Zephronia macula Srisonchai & Wesener, 2024

Srisonchai, Ruttapon, Likhitrakarn, Natdanai, Sutcharit, Chirasak & Wesener, Thomas, 2024, Integrative taxonomy reveals two new giant pill-millipedes of the genus Zephronia Gray, 1832 from eastern Thailand (Diplopoda, Sphaerotheriida, Zephroniidae), ZooKeys 1212, pp. 29-64 : 29-64

Zephronia macula Srisonchai & Wesener sp. nov.

Figs 8 , 9 , 10 , 11 , 12 , 13 , 14 E – H , 15

Type specimen.

Holotype • ♂ ( CUMZ - MYR 0015 ); Thailand, Chantaburi Province, Kaeng Hang Maeo District, near Khao Wong Kot Cave, Thamma Sooksawang Temple ; 12 ° 53 ' 51.7 " N, 101 ° 48 ' 59.7 " E; ca. 60 m a. s. l.; 14 June 2023; leg. R. Srisonchai and KKUMZ students . Paratypes. • 53 ♂, 74 ♀ ( CUMZ - MYR 0016 ), same data as holotype ; • 2 ♂, 2 ♀ ( NHMD 1184696 ), same data as holotype ; • 2 ♂, 2 ♀ ( NHMW 10437 ), same data as holotype ; • 2 ♂, 2 ♀ ( ZFMK - MYR 13660 ), same data as holotype .

Additional material.

• 29 juveniles ( CUMZ); Thailand, Chantaburi Province, Kaeng Hang Maeo District, near Khao Wong Kot Cave, Thamma Sooksawang Temple ; 12 ° 53 ' 51.7 " N, 101 ° 48 ' 59.7 " E; ca. 60 m a. s. l.; 14 June 2023; leg. R. Srisonchai and KKUMZ students ; • 26 ♂, 31 ♀ ( CUMZ); Thailand, Chantaburi Province, Tha Mai District, Wat Khao Sukim (Khao Sukim Temple); 12 ° 45 ' 47 " N, 102 ° 01 ' 56 " E; ca. 53 m a. s. l.; 14 June 2023; leg. R. Srisonchai and KKUMZ students ; • 18 ♂, 26 ♀ ( CUMZ); Thailand, Chantaburi Province, Khlung District, Thaeo Klong Khlung Monastery ; 12 ° 28 ' 53.3 " N, 102 ° 13 ' 06.3 " E; ca. 74 m a. s. l.; 14 June 2023; leg. R. Srisonchai and KKUMZ students ; • 26 ♂, 65 ♀; 47 juveniles ( CUMZ); Thailand, Chantaburi Province, Makham District, Wat Khao Banchob , 12 ° 51 ' 09.0 " N, 102 ° 12 ' 15.0 " E; ca. 110 m a. s. l.; 13 June 2023; leg. R. Srisonchai and KKUMZ students • 33 ♂, 43 ♀ ( CUMZ); Thailand, Chonburi Province, Bo Thong District, Wat Khao Yai Aran Khiri ; 13 ° 14 ' 54.7 " N, 101 ° 37 ' 29.6 " E; ca. 160 m a. s. l.; 15 June 2023; leg. R. Srisonchai and KKUMZ students ; • 66 ♂, 25 ♀ ( CUMZ); Thailand, Rayong Province, Makham District, Wat Pa Theprangsi (= Wat Khao Hin Tang); 12 ° 42 ' 03.3 " N, 101 ° 32 ' 17.3 " E; ca. 80 m a. s. l.; 14 June 2023; leg. R. Srisonchai and KKUMZ students ; • 5 ♂, 7 juveniles ( CUMZ); Thailand, Sa Kaeo Province, Khlong Hat District, Phet Pho Thong Cave ; 13 ° 24 ' 53.5 " N, 102 ° 19 ' 35.1 " E; ca. 245 m a. s. l.; 12 June 2023; leg. R. Srisonchai and KKUMZ students ; • 1 ♂, 2 ♀ ( CUMZ); Thailand, Sra Kaeo Province, Mueang Sra Kaeo District, Wat Tham Khao Maka ; 13 ° 47 ' 11.9 " N, 101 ° 56 ' 51.8 " E; ca. 70 m a. s. l.; August 2014; leg. ASRU members

Diagnosis.

