Hainanthereua albilineatasp. nov. by monotypy and present designation.

Antenna ca. 1.5 times as long as the body. First flagellum of antenna with 55–101 annulations (including node). Anterior projection of cephalic transverse sutures short, triangular, posterior part subparallel. Stomatotergites with a prominent white median longitudinal stripe; bristles (Stachelborsten) associated with elongate, conical, unpaired spines as long as bristles on TT4–7, and short paired spines on all tergites; the ratio of paired spines to unpaired spines associated with Stachelborsten on T6 is approximately 1:1 to 1:2, bristles (Stachelborsten) on borders with short paired spines along posterior margin. Elongate triangular spiculae, relatively sparse. Stomata elongate. Prefemur of legs 3–9 lacking a saw-like row of spines (sometimes legs 1–9). Legs 1–14 with pairs of tarsal papillae on consecutive tarsomeres, short-long alternation of tarsal papillae on legs 1–9, and uniform size of tarsal papillae on legs 10–14 (paired long papillae). Proarthron and metarthron of female gonopods subparallel-sided.

The name Hainanthereua (feminine) is a compound derived from ‘Hainan-’ (Hainan Province, China) and the common scutigerid suffix -thereua, meaning “the scutigerid genus of Hainan Province, China”.

Hainanthereuagen. nov. resembles Thereuonema in the cephalic sutures and the spines on the stomatotergites (all associated with a Stachelborste). Hainanthereua differs from this genus in color, form of spiculae, and stronger Stachelborsten. The dark pigmented band on the stomatotergites of Thereuonema is rather diffuse, while there is a distinct white longitudinal stripe in the middle of the stomatotergites of Hainanthereua. The spiculae of Hainanthereua are short triangular or more elongate, relatively sparse. In marked contrast, the spiculae of Thereuonema are dense, long, needle-like and variably parallel-sided (Verhoeff 1904, 1905; Würmli 1975a; Edgecombe and Giribet 2006: fig. 2f; Edgecombe 2011; Dyachkov 2026).

Hainanthereuagen. nov. resembles Thereuopoda, Thereuopodina and Pilbarascutigera Edgecombe and Barrow, 2007 in the shape of its spiculae (Edgecombe 2007), but those of Hainanthereua are relatively longer than in the other three genera. Thereuopoda possesses a unique kinked cephalic suture, while that of Hainanthereua, Thereuopodina and Pilbarascutigera is of the M-shaped type common in Scutigeridae (Edgecombe 2011). Compared to Pilbarascutigera with stoma-saddles weakly vaulted, the stoma-saddle of Hainanthereua is moderately vaulted, while that of Thereuopoda is strongly vaulted and is approached by that of Thereuopodina (Edgecombe and Barrow 2007). In addition, the stomatotergites bear spines associated with Tastborsten in Thereuopoda and Pilbarascutigera (anterior tergites bearing Stachelborsten and Tastborsten but lacking spines), while Hainanthereua and Thereuopodina bear Stachelborsten. Hainanthereua differs from Thereuopodina in having the margins of the proarthron and mesarthron of the female gonopods diverging in Thereuopodina v. subparallel-sided in Hainanthereua; and the prefemur of legs 2–4 of Thereuopodina lacking a saw-like row of spines whereas Hainanthereua lacks them on legs 3–9 (sometimes 1–9).

Hainanthereuagen. nov. resembles Allothereua and Parascutigera in the spines on the stomatotergites being associated with Stachelborsten and the margin of the proarthron and mesarthron of female gonopods being subparallel-sided. The spiculae of Allothereua and Parascutigera are, however, variably setiform (Edgecombe and Giribet 2006), rather than elongate triangular as in Hainanthereua, and they are considerably denser in the former two genera. The Stachelborsten on TT5–7 of Parascutigera are associated with paired spines, unpaired spines being wholly lacking (Verhoeff 1904, 1905; Edgecombe and Giribet 2006; Edgecombe 2011), but both types of bristles/spines are present on the stomatotergites of Allothereua and Hainanthereua.

Like SeychellonemaButler et al. 2010, Hainanthereuagen. nov. expresses a short-long alternation of tarsal papillae on successive tarsomeres. In Seychellonema, this feature is present on legs 1–7, while legs 8–14 bear paired short papillae of uniform size (Butler et al. 2010). However, in Hainanthereua, the alternation is observed on legs 1–9, and uniform size of tarsal papillae on legs 10–14 (paired long papillae). Würmli (1975b) interpreted such alternation in the holotype of Lassophora madagascariensis Verhoeff, 1905 as unreliable for generic diagnosis because the specimen is a praematurus, and mature specimens have uniform papillae. This morphology is, however, retained in mature specimens of Seychellonema and Hainanthereua. Accordingly, we include it in the generic diagnosis.

