Selenobrachys ustromsupasius Acuña, Dumbrique, Ranido, Ragasa, Noriega, Mayor, Jr, Fadri, Wirth, Santiago-Bautista & Jr, 2025, sp. nov.
Creators: name: Acuña, Darrell C.
name: Dumbrique, Maria Mikaela U.
name: Ranido, Maricel C.
name: Ragasa, Lorenz Rhuel P.
name: Noriega, Charles Nylxon C.
name: Mayor, Anna Beatriz R.
name: Florendo Jr, Gregorio Antonio
name: Fadri, Mary Jane A.
name: von Wirth, Volker
name: Santiago-Bautista, Myla R.
name: Guevarra Jr, Leonardo A.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Theraphosidae
Selenobrachys
Selenobrachys ustromsupasius

description: Selenobrachys ustromsupasius sp. nov.
Figs 11, 12, 13, 14, 15 B – D, 16, 17, 18 A, 21 E, F
Type material examined.
Philippines: Romblon Island — Romblon Prov. • holotype ♂, UST-ARC 0002 (field # R 01-02), paratypes 4 ♂♂, 8 ♀♀, 1 j, UST-ARC 0001, 0003–0014 (field # R 01-01, R 01-03 – R 01 - 14); Municipality of Romblon, Brgy. Tambac; 12°32.0106'N, 122°17.6595'E, 200 m a. s. l., Sep 2022, AB Mayor, L De Capiz, RM De Capiz leg. • paratypes 2 ♂♂, 4 ♀♀, 10 j, UST-ARC 0015 –0030 (field # R 02-01 – R 02 - 16); Municipality of Romblon, Brgy. Guimpingan; 12°35.2478'N, 122°17.2416'E, 80 m a. s. l., 24 Feb 2023, DC Acuña, LA Guevarra Jr., CN Noriega, MJ Fadri, GA Florendo Jr., CJ Cabisuelas leg.; UST-ARC.
Diagnosis.
Selenobrachys ustromsupasius sp. nov. can be distinguished from its congener, S. philippinus comb. rest, (i) in having longer leg I than leg IV, with RF ~ 104–111; (ii) in having narrower posterior sigilla (Figs 12 B, 16 C); (iii) in having a palpal organ in males with greater palpal organ index (POI> 48), with embolus with broader basal lobe (Fig. 14 B), with thicker prolateral superior keel (PS) (Fig. 14 A, B) but stouter at tip (Fig. 14 E), and with less pronounced subtegular ridge (StR) (Fig. 14 A, B); and (iv) in having greater number of maxillary (> 365) and labial (> 608) cuspules. It also differs in color, having a brown to dark brown general body coloration (Figs 11 A, B, 19 G, H).
Description.
Holotype ♂, UST-ARC 0002 (field # R 01-02). Body length 43.18. (n = 7: 43.00–45.19) Figs 11 A, 12 – 14, 15 B – D.
Carapace (Fig. 12 A). Length, 17.41, median width 15.34, CI 88.11, CLI 65.88, CHI 22.75. Integument dark reddish brown. Caput profile low and flat, cephalic region slightly higher. Fovea procurved (Fig. 12 D), width 1.72, curve length 1.89. Distance of fovea to posterior carapace margin 4.55; distance to OT 9.68. Setation: TS (a) long, thin, pale brown setae at carapace margin, pointing anteriorly. TS (b) long, strong, dark brown setae, pale brown apically, intermixed with TS (a) and SC, at clypeus, and few at the top of OT between AMEs. TS (c) rows of short pale or dark brown setae, pale brown apically, that run along radial grooves pointing to fovea. SC (a), very short, thick, flat, pale brown scales covering anterior 1 / 2 surface of OT. SC (b), mat of long, dense, whitish acicular scales, covering lateral sides and front of OT, pointing towards OT and carapace, sparse to none on middle surface, denser on coastal surface, mostly pointing anteriorly.
Eyes (Fig. 12 C). OT length 1.94, width 2.86. Clypeus 0.5, integument dark. Eyes anterior row slightly procurved, posterior row recurved. Eyes: AME 0.61 (round), ALE 0.78 (ovoid), PME 0.44 (ovoid), PLE 0.47 (ovoid). Interocular distances: AME - AME 0.31, PLE - PLE 1.97, ALE - ALE 1.59