The position of the organ of Tömösváry in this small Zephronia with an axe-shaped antennomere 6 identifies Z. macula sp. nov. as a member of the Zephronia s. s. species-group ( Semenyuk et al. 2018). Z. macula sp. nov. differs from all other known species of the group except for the syntopic Z. chantaburiensis sp. nov., in the presence of only a single apical spine on the tarsi of legs 4–21 (at least 2 or 3 in the other Zephronia ). Z. macula sp. nov. differs from Z. chantaburiensis sp. nov. by having a combination of distinct characters, viz. tergite with dark or greenish dark spots, femur of walking legs less strongly widened, slightly longer than wide (wider than long in Z. chantaburiensis sp. nov.), bristles of midbody endotergum reaching to posterior margin, operculum of female vulva not protruding and round, and immovable finger (process) of telopoditomere 2 of the anterior telopod more curved and much longer. Genetically distant from others by a p-distance of the COI barcoding fragment of 17.93–25.13 %.

Description.

Measurements: Male holotype. Body length 18 mm. Width, of thoracic shield 8 mm, of tergite 7 = 9 mm (= broadest). Height of tergite 7 = 6 mm (= highest). Males: body length = 18–20 mm. Width, of thoracic shield = 8–9 mm, of tergite 7 = 8–10 mm. Height of tergite 7 = 6–7 mm. Females: body length = 18–20 mm. Width, of thoracic shield = 8–9 mm, of tergite 7 = 9–10 mm. Height of tergite 7 = 6–8 mm (= highest).

Colouration (Fig. 8 A – G ): Specimen in life with body of brown / greenish brown / reddish brown colour, tergite with dark or greenish dark spots. Head, antenna, and collum dark brown. Thoracic shield, tergites and anal shield brown. Colour in alcohol after one year faded to brown.

Head (Fig. 9 A, B ): Trapeziform, densely setose; each seta located inside small pit. With 55–65 ommatidia (ocelli) in males and 61–70 in females. At rim of antennal groove with aberrant ommatidium. Organ of Tömösváry located near base of antenna, clearly separated from eye field. No sclerotized crest / ridge between antennal socket and eye field.

Antennae (Figs 8 C, D , 9 A, C – E ): Short and stout, covered by long and dense setae; last antennomere reaching back to leg pair 2 or 3 when stretched ventrally. Lengths of antennomeres: 1 = 2 = 3 = 4 <5 << 6. Antennomere 6 strongly flattened apically, axe-shaped; apically with sensilla basiconica. Apical disc slightly concave, with 48–57 apical cones (male) or 36–43 (female).

Epipharynx (Fig. 9 J ): With a large central tooth (ct); inner tooth conspicuous and swollen; laterally with group of long external teeth (et); inner area with a single row of fringed spines (rsp) on each side.

Gnathochilarium (Fig. 9 F – I ): As in Z. chantaburiensis sp. nov. Lamellae linguales (ll) oval, apically concave, with long setae. Central pads (Cp) modified, with numerous “ pillows ” of sensory cones (sc) (Fig. 9 H ); two different types of sensory cones (one with a pillow and another without a pillow). Stipites (st) large and stout, densely setose. Mentum (me) large and broad, fused, with long setae. Lateral palpi inconspicuous. Inner palpi (ip) with sensory cones (sc) arranged in single field (Fig. 9 G ).

Mandibles (gnathal lobe) (Fig. 9 K ): With undivided external tooth (Et) and with prominent 3 - combed inner tooth (3 it). With 5–6 pectinate lamellae (pl). Inner area (Ia) with group of long and tiny teeth, spine-like. Molar plate (mp) flat, velvet-like; lacking a membranous fringe. Condylus (co) conspicuous, apically with 2 distinct ridges.

Tegument (Figs 8 A – G , 10 ): Dull; collum, thoracic shield, tergite and anal shield with tiny golden setae; each seta located in small pit. Anterior margins of midbody tergite and of anal shield with lower number of setae than posterior margins. Posterior rim on dorsal and ventral side of anal shield with a few small setae.

Collum (Figs 8 C, D , 11 A ): Sub-semicircular; tip of lateral margin obtuse, covered with fine setae.

Thoracic shield (Fig. 10 B ): With a shallow, large, wide groove separated by a large and long ridge. Slope towards groove without keels. Groove smooth, without setae; on a ridge with a few setae.

Midbody tergite (Fig. 10 D – G ): With a row of oval impressions; anterior margin with tiny tubercles. Inner area with a crenate barrier; a wide and shallow groove. Tips of midbody paratergites projecting ventro-posteriad.

Anal shield (Fig. 10 H – M ): In female large and well-rounded, in male slenderer. With a row of oval impressions, edge of anterior margin with numerous tiny tubercles (sometimes arranged into rows). Inner area with a row of oval impressions, forming a crenate barrier; with a wide and shallow groove.

