-2015, coll. Y. Bu & Y. L. Jin; 1 female (slide no. ZJ-GTS-SY2012018) (SNHM), 1 male (slide no. ZJ-GTS-SY2012009) (SNHM), Zhejiang, Gutian Mountain, extracted from soil samples of broad-leaf forest, alt. 800 m, 29°15'N, 118°06'E, 11-IV-2012, coll. Y. Bu et al.; 1 male (slide no. ZJ-GTS-SY2012021) (SNHM), ibidem, 16-V-2012; 1 female (slide no. ZJ-GTS-SY2012041) (SNHM), ibidem, 19-VI-2012; 1 female (slide no. ZJ-GTS-SY2012045) (SNHM), ibidem, 14-X-2012; 1 female (slide no. ZJ-GTS-SY2012054) (SNHM), ibidem, 17-XI-2012, coll. Y. Bu et al.; 4 females (slides no. JS-WX-SY2017012, JS-WX-SY2017017, JS-WX-SY2017018, JS-WX-SY2017033) (SNHM), 1 male (slide no. JS-WX-SY2017035) (SNHM), China, Jiangsu, Wuxi, Daji Mountain, extracted from soil samples of broad-leaf forest, alt. 5 m, 31°32'N, 120°12'E, 9-X-2017, coll. Y. Bu. Non-type specimens: 37 juveniles with 7-10 pairs of legs, same data as holotype; 6 juveniles with 7-10 pairs of legs, ibidem, 22-IX-2015; 32 juveniles with 7-10 pairs of legs, 22-IX-2015; 8 juveniles with 7-10 pairs of legs, 23-IX-2015, ibidem, extracted from soil samples of bamboo forest, 22-IX-2015, coll. Y. Bu & Y. L. Jin; 1 juvenile with 9 pairs of legs (slide no. ZJ-GTS-SY2012011), Zhejiang, Gutian Mountain, 11-IV-2012; 1 juvenile with 9 pairs of legs, ibidem, 19-VI-2012; 4 juveniles with 8 pairs of legs, ibidem, 15-VII-2012; 1 juvenile with 9 pairs of legs, ibidem, 19-IX-2012; 3 juveniles with 8 or 10 pairs of legs, ibidem, 14-X-2012; 3 juveniles with 8-10 pairs of legs, ibidem, 17-XI-2012; 6 juveniles with 8-9 pairs of legs, ibidem, 12-XII-2012; 1 juvenile with 8 pairs of legs, ibidem, 23-I-2013; 2 juveniles with 8 or 10 pairs of legs, ibidem, 27-III-2013; 1 juvenile with 10 pairs of legs, ibidem, 24-IV-2013, coll. Y. Bu et al.; 12 juveniles with 7-10 pairs of legs, Jiangsu, Wuxi, Daji Mountain, 9-X-2017, coll. Y. Bu.

Description.

Adult body 2.2 mm long in average (1.7-3.1 mm, n = 40), holotype 2.1 mm (Fig. 4A ).

Head length 200-290 μm, width 200-350 μm, with widest part somewhat behind the middle on a level with the points of articulation of mandibles (Fig. 4F ). Central rod distinct, divided into two parts by a node-like interruption in the middle. Anterior branches normal, median branches vestigial. Head dorsally covered with setae of different length, longest setae (25-38 μm) located most anteriorly, at least 3.0 times as long as central shortest ones (8-11 μm). Cuticle on anterolateral part of head with fine coarse granules.

Tömösváry organ globular (Fig. 4F ), diameter 13-25 μm, 0.4-0.6 of greatest diameter of third antennomere (34-45 μm), opening round with length about half of greatest diameter of the organ, inner margins of openings covered with uniform vertical striae.

Mouthparts. Mandible with two fused lamellae and 11 teeth in total (Fig. 6A ). First maxilla has two lobes, inner lobe with four hooked teeth, outer lobe with teethed apex, palp straight, conical, pointed (Fig. 6B ). Anterior part of second maxilla with numerous small protuberances which carry one seta each, distal setae thicker and spiniform; posterior part with sparse setae (Fig. 4G ). Cuticle of maxilla and labium covered with dense pubescence (Fig. 4G ).

