Symphylella zhongi 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 : 106-113

Symphylella zhongi Jin & Bu sp. n. Figures 3, 4, Tables 4, 5, 6, 7

Diagnosis.

Symphylella zhongi sp. n. is characterized by a globular Tömösváry organ with small and roundish opening, processes on tergites mostly longer than their basal width, ovoid swollen ends of processes, and mushroom-shaped sensory organs present on apical antennal segments.

Material Examined.

Holotype, female (slide no. XZ-SY2015049) (SNHM), China, Tibet, Linzhi City, Bomi county, Songzong town, extracted from soil samples from broadleaf forest, alt. 3000 m, 29°76'N, 95°96'E, 7-XI-2015, coll. Y. Bu & G. Yang. Paratypes, 2 females (slides nos. XZ-SY2015047-XZ-SY2015048) (SNHM), same date as holotype. Other materials: 3 juvenile with 8 or 9 pairs of legs (slides nos. XZ-SY2015050-XZ-SY2015052) (SNHM), same date as holotype.

Description.

Adult body 2.48 mm long on average (2.22-2.93 mm, n = 3), holotype 2.93 mm (Fig. 3A).

Head length 250-262 μm, width 262-287 μm, with widest part somewhat behind the middle on a level with the points of articulation of mandibles. Central rod distinct in both anterior (65-70 μm) and posterior (75-90 μm) portions, with a middle knot. Anterior branches well developed, median branches vestigial. Dorsal side of head moderately covered with setae of different length, longest setae (27-35 μm) located most anterior on head, at least 3.0 times as long as central ones (8-11 μm). Cuticle at anterolateral part of head with rather coarse granulation. Tömösváry organ surrounded by fine granulation, other area with faint dense granulation (Fig. 3D).

Tömösváry organ globular, length19-24 μm, width 16-22 μm, about half of greatest diameter of 3rd antennal segments (40-42 μm), opening small and roundish (length 8 μm, width 3-6 μm) (Figs 3C, D).

Mouthparts. Mandible with two fused lamellae and 11 teeth in total (Fig. 4A). First maxilla has two lobes, inner lobe with four hook-shaped teeth, palp bud-like with one distal point close to outer lobe (Fig. 4B). Anterior part of second maxilla with many small protuberances which carry one seta each, distal setae more thick and hard; posterior part with sparse setae. Cuticle of maxilla and labium covered with pubescence.

Antennae with 18-23 segments (left antenna with 19, right antenna with 21 in holotype), length 513-663 μm (663 μm in holotype), about one fourth of body length. 1st segment cylindrical, greatest diameter somewhat wider than long (40-42 μm, 23-40 μm), with 1 or 2 microsetae and 6 or 7 mesosetae in one whorl, longest seta (20-22 μm) inserted at inner side and distinctly longer than outer ones (14-15 μm). 2nd segment wider (25-28 μm) than long (40 μm), with 7 or 8 setae evenly inserted around the antennal wall with interior setae (20-21 μm) slightly longer than exterior ones (14-15 μm). Chaetotaxy of 3rd segment similar to preceding ones. Setae on basal segments longer and on distal segments shorter. Basal antennae segments with only primary whorl of setae, in middle and subapical segments several setae in secondary whorl. Four kinds of sensory organs on antenna: rso on dorsal side of most segments (Figs 4C, E); co on 7 th– 19th segments; bo on 9-11 segments next to apical one increasing in number on subdistal segments to a maximum of 21 (Figs 3B, 4C); mo on distal 2 segments (Fig. 4C). Apical segment subspherical, somewhat longer than wide (width 24-27 μm, length 32-35 μm), with 15-18 setae on distal half; 3-5 spined sensory organs consisting of 3 or 4 curved spines around a central pillar in depressions in distal surface; 2 baculiform organs on apex of segment (Figs 4C, D). All segment covered with short pubescence. Chaetotaxy and sensory organs of antennae are given in Table 4.

Trunk with 17 dorsal 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. Length from base to tip of processes somewhat longer than its basal width except for the 4th, 7th, 10th and 13th tergites, where processes are broader than long; basal distance between processes of 4 th– 13th and 15th tergite longer than their length from base to tip (Table 5). Triangular processes with ovoid swollen ends (Fig. 3I). Anterolateral setae of 2nd, 3rd, 4th, 6th, 7th, 9th and10th tergite dis tinctly longer than other lateromarginal setae, that of 5th, 8th, 11th -13th and 15th subequal or slightly longer than other lateromarginal. One to two inserted setae. All tergites pubescent.