Endotergum of thoracic shield and midbody tergite (Fig. 14 E – H ): Thoracic shield similar to midbody tergites. Overall surface smooth. Posterior margin (pm) flat, not modified. Outer area (os) without setae. Bristles arranged in one row; tip of longest bristles reaching to posterior margin (Fig. 14 G, H showing short bristles). Middle area (ma) with a single row of conspicuous, oval cuticular impressions; distance between impressions twice as long as individual diameter. Inner area (ia) without tubercles or setae.

Pleurite (laterotergite) (Fig. 11 B ): Densely setose. First pleurite boomerang-shaped; apical margin attenuated; strongly projecting into sharp tip. Pleurite 2 projecting into an obtuse tip. Remaining pleurites flat and wide, lamella-like, apical margin extended.

Subanal plate of female (Fig. 11 C ): Sparsely setose. Large and broad (sometimes quite narrow), semicircular; apical margin slightly concave (rarely truncate / obtuse).

Stigmatic plates (Fig. 11 D, E ): First stigmatic plate large, slender; apex well-rounded, slightly curved towards basal part of prefemur. Second stigmatic plates in both male (Fig. 11 F ) and female (Fig. 11 J ) only very weakly curved towards coxa.

Legs (Fig. 11 D – L ): All podomeres with long setae. Coxa (cx) large, as long as length of prefemur; coxal process absent in first and second legs; legs 3–21 marginally with dentate process (tooth), conspicuous, broad. Prefemur (pre) stout; apico-mesally with weak projection; mesal margin with conspicuous and small spines. Femur (fe) short and stout, as long as length of prefemur; with a long ridge in all leg-pairs; apico-mesally with strong spines, forming a dentate margin. Postfemur (po) and tibia (ti) quite short. Tarsus (ta) of midbody legs quite short; as long as length of femur + postfemur; first two leg-pairs without an apical spine; leg-pair 1 with 1 ventral spine; leg-pair 2 with 3 ventral spines; leg-pair 3 with 4–6 ventral spines and 1 apical spine; leg pairs 4 with 6–8 ventral spines and 1 apical spine; leg pairs 5–21 with 7–9 ventral spines and 1 apical spine. In leg 9, length of femur equal to width, tarsus 4 × longer than wide. Claw normal, at base with a notch, conspicuous.

Male sexual characters (Fig. 11 F ): Gonopore large, with long setae; with divided sclerotized plates, triangular.

Anterior telopods (Fig. 12 A, B, E – G ): First telopoditomere stout, rectangular. Telopoditomere 2 large. Immovable finger (process of telopoditomere 2) quite long; as long as telopoditomere 3; clearly seen in posterior and anterior views; strongly curved; tip obtuse, directed anteriad and close to basal part of telopoditomere 4; with a large membranous lobe; with sclerotized spots located at inner margin. Telopoditomere 3 longer than telopoditomere 4; clearly demarcated from telopoditomere 4 by conspicuous suture; apically with crenulated teeth (cr-t). Tepoloditomere 4 apically with a few setae located in the side pits.

Posterior telopods (Figs 12 A – D, H – J ; 13 ): With 4 telopoditomeres. First telopoditomere rectangular, stout; slightly longer than wide. Telopoditomere 2 large and stout. Immovable finger (process of telopoditomere 2) long and slender, 3 × longer than wide; equal in length to movable finger (= combination of telopoditomeres 3 + 4); attenuate near tip; tip obtuse, in-situ curving anteriad; inner margin with conspicuous sclerotized spots (scl-s) in a blackish ledge and two large membranous lobes (ml). Telopoditomere 3 long, 2.5 × longer than wide, inner margin with a long membranous ledge and basally with a single spine. Telopoditomere 4 quite short; 3.5 × shorter than telopoditomere 3; slightly tapering toward apex; with two spines located on membranous ledge at inner margin; with 9 or 10 large crenulated teeth (cr-t) posteriorly. Telopoditomeres 1 mostly glabrous, telopoditomere 2 in posterior view mostly glabrous, in anterior view covered by setae. Telopoditomeres 3 and 4 in posterior view glabrous; at basal part of telopoditomere 3 in anterior view sparsely setose. Inner horns with sharp-edged tips, slightly curved caudad.

Female sexual characters (Fig. 11 J, K ): Vulva large and stout, sparsely setose; covering almost 1 / 3 of coxa; located at mesal margin; mesally extended to base of prefemur. Operculum (op) broad and well-rounded; swollen dorsoventrally, mesal margin not protruding; tip of operculum truncate. Bursa (bu) large, completely demarcated from operculum by a triangular groove.

Remarks.

Intrapopulational variation was found in which most specimens have a brown / reddish brown (majority) colour, while the others are greenish brown (minority). In addition, the posterior margin of subanal scale is in most specimens wide, whereas some specimens possess a quite narrow margin.

