Symphylella macropora Jin & Bu

Jin, Ya-Li, Bu, Yun & Jiang, Yue, 2019, Two new species of the genus Symphylella (Symphyla, Scolopendrellidae) from Tibet, China, ZooKeys 845, pp. 99-117 : 101-105

Symphylella macropora Jin & Bu sp. n. Figures 1, 2, Tables 1, 2, 3

Diagnosis.

Symphylella macropora sp. n. is characterized by large, elongated oval openings of the Tömösváry organs, with their inner margins of these openings covered by minute irregular teeth, as well as by having rudimentary spined sensory organs on the dorsal side of most antennal segments, and cerci with numerous long and slightly curved setae.

Material examined.

Holotype, female (slide no. XZ-SY2015030) (SNHM), China, Tibet, Motuo county, Dexing town, extracted from soil samples from broadleaf forest, alt. 1100 m, 29°40'N, 95°26'E, 3-XI-2015, coll. Y. Bu & G. Yang. Paratypes, 6 females (slides nos. XZ-SY2015023-XZ-SY2015026, XZ-SY2015029, XZ-SY2015032) (SNHM), 3 males (slides nos. XZ-SY2015027, XZ-SY2015028, XZ-SY2015031) (SNHM), same date as holotype; 1 female (slide no. XZ-SY2015034) (SNHM), China, Tibet, Motuo county, Beibeng town, extracted from soil samples from broadleaf forest, alt. 1500 m, 29°30'N, 95°38'E, 5-XI-2015, coll. Y. Bu & G. Yang. Other materials (SNHM): 1 juvenile with 9 pairs of legs (slide no. XZ-SY2015033) (SNHM), China, Tibet, Motuo county, Beibeng town, extracted from soil samples from broadleaf forest, alt.1500 m, 29°30'N, 95°38'E, 5-XI-2015, coll. Y. Bu & G. Yang; 2 juveniles with 9-10 pairs of legs (slides nos. XZ-SY2015035-XZ-SY2015036) (SNHM), same date as holotype; 10 juveniles with 8-10 pairs of legs (slides nos. XZ-SY2015037-XZ-SY2015046) (SNHM), China, Tibet, Motuo county, Dexing town, Naerdong village, extracted from soil samples from broadleaf forest, alt. 1800 m, 29°30'N, 95°23'E, 4-XI-2015, coll. Y. Bu.

Description.

Adult body 1.90 mm long in average (1.55-2.71 mm, n=11), holotype 1.89 mm (Fig. 1A).

Head length 210-270 μm, width 225-300 μm, with widest part somewhat behind the middle on a level with the points of articulation of mandibles. Central rod distinct in both anterior (50-70 μm) and posterior (58-75 μm) portions, with a middle knot. Anterior branches well developed, median branches vestigial. Head dorsally moderately covered with setae of different length, longest setae (25-35 μm) located most anteriorly, at least 3.0 times as long as central ones (8-12 μm). Cuticle at anterolateral part of head with rather coarse granulation. Tömösváry organ surrounded by fine granulation, other areas with fine dense granulation (Fig. 1D).

Tömösváry organ oval, length 19-32 μm, width 10-22 μm, at least half of greatest diameter of 3rd antennal segment (35-50 μm), openings large and elongated oval (length 13-26 μm, width 5-10 μm), with their inner margins covered by minute irregular teeth (Figs 1C, 1D).

Mouthparts Mandible with two fused lamellae and 11 teeth in total (Fig. 2A). First maxilla with two lobes, inner lobe with four hook-shaped teeth, palp bud-like with 1 distal point close to outer lobe (Fig. 2B). Anterior part of second maxilla with many small protuberances which carry one seta each, distal setae thickened; posterior part with sparse setae. Cuticle of maxilla and labium covered with pubescence.

Antennae with 16-23 segments (18 in holotype), length 570-680 μm (620 μm in holotype), about 0.3 of body length. 1st segment cylindrical, much shorter than follow ing ones, greatest diameter wider than long (37-45 μm, 13-33 μm), with 2-3 microsetae and 6-9 long mesosetae in one whorl, longest seta (20-24 μm) inserted at inner side and distinctly longer than outer ones (15-18 μm). 2nd segment wider (35-44 μm) than long (28-35 μm), with eight or nine setae evenly inserted around antennal wall, interior setae (23-26 μm) slightly longer than exterior ones (16-19 μm). Chaetotaxy of 3rd segment like preceding ones. Setae on basal segments slender and on distal segments shorter. Basal segments of antennae with only primary whorl of setae, in middle and subapical segments with several minute setae in secondary whorl. Three kinds of sensory organs on most antenna segments: rso on dorsal side of most segments (Figs 2C, 2E); co on dorsal side of 3 rd– 21th segments; bo on subapical 5-9 segments (Figs 1B, 2C, 2D). Apical segment subspherical, somewhat wider than long (width 28-32 μm, length 24-26 μm), with 13-15 setae on distal half and 2 baculiform organs on apex, 4-7 so consisting of 3-4 curved spines around a central pillar in depressions in distal surface (Figs 2C, 2D). All segments covered with short pubescence. Chaetotaxy and sensory organs of antennae are given in table 1.