Antennae with 15-20 antennomeres, length 500-720 μm (550 μm in holotype), about one-quarter of body length. First antennomere shorter than second one, greatest diameter 1.2-1.7 times as wide as long (34-43 μm, 20-35 μm), with five to seven setae in one whorl, longest seta (20-21 μm) inserted at inner side and distinctly longer than outer ones (11-12 μm). Second antennomere wider (29-44 μm) than long (23-35 μm), with 6-10 setae evenly inserted around the antennal wall with interior setae (20-22 μm) slightly longer than exterior ones (13-15 μm). Chaetotaxy of third antennomere similar to preceding ones. Setae on proximal antennomeres longer and on distal antennomeres shorter. Proximal antennomeres with only primary whorl of setae (Fig. 4B ). Secondary whorl appearing ventrally on antennomeres 6-12 (Fig. 4E ). Three kinds of sensory organs on antenna: rudimentary spined sensory organs on dorsal side of most antennomeres except first antennomere (Figs 4D , 6D ); cavity-shaped organs on antennomeres 3-6 next to apical one, occasionally on apical antennomere (Figs 4D , 6D ); bladder-shaped organs on antennomeres 6-11 next to apical one increasing in number on subdistal antennomeres to a maximum of 16 (Figs 4C, E , 6D ). Apical antennomere subspherical, somewhat longer than wide (length 26-38 μm, width 25-28 μm), with 12-18 setae on distal half; two to five spined sensory organs consisting of three or four curved spines around a central pillar in depressions in distal surface (Figs 4D, E , 6C ). All antennomeres covered with short pubescence. Chaetotaxy and sensory organs of antennae are given in Table 4 .

Trunk with 17 dorsal tergites. Tergites 2-13, and 15 each with one pair of triangular processes. Length from base to tip of processes somewhat shorter than or the same as its basal width; basal distance between processes of tergites 4-13, and 15 longer than their length from base to tip (Table 5 ). All processes with round swollen ends (Figs 5B-E, G ). Anterolateral setae of tergites 2, 3, 4, 6, 7, 9 and 10 distinctly longer than other lateromarginal setae, approach length of process of same tergite (Fig. 5B-D ), that of tergites 5, 8, 11, 13 and 15 subequal or slightly shorter than longest ones of other lateromarginal (Fig. 5E, G ). Processes with one to three inserted setae. All tergites pubescent (Fig. 5B-G ).

Tergite. Tergite 1 reduced, with eight or nine unequal length setae in two groups (4+4 or 4+5) (Fig. 5A ). Tergite 2 complete, with two broad posterior processes, five to seven lateromarginal setae, one to three inserted setae, two or three central setae, with anterolateral setae 0.8-1.2 times as long as length of process, processes 0.8-1.0 time as long as broad, basal distance between processes 0.3-0.9 time as long as their length (Fig. 5B ). Tergite 3 complete, broader and longer than preceding one with ratios of 0.7-1.3, 0.7-1, and 0.5-1.1 respectively, 7-10 lateromarginal setae (Fig. 5C ). Tergite 4 broader than tergite 3, with ratios 1-1.7, 0.8-0.6, and 1-2.6 respectively, six to eight lateromarginal setae (Fig. 5D ). Chaetotaxy of tergites 5-7, 8-10, and 11-13 similar as tergites 2-4 (Fig. 5E ). Pattern of alternating tergite lengths of two short-tergites followed by a long-tergite only disrupted at the caudal end (Table 5 ). Tergites 14 and 16 without processes and with 12-26 and 9-16 setae respectively (Fig. 5F ). Tergite 17 with 18-27 setae. Chaetotaxy and measurements of tergites are given in Tables 5 and 6 .