Distribution and habitat.

This species is widely distributed across eastern Thailand (> 150 km). Most specimens were collected from locations with granitic rock habitats, while a few localities were in forested limestone habitats (Fig. 8 H, I ). All individuals were encountered during the day under rotten logs and in leaf litters.

Etymology.

The name is a noun referring to the pattern of spots on the body.

Figures

Figure 8. Photograph of live specimens of Zephronia macula sp. nov. and habitats A – G paratypes (CUMZ - MYR 00016) H habitat at Thaeo Khlong Khlung monastery (granitic rocks) I habitat at Phet Pho Thong cave (limestone). Scale bars: 0.5 mm.

Figure 9. Zephronia macula sp. nov., ♂ paratype (CUMZ - MYR 0016) — SEM A head, collum and antenna, dorsal view B ommatidia, inset: organ of Tömösváry C antenna, anterior view D antennal disc, anterior view E apical cones, lateral view F, I gnathochilarium, posterior and ventral views, respectively G sensory cones on central pad, ventral view H sensory cones on inner palpi, black and white arrows point to different types of cones, ventral view J epipharynx, ventral view, K mandible, mesal view. Abbreviations: 3 it = 3 - combed inner tooth, co = condylus, Cp = central pad, ct = central tooth, et = external tooth, Et = external tooth, Ia = inner area, il = incisura lateralis, ip = inner palpi, ll = lamellae linguales, me = mentum, mp = molar plate, pl = pectinate lamellae, rsp = row of spines, sc = sensory cone, st = stipites. Scale bars in millimetres.

Figure 10. Zephronia macula sp. nov., ♂ paratype (CUMZ - MYR 0016) — SEM A surface of collum B, C thoracic shield, all in dorsal views (anterior margin and surface, respectively) D – G midbody tergite, all in dorsal views (overview, anterior margin, surface, and posterior margin, respectively) H – J anal shield, all in dorsal views (overview, anterior margin and cuticular impressions, respectively) K – M anal shield, underside, all in ventral views (surface, posterior margin, and overview, respectively). Scale bars in millimetres.

Figure 11. Zephronia macula sp. nov. — SEM A – G, L ♂ paratype (CUMZ - MYR 0016) J, K ♀ paratype (CUMZ - MYR 0015) A collum B seventh pleurite C subanal plate D legs 1 E stigmatic plate 1 F legs 2 with gonopores G leg 10 (arrow points to femoral ridge) H coxal process on leg 10 I small teeth on femur J leg 2 with vulvae K vulvae L tarsus 10. Abbreviation: bu = bursa, cx = coxa, fe = femur, op = operculum, po = postfemur, pre = prefemur, st-pl = stigmatic plate, ta = tarsus, ti = tibia. Scale bars in millimetres.

Figure 12. Zephronia macula sp. nov., ♂ paratype (CUMZ - MYR 0016) — SEM A – D overview of telopods (anterior view, lateral view with emphasis on anterior telopod, posterior view and ventral view, respectively) E – G anterior telopod (telopoditomeres 2–4, movable finger, and crenulated teeth, respectively) H – J posterior telopod (sclerotize spots on immovable finger, telopoditomeres 2–4 with emphasis on membranous lobe and crenulated teeth, respectively). Abbreviations: cr-t = crenulated teeth, ml = membranous lobe, scl-s = sclerotized spots. Scale bars in millimetres.

Figure 13. Zephronia chantaburiensis sp. nov., ♂ paratype (ZFMK - MYR 13660), drawings — left posterior telopod A anterior view B posterior view. Abbreviations: cr-t = crenulated teeth, imf = immovable finger, ml = membranous lobe. Scale bar: 0.5 millimetres.

Figure 14. Endoterga of thoracic shields and midbody tergites — SEM A – D Zephronia chantaburiensis sp. nov. (♂ paratype, CUMZ - MYR 0014) E – H Zephronia macula sp. nov. (♂ paratype, CUMZ - MYR 0016) A, B, E, F thoracic shields C, D, G, H midbody tergites. Abbreviations: cp = cuticular impression, ia = inner area, ma = middle area, oa = outer area, pm = posterior margin. Scale bars in millimetres.

Figure 15. Distribution and localities of Zephronia species in Thailand. Number inside the circle indicates species: 1 = Z. chantaburiensis sp. nov.; 2 = Z. chrysomallos; 3 = Z. enghoffi; 4 = Z. erawani; 5 = Z. golovatchi; 6 = Z. lannaensis; 7 = Z. macula sp. nov.; 8 = Z. panhai; 9 = Z. phrain; 10 = Z. siamensis; 11 = Z. viridisoma.