Tergites. 1st tergite reduced and build up of two short plates separated in the median axis of the body, with 8 short setae in a row. 2nd tergite complete, with two slender posterior processes, 6-8 lateromarginal setae, 1 or 2 inserted setae, 2 central setae, with anterolateral setae distinctly longer than other lateromarginal ones, processes approximately 1.1 times as long as broad, basal distance between processes approximately 0.8 times as long as their length (Fig. 3E). 3rd tergite complete, broader and longer than preceding one with ratios of 1.1 and 0.9 respectively, 8 or 9 lateromarginal setae (Fig. 3F). 4th tergite broader than 3rd tergite, with ratios approximately 0.8 and 1.5 respectively, 6 or 7 lateromarginal setae (Fig. 3H). Chaetotaxy of 5 th– 7th, 8 th– 10th, and 11 th– 13th tergites similar to 2 nd– 4th tergites. Pattern of alternating tergite lengths of two short tergites followed by a long tergite only disrupted at the caudal end (Table 5). Within short tergites (1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16) the length augments toward caudal. Same is generally true for long tergites (3, 6, 9, 12, 15, 17), but for the 15th tergite being shorter than the others, with likewise smaller processes. 14th and 16th tergite without processes with 13-18 and 10-15 marginal setae respectively (Fig. 3J). 17th tergite with 32-44 setae. Chaetotaxy and measurements of tergites are given in Tables 5 and 6.

Legs. 1st pair of legs reduced to two small hairy cupules, each with two long setae (Fig. 3G). Basal areas of legs 2-12 each with 5-7 setae. Leg 12 about 0.1 times the length of the body, about same length like head. Trochanter distinctly longer than wide (70-83 μm, 40-50 μm), with 7 or 8 subequal setae. Femur as long as wide (38-43 μm, 35 -40 μm), with 5 setae and one of them (22 μm) distinctly longer than others (12-18 μm); trochanter and femur pubescent dorsally, ventrally with cuticular thickenings in pattern of large scales. Tibia nearly 2 times longer than wide (50-60 μm, 27-30 μm), with 6 dorsal setae and longest one nearly the same length as greatest diameter of tibia (21-30 μm). Tarsus subcylindrical, about 3.5 times as long as wide (68-75 μm, 20 μm) with 5 dorsal setae: 3 straight and protruding, 2 curved and depressed; longest setae (20-22 μm) about same length of greatest width of podomere; 2 ventral setae inserted near claw distinctly shorter than dorsal ones. Claws curved, anterior one somewhat longer and broader than posterior one, the latter more curved than the former (Fig. 4G). All legs covered with dense pubescences except areas with cuticular thickenings.

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

Styli present at base of 3 rd– 12th pairs of legs, subconical (length 5-8 μm, width 3-4 μm), basal part with straight hairs; distal quarter hairless and blunt (3-4 μm) (Figs 3G, 4F).

Sense calicles with smooth margin to pit, about same length as outer diameter (28-30 μm, 26-30 μm). Sensory seta inserted in cup center, extremely long, length 170-180 μm, at least 5.5 times longer than other two lateral setae (20-24 μm, 13-20 μm respectively) inserted at edge of cup.

Cerci subuliform, about 0.7 of head length and leg 12, length at least three times as long as its greatest width (150-188 μm, 45-58 μm), moderately covered with subequal length and slightly curved setae, with longest (25-28 μm) at least half of greatest width of cerci, terminal area (24-28 μm) short, circled by 6-8 layers of curved ridges. Terminal setae length 25 μm (Fig. 4H).

Etymology.

We dedicate this new species in honor of the late Professor Zhong Yang (1964-2017) who was an eminent botanist from Fudan University, for his great contribution to the knowledge of flora and biodiversity of Tibet.

Distribution.

Known only from the type locality.

Remarks.

Symphylella zhongi sp. n. is most similar to S. multisetosa Scheller, 1971 in the shape of the Tömösváry organ, as well as the shape and chaetotaxy of the tergites 1-4, 1st leg, but it deviates distinctly in the shape of the ends of the processes (with ovoid swollen ends in S. zhongi sp. n. vs without ovoid swollen ends in S. multisetosa ), chaetotaxy of the cerci (most setae subequal length and slightly curved in S. zhongi sp. n. vs long, straight, erect setae on dorsal, ventral, and outer sides of cerci arranged in one or two rows in S. multisetosa ). It is also similar to S. simplex (Hansen, 1903) in the shape and chaetotaxy of first two tergites, sensory organs of antennal segments and 1st leg, but differs in the shape of 1stantennal segment (moderate in S. zhongi sp. n. vs very short in S. simplex ), chaetatoxy of 3rd tergite (8 or 9 lateromarginal setae in S. zhongi sp. n. vs 11 or 12 in S. simplex ) and 4th tergite (6 or 7 lateromarginal setae in S. zhongi sp. n. vs 8 in S. simplex ), chaetotaxy of cerci (8-10 longish setae protruding, others short and depressed in S. simplex ).

The new species is compared with similar species in Table 7.

The 43 species of the genus Symphylella can be distinguished by the following key, but six species ( Symphylella natala Hilton, 1938, Symphylella vaca Hilton, 1938, Symphylella elongata Scheller, 1952, Symphylella foucquei Jupeau, 1954, Symphylella maorica Adam & Burtel, 1956, and Symphylella sp. Rochaix, 1956), which have very brief original descriptions, are not included.