Legs. First pair of legs reduced to two small, hairy cupules, each with at least one long setae (4-10 μm) (Fig. 4H ). Leg 12 about same length of head (Fig. 6F ), trochanter 1.2-1.8 times as long as wide (50-90 μm, 36-60 μm), with five to eight subequal setae; femur almost as long as wide (31-53 μm, 30-46 μm), with five or six setae and the dorsally protruding longest setae (20-27 μm) about 0.4-0.7 time of greatest diameter of podomere, laterally with cuticular thickenings in pattern of large scales; tibia nearly 1.3-1.9 times longer than wide (40-65 μm, 23-41 μm), with four to six dorsal setae: three straight and protruding, others slightly curved and depressed, longest seta 0.7-0.9 of greatest diameter of tibia; ventral setae distinctly shorter than dorsal ones; tarsus subcylindrical, about 3.1-4.2 times as long as wide (50-89 μm, 15-22 μm) with six dorsal setae: four straight and protruding, two curved and depressed; longest setae (16-25 μm) about same length or a little longer than greatest width of podomere; one or two ventral setae close to claw distinctly shorter than dorsal ones. Claws curved, anterior one somewhat longer and broader than posterior one, the latter more curved than the former. All legs covered with dense pubescences except areas with cuticular thickenings.

Coxal sacs present at bases of legs 3-9, fully developed, each with four or five setae on surface (Fig. 4J, K ). Relevant area of leg 2, 11, and 12 replaced by 1-3, 1-2, and 1-2 setae respectively (Fig. 4I ).

Styli present at base of legs 3-12, subconical (length 6-10 μm, width 3-6 μm), basal part with dense straight hairs; distal quarter hairless and blunt (3-5 μm) (Figs 4J, K , 6G ).

Sense calicles with smooth margin to pit. Sensory seta inserted in cup center, extremely long (120-180 μm).

Cerci about 0.4-0.8 of head length and leg 12, 2.4-3.3 times as long as its greatest width (115-178 μm, 37-63 μm), moderately covered with subequal length setae (Figs 5H , 6E ). Two types of setae inserted on cercus: slightly curved and depressed ones and three or four long and erect outer ones. Longest outer seta (23-32 μm) 0.5-0.7 of greatest width of cerci, terminal area (20-29 μm) short, circled by 7-10 layers of curved ridges. Terminal setae (25-30 μm) 1.0-1.4 times as long as terminal area.

Etymology.

The species name " communa " is derived from “common” which refer to the common morphology and wide distribution of the species.

Distribution.

China (Jiangsu, Shanghai, Zhejiang).

Remarks.

Symphylella communa sp. nov. is most similar to S. asiatica Scheller, 1971 from India and Sri Lanka and S. macropora Jin & Bu, 2019 from Tibet in the shape of the central rod, tergites, processes, anterolateral setae, and leg 12. It differs from S. asiatica and S. macropora in the size of the opening of the Tömösváry organ (moderate in S. communa sp. nov. vs very small in S. asiatica , extremely large in S. macropora ) and chaetotaxy of the first tergite (4+4 in S. communa sp. nov. and S. macropora vs 3+3 setae in S. asiatica ). It is also affiliated to S. neotropica (Hansen, 1903) from Brazil in the shape of tergites and processes, but can be easily distinguished by the central rod (both the anterior and posterior parts are in the same width in S. communa sp. nov. vs the anterior part is distinctly narrow than the posterior part in S. neotropica ).

Figures

Figure 4. Symphylella communa sp. nov. A habitus B left 2 nd- 5 th antennomeres, dorsal view C distal five antennomeres, dorsal view D distal five antennomeres, show lateral organs E distal five antennomeres, ventral view F head, dorsal view G head, ventral view H first pair of legs (arrows indicate the reduced legs) I coxa of leg 2 J coxa of leg 3 (arrows indicate styli) K coxa of leg 4 and male genital plate (arrows indicate styli). Scale bars: 100 μm (A); 20 μm (B-K).

Figure 5. Symphylella communa sp. nov. A posterior of head and 1 st tergite B 2 nd tergite (als-anterolateral seta, as-apical seta, cs-central seta, is-inserted seta, ibs-inner basal seta, lms-lateromarginal seta) C 3 rd tergite D 4 th tergite, right side E 5 th tergite F 14 th tergite G 15 th tergite H right cercus, dorsal view. Scale bars: 20 μm.

Figure 6. Symphylella communa sp. nov. A mandible B first maxilla C left apical antennomere, dorsal view D left 13 th antennomere, dorsal view E left cercus, dorsal view F 12 th leg G stylus on base of 3 rd leg, right side. Scale bars: 20 μm (A-F); 5 μm (G).