Zephronia chantaburiensis Srisonchai & Wesener 2024, sp. nov.
Creators: name: Srisonchai, Ruttapon
name: Likhitrakarn, Natdanai
name: Sutcharit, Chirasak
name: Wesener, Thomas
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Sphaerotheriida
Zephroniidae
Zephronia
Zephronia chantaburiensis

description: Zephronia chantaburiensis Srisonchai & Wesener sp. nov.
Figs 2, 3, 4, 5, 6, 7, 14 A – D, 15
Type specimens:
Holotype • ♂ (CUMZ - MYR 0013); 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. Paratypes. • 29 ♂, 16 ♀ (CUMZ - MYR 0014), same data as holotype; • 2 ♂, 1 ♀ (NHMD 1184695), same data as holotype; • 1 ♂, 1 ♀ (NHMW 10436), same data as holotype; • 1 ♂, 1 ♀ (ZFMK - MYR 13659), same data as holotype.
Additional material.
• 26 juveniles (CUMZ), same data as holotype.
Diagnosis.
The position of the organ of Tömösváry at the brim and not inside the antennal groove (Fig. 3 B) identifies this species as a member of the Zephronia s. s. species group (see Semenyuk et al. 2018), with which it also aligns genetically (Fig. 1). This small brown species (body length ca 20 mm) with short golden hair (Fig. 2 A – F) differs from all other Zephronia s. s. species, except for Z. macula sp. nov. found in direct sympatry, described below, in the presence of only a single apical spine on the tarsus of legs 4–21 (2 or 3 in the other species). Midbody endotergum with one row of marginal bristles with longest bristles reaching up to posterior margin, immovable finger (process) of telopoditomere 2 on anterior telopod relatively long and slender. Similar in these respects only to Z. macula sp. nov. but differs from the latter species by the tergite coloration lacking dark or greenish-dark colour spots, the operculum of the female being more slender, the femur of the walking legs being slightly wider than long (slightly longer than wide in Z. macula sp. nov.), and the female subanal plate having a strongly concave margin. Genetically distant from other species by 18.94–26.82 % p-distance in the COI barcoding fragment.
Description.
Measurements: Male holotype. Body length 20 mm. Width, of thoracic shield 9 mm, of tergite 7 = 10 mm (= broadest). Height of tergite 7 = 7 mm (= highest). Males: body length = 19–23 mm. Width, of thoracic shield = 8–9 mm, of tergite 7 = 9–10 mm. Height of tergite 7 = 6–8 mm. Females: body length = 19–22 mm. Width, of thoracic shield = 8–9 mm, of tergite 7 = 9–11 mm. Height of tergite 7 = 6–8 mm (= highest).
Colouration (Fig. 2 A – F): In life with body of brown colour. Head, collum, thoracic shield and tergites brown. Antenna, legs, and venter light brown. Anal shield dark brown (rarely brown), except anterior and posterior margins pale brown. Tergites dorsally with dark brown stripe, clearly seen when rolled up. Specimens in alcohol after one year changed to pale brown.
Head (Fig. 3 A, B): Trapeziform, densely setose; anterior part with setae longer than in posterior part; each seta located inside small pit. With 57–65 ommatidia (ocelli) in males and 60–65 in females. Aberrant ommatidium located at brim of antennal groove. Organ of Tömösváry situated near the base of antenna, separated from eye field. No sclerotized crest / ridge between antennal socket and eye field.
Antennae (Figs 2 B, C, 3 A, C – E): Short and stout, covered by long and dense setae; last antennomere reaching back to leg pair 2 or 3. Lengths of antennomeres: 1 = 2 = 3 = 4 <5 << 6. Antennomere 6 slightly flattened apically, axe-shaped; apically with sensilla basiconica. Apical disc flat; with 30–41 (male) or 25–35 (female) apical cones.
Epipharynx (Fig. 3 J): With a regular central tooth (ct); inner tooth conspicuous and flat; laterally with numerous long external teeth (et); inner area with a single row of fringed spines (rsp) on each side.
Gnathochilarium (Fig. 3 F – I): Structure as typical as for Sphaerotheriida. Lamellae linguales (ll) oval, slightly concave apically, with long setae. Central pads (Cp) modified, with numerous “ pillows ” of sensory cones (sc) (Fig. 3 H); two types of sensory cones (one with a pillow and another without a pillow). Stipites (st) large, densely setose; located laterally to lamellae linguales. Mentum (me) large, fused, with sparse and long setae. Lateral palpi inconspicuous. Inner palpi (ip) with sensory cones (sc) arranged in single field (Fig. 3 G).
Mandibles (gnathal lobe) (Fig. 3 K): With undivided external tooth (Et) and with conspicuous 3 - combed inner tooth (3 it). With 5–7 pectinate lamellae (pl). Inner area (Ia) with group of long and tiny teeth. Molar plate (mp) flat, velvet-like; lacking a membranous fringe. Condylus (co) conspicuous, apically with one distinct ridge.
Tegument (Figs 2 A – F, 4): Quite dull; collum, thoracic shield, tergite and anal shield densely covered by tiny golden setae; each seta located in a pit. Anterior margins of midbody tergite and of anal shield with lower number of setae than posterior margins. Posterior rim in dorsal and ventral side of anal shield with a few small setae.
Collum (Figs 2 B, 3 A): Subsemicircular; tip of lateral margin obtuse, densely setose.
Thoracic shield (Fig. 4 B): With shallow and large groove separated by a large and long ridge. Slope towards groove without keel. Groove and ridge smooth, without setae.