Trunk with 17 tergites. Most tergites overlap, with intertergal zones present between adjacent tergites, except for borders between 14th and 15th, as well as 16th and 17th tergite. Tergites 2-13, and 15 each with one pair of triangular processes. Basal distance between processes of 4 th– 13thand 15th tergites longer than their length from base to tip, and the latter shorter than its basal wide (Table 2). Anterolateral setae of 2nd, 3rd, 4th, 6th, 7th, 9th and10th tergites distinctly longer than other lateromarginal setae, that of 5th, 8th, 11 th– 13th and 15th subequal or slightly longer than other lateromarginal setae. Triangular processes without ovoid swollen ends (Fig. 1G). One to three inserted setae (setae between inner basal seta and apical seta). All tergites pubescent.

Tergites 1st tergite reduced and build up of two short plates separated in the median axis of the body, with 6-9 short setae in a row. 2nd tergite complete, with two posterior processes, 5-8 lateromarginal setae, 1-2 inserted setae, 1-4 central setae, with anterolateral setae distinctly longer than other lateromarginal setae, processes approximately 0.9 times as long as broad, basal distance between processes approximately 0.7 times as long as their length. 3rd tergite entire, broader and longer than preceding one with ratios mentioned nearly the same as for the 2nd tergite, 6-10 lateromarginal setae (Fig. 1H). 4th tergite broader than 3rd tergite, with ratios approximately 0.7 and 1.4 respectively, 5-7 lateromarginal setae (Fig. 1I). Shape and chaetotaxy of 5 th– 7th, 8 th– 10th, and 11 th– 13th tergite similar as 2 nd– 4th tergite. 15th tergite shorter with smaller processes than remaining long tergites (3rd, 6th, 9th and 12th tergites). 14th and 16th tergites without processes, with 11-17 and 6-14 marginal setae respectively (Fig. 1J). 17th tergite with 20-31 setae. Chaetotaxy and measurements of tergites are given in Table 2, 3.

Legs 1st pair of legs reduced to two small hairy cupules, each with two long setae (Fig. 1E). Basal areas of legs 2-12 each with 4-6 setae (Fig. 1F). Leg 12 about 0.1 time as long as body, subequal length with head. Trochanter longer than wide (52-76 μm, 40-56 μm) with 6-8 subequal setae. Femur as long as wide (32-42 μm, 30-41 μm), with 4-6 setae and one of them (17-28 μm) distinctly longer than others (10-20 μm); pubescent dorsally, ventrally with cuticular thickenings in pattern of large scales. Tibia nearly 2 times longer than wide (40-60 μm, 23-30 μm), with 5-7 dorsal setae and the longest one slightly shorter than greatest diameter of tibia (19-28 μm).Tarsus subcylindrical, at least 3 times as long as wide (50-70 μm, 15-20 μm), with 6-9 setae: 3 straight and protruding, 2 curved and depressed; longest setae (20-27 μm) about same length of greatest width of podomere, and 2 ventral setae inserted near claw distinctly shorter than dorsal ones. Claws rather curved, anterior one distinctly longer and broader than posterior one, the latter more curved than the former (Fig. 2F). All legs covered with dense pubescence except areas with cuticular thickenings.

Coxal sacs present at bases of 3 rd– 9th pairs of legs, fully developed, each with 4 setae on its surface (Fig. 1F).

Styli present at base of 3 rd– 12th pairs of legs, subconical (length 6-9 μm, width 4-6 μm), basal part with straight hairs; distal one fourth hairless and blunt (3-6 μm) (Figs 1F, 2G).

Sense calicles with smooth margin to pit, length about the same as outer diameter (18-39 μm, 20-35 μm). Sensory seta inserted in cup center, extremely long, length 130-165 μm, at least 5.5 times longer than other two lateral setae (20-35 μm, 14-22 μm respectively) that inserted at the edge of cup.

Cerci subuliform, short, about 0.6 of head length and leg 12, length at least three times as long as its greatest width (126-172 μm, 40-53 μm), moderately covered with subequal length and slightly curved setae, with longest (20-40 μm) at least half of the greatest width of the cerci, terminal area (23-32 μm) short, circled by 6-8 layers of curved ridges. Terminal setae length 18-28 μm (Fig. 2H).

Etymology.

The species name macropora is referring to the large opening of the Tömösváry organ.

Distribution.

Known only from the type locality.

Remarks.

Symphylella macropora sp. n. is most similar to S. javanensis Scheller, 1988 from Java in the shape of tergites and processes, leg 12 and sensory organs on antennae. However, it can be readily distinguished from the latter by the shape of Tömösváry organ (oval, openings large and elongated with inner margins covered by minute irregular teeth vs subspherical, diameter of opening about half of the organ in S. javanensis ), central rod (both anterior and posterior portions distinct in S. macropora sp. n. vs anterior half and anterior branches very thin with traces in S. javanensis ), and the stylus (with blunt apex in S. macropora sp. n. vs with truncate apex in S. javanensis ). It is also closely related to S. asiatica Scheller, 1971 from Indiaand Sri Lanka in the shape and chaetotaxy of tergites 1-3, leg 12 and the sensory organs on antenna, but easily distinguished by characters of Tömösváry organ (openings very small in S. asiatica ), and the cerci (most setae subequal length and slightly curved in S. macropora sp. n. vs long and erect setae on dorsal, ventral and outer sides arranged in one or two rows in S. asiatica ).