Holotype: CHINA • ♀; Mingfenggu Valley, Jianfengling, Ledong Li Autonomous County, Hainan Province, China (Fig. 2), 18.7426°N 108.8400°E, 990 m a.s.l., 22 June 2021, leg. Chao Jiang & Tianyun Chen (labelled as CMMI-20210622177). Paratypes: CHINA • 2♀♀ 5♂♂, same as holotype, 22–23 June 2021, leg. Chao Jiang & Tianyun Chen (CMMI-20210622104, CMMI-20210622174, CMMI-20210622176, CMMI-20210622179, CMMI-20210623126, CCMI-20210623127, CMMI-20210623128); CHINA • 2♀♀ 3♂♂, Mt. Diaoluoshan, Benhao Town, Lingshui Li Autonomous County, Hainan Province, China, 18.7272°N 109.8724°E, 900 m a.s.l., 24–25 June 2021, leg. Chao Jiang & Tianyun Chen (CMMI-20210624170, CMMI-20210624171, CMMI-20210625112, CMMI-20210625173, CMMI-20210625175).

As for genus.

Body length (from anterior edge of head capsule to tip of gonopods): 18–23 mm in adult. — Colour: Head capsule brown (Fig. 3A, B); antennal base ferruginous grading distally to pale yellow; stomatotergites with a prominent white median longitudinal stripe, black and brown on both sides, margins dark brown (Figs 2D, 2E, 3C, 3D, 8A–F); stoma saddle red (Fig. 2D, E); legs yellow with conspicuous black bands on prefemur, femur, and tibia (Fig. 2D, E, 3A); sternites pale yellow; female gonopods yellow (Fig. 8G) (based on living specimens). — Head capsule: Anterior projection of the cephalic transverse sutures short, triangular, posterior part parallel; transverse suture long; longitudinal median depression extends from the base of the antennae to between the two eyes (Figs 3A, 3B, 10A, 10C). Antenna ca. 1.5 times as long as body length. First flagellum of antenna with 55–101 annulations (including the first node). Annulations much wider than long (Figs 3A, 3B, 10A, 10C), with three or four whorls of flattened trichomes, a few beak-like sensilla, and a few setae (trichoid sensilla) associated with paired spines connected to the base form a single whorl encircling the distal end of the annulation. Tömösváry’s organ small (Fig. 3B), in typical position between eye and base of antenna (Fig. 2D, E). — Epipharynx: Arrangement typical for Scutigeridae (Koch and Edgecombe 2006: fig. 1) (Fig. 4). Lateral bar of labral trapezoid with narrow longitudinal groove along whole length of bar (Fig. 4A). Labral bristles differentiated into narrow outer band of short, pectinate bristles and wider inner band of longer simple bristles (Fig. 4A, C). Two clusters of sensilla along mid-line of labral trapezoid: more distal unpaired, transverse group of a few dozen bottle-shaped sensilla at termination of median ridge (Fig. 4B); the three proximal sensilla clusters of the labral part are composed of nipple-and bottle-shaped sensilla, median sensilla completely distal to lateral clusters (Fig. 4D). Chevron-shaped spine row of triangular and distally-curved denticles at the border (Fig. 4A, E, F) between labral and clypeal part of epipharynx; immediately proximal to the spine row is a rhomboid branched-spine field having transverse axis approximately 1.5 times the length of longitudinal axis, with a dense median field of pectinate spines (Fig. 4E). Broadly ovate cluster of bottle-shaped sensilla on medial part of clypeal triangle, a short distance behind dense field of branching spines (Fig. 4G). Lateral clusters of nipple-shaped sensilla positioned in a depression within the non-sclerotized area distal to the oblique bar and proximal to the edge extending from the submarginal armature to the transverse bar of the labral trapezoid. — Hypopharynx: Elongate, deeply projecting into preoral chamber (Fig. 5). Bars of lateral sclerotised fork with lateral bulges. Median excavation on proximal part of frontal and distal part of hypopharynx surface bordered laterally by pectinate bristles (Fig. 5A, D). Proximal cluster of sensilla (Fig. 5B, C) composed of a few sparse elements distributed in rows between mouth and a median elevation proximal to the median excavation. Area between the median excavation and the converging flattened bars of the proximal fork is sub-triangular with serrated spines at the proximal end of the carina (Fig. 5B, D). Inner margin of the tongue tip has strong irregular folds (Fig. 5E–G), on which nipple-shaped sensilla are distributed (Fig. 5E–G). — Mandible: Incisor region composed of three teeth, all with surface smooth and three cusps. Approximately 16 pectinate lamellae in gnathal lobe. Molar plate surrounded by a Haarpolster of approximately the same length. (Fig. 6A) — Second maxilla: Dorsal and ventral spine bristles on prefemur, four spine bristles on femur; two dorsal spine bristles on tibia (Fig. 6B). Ventral side of all podomeres and dorsal side of femur with rows of bristles. All spine bristles with similar surface details, spiniform scales, short proximally, becoming more elongate distally to confer a ridged or fluted surface to distal third of spine bristle. — Forcipular segment: Four spine bristles on anterior margin of coxa approximately equal in length to coxa. Spine comb of tarsus covering the entire inner side of the segment and composed of flattened setae mostly inserted by pairs in the bases and terminating in a rounded bulb. Ventrolateral side of trochanteroprefemur and femur with rows of spine bristles. Venom gland extending to distal part of tibia (Fig. 6C). — Stomatotergites: Stomatotergites with rugose surface (Fig. 7), posterior borders evenly rounded (Figs 2E, 3A, 3C, 3D, 7C, 7G, 8A–F, 10A, 10B). Stoma saddles moderately inflated; stomata elongate; with stomata 0.5–0.7 times the length of the stoma saddles (Fig. 7C, D). Stomatotergites bearing bristles (Stachelborsten) associated with elongate, conical, unpaired spines, as long as the bristles, or short paired spines (Figs 7A–E, 10F); spiculae short triangular or more elongate, emerging between the scutes, each separated by several polygonal scales that lack spiculae, relatively sparse (Figs 7, 10F); spinulae occur exclusively on T8 (Fig. 7G, H). Unpaired spines usually initially occur on T4 (on TT4–7), sparse, and always associated with a Stachelborste; 27–51 bristles associated with a spine on T6 (Figs 8D, 10D), uniformly distributed. Paired spines short; association with Stachelborste on TT1–8, 30–55 bristles associated with spines on T6 (Figs 8D, 10D). In adults, the ratio of paired spines to unpaired spines associated with Stachelborsten on T6 is approximately 1:1 to 1:2. Stomatotergite lateral margins and posterior margin with marginal bristles (Stachelborsten) with short, conical unpaired spines (Figs 7F, 10G). — Legs: Tarsus I and II tarsomeres as follow (range in tarsus I/tarsus II): leg 1, 11–16/25–31; leg 2, 10–11/27–30; leg 3, 10–11/25–30; leg 4, 7–9/24–30; leg 5, 7–9/24–30; leg 6, 7–9/24–27; leg 7, 7–8/19–29; leg 8, 6–7/22–27; leg 9, 6–8/24–28; leg 10, 6–7/28–29; leg 11, 6–8/29–30; leg 12, 6–8/26–32: leg 13, 8/31–34; leg 14, 7–9/29–32. Prefemoral spine-bristles in a 2/1 pattern on legs 1–14; femoral spine-bristles 1/2 on legs 1–14; tibial spine-bristles 1/1 on legs 1–11 and 1/2 on legs 12–14. Prefemur of legs 3–9 lacking a saw-like row of spines (sometimes legs 1–9). Pair of spine-bristles lacking at distal end of tarsus I (Fig. 10I). Pairs of tarsal papillae on legs 1–14, expression of short-long alternation of tarsal papillae on successive tarsomeres on legs 1–9 (sometimes legs 1–10) (Figs 6D, 9A–D, 10J); legs 10–14 (or legs 11–14) with paired long tarsal papillae (Figs 6E, 9E–H, 10K). Setal cluster associated with tarsal papillae sparse, arranged in longitudinal bands of 2–3 setae. Resilient sole hairs originate near posteromedial edge of tarsal papillae, extending to approximately one-third length of the succeeding tarsomere. — Sternites: Sternites with median swelling. Longitudinal median furrow visible, extending two-thirds length of the sternite. All sternites are scattered with setae, no hairs, spines or spiculae. — Gonopods: Female gonopods with maximum length 1.5–2.2 times maximum width; longitudinal median suture in proarthron complete (Figs 8G, 9I, 10E). Lateral margins of proarthron nearly parallel (lateral margins of the proarthron of the juvenile gonopods diverge posteriorly). Subtriangular depression on proarthron deep, lacking setae. Proarthron 1–1.5 times length of mesarthron (Figs 8G, 9I, 10E). Coarsest setae on proarthron slightly thicker than those on mesarthron apart from cluster at distomedial corner of mesarthron, this cluster usually composed of 6–10 setae (Fig. 9J, K). Sinus between mesarthron usually broadly parabolic, its apex typically weakly pointed (Fig. 9J). Width of mesarthron 0.4–0.8 times maximum width of sinus. Proarthron + mesarthron 1.7–2.2 times length of metarthron. Outer margin of metarthron arched (Fig. 9L). Ventral surface of metarthron scattered with small, pointed conical sensilla; outer margin of the metarthron bears 15–16 sensilla coeloconica, arranged roughly in a single row (Figs 9L, 9M, 10H). A few setae on dorsal side of metarthron (Figs 9L, 10E). Subanal plate drop-shaped; smooth, seta-free band in the middle of the subanal plate; setae present on outer surface of subanal plate (Fig. 8G, H). Both pairs of styliform male gonopods densely covered with setae, terminal part with short, spiniform setae between longer setae (Fig. 8H).

China (Hainan).

The specific epithet albilineata is a Latin feminine adjective. It is a compound formed from “albi-”, derived from the stem of the Latin adjective albus, meaning “white”, and “-lineata”, the feminine past participle of the Latin verb lineare (to draw a line), meaning “lined” or “striped.” The name means “white-striped,” describing the distinct white longitudinal stripe in the middle of the tergites of this species.