Midbody tergite (Fig. 4 D – G): With a row of oval impressions and numerous tiny tubercles at anterior edge. Inner area with crenate barrier, forming a wide and shallow groove. Tips of midbody paratergites projecting caudoventrad.
Anal shield (Fig. 4 H – M): Slightly sexually dimorphic, in female large and well-rounded, in male slightly slenderer. With a row of oval impressions and several tiny tubercles at anterior edge. Inner area with crenate barrier, forming a wide and shallow groove. Underside with a single, short, black locking carina; twice as long as those of tergites, as long as half of tarsus.
Endotergum of thoracic shield and midbody tergite (Fig. 14 A – D): Thoracic shield similar to midbody tergite. Posterior margin (pm) flat, regular. Outer area (os) without setae. Marginal bristles arranged in one row, tip of the longest bristles very slightly protruding above posterior margin. Middle area (ma) with a single row of conspicuous, circular cuticular impressions; distance between impressions twice as long as individual diameter. Inner area (ia) without tubercles or setae.
Pleurite (laterotergite) (Fig. 5 B): With short setae. First pleurite slender, boomerang-shaped; apical margin slightly attenuated; strongly projecting into a wide tip. Pleurite 2 wider than first one, projecting into obtuse tip. The remaining pleurites flat and wide, lamella-like, apical margin slightly extended.
Subanal plate of female (Fig. 5 C): Large and wide, semicircular; sparsely setose; apical margin strongly concave.
Stigmatic plates (Fig. 5 D, E): First stigmatic plate slender, apex well-rounded, slightly curving towards coxa (Fig. 5 E). Second stigmatic plate in both sexes without any curve (Fig. 5 F, J).
Legs (Fig. 5 D – L): All podomeres densely setose. Coxa (cx) large; coxal process absent in first and second legs; legs 3–21 marginally with large and dentate process. Prefemur (pre) short and stout; apico-mesally with a weak projection; mesal margin with small spines. Femur (fe) stout; with long ridge in all leg-pairs; apico-mesally massively enlarged with a strong projection carrying dentate margin (conspicuous teeth on margin). Postfemur (po) and tibia (ti) short. Tarsus (ta) of midbody legs quite long and slender; as long as length of prefemur + femur combined; 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 5 or 6 ventral spines and 1 apical spine; leg pairs 4 with 7 or 8 ventral spines and 1 apical spine; leg pairs 5–21 with 7–9 ventral spines and 1 apical spine. In leg 9, femur slightly wider than long (1.1 ×), tarsus 4 × longer than wide. Claw normal, with a small notch at base.
Male sexual characters (Fig. 5 F): Gonopore large, covered by long setae; with divided sclerotized plates, triangular.
Anterior telopods (Fig. 6 A, B, E – G): First telopoditomere rectangular. Telopoditomere 2 large, as long as telopoditomere 3. Immovable finger (process of telopoditomere 2) long and slender; almost as long as movable finger (= combination of telopoditomeres 3 + 4); clearly seen in posterior and anterior views; strongly curved; tip obtuse, directed anteriad; with a membranous lobe and sclerotized spots located at inner margin. Telopoditomere 3 as long as telopoditomere 4, clearly demarcated from telopoditomere 4 by conspicuous suture; apically with few crenulated teeth (cr-t). Tepoloditomere 4 apically with large and long setae.
Posterior telopods (Figs 6 A – D, H – J; 7): Consisting of 4 telopoditomeres. First telopoditomere rectangular, slightly longer than wide. Telopoditomere 2 large and stout. Immovable finger (process of telopoditomere 2) long and slender, 3 × longer than wide, with a characteristic swelling mesally; slightly longer than movable finger (= combination of telopoditomeres 3 + 4); attenuate near tip; tip obtuse; tip in situ curving anteriad; inner margin with few conspicuous sclerotized spots (scl-s) and two membranous lobes (ml). Telopoditomere 3 long, 2.5 × longer than wide, with a membranous ledge and single spine at excavate inner margin. Telopoditomere 4 relatively short; 4 × shorter than telopoditomere 3; 1.5 × longer than wide, slightly tapering toward apex; with two long spines located on membranous ledge; posteriorly with 9–12 crenulated teeth (cr-t). Telopoditomeres 1 and 2 in anterior view mostly covered by setae, in posterior view mostly glabrous. Telopoditomeres 3 and 4 glabrous, except small area at basal part of telopoditomere 3 with setae. Inner horns with sharp-edged tips, slightly curved caudad.
Female sexual characters (Fig. 5 J, K): Vulva large, slender, sparsely setose; covering almost 1 / 2 of coxa; located at mesal margin; extending mesally to base of prefemur. Operculum (op) round, mesal margin protruding into an oval-like lobe, tip of operculum obtuse. Bursa (bu) large, demarcated from operculum by a triangular groove.
Remarks.
Negligible colour variation is observed in the anal shield between different living specimens. Generally, they are dark brown in most specimens and pale brown in others. Females are typically of the same size as males.
Distribution and habitat.
Zephronia chantaburiensis sp. nov. is currently known only from the type locality in Chantaburi Province and is therefore here regarded as an endemic species. The new species was encountered during the day time in evergreen forest in granitic habitat (Fig. 2 H). They hide themselves beneath thick leaf litter and decayed wood logs (Fig. 2 G). Co-occurring and dominant millipedes are included, Z. macula sp. nov. and Desmoxytes euros Srisonchai et al., 2018.
Etymology.
The name is an adjective referring to the province (Chantaburi) where the type locality is located.
description: Published as part of 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), pp. 29-64 in ZooKeys 1212 on pages 29-64, DOI: 10.3897/zookeys.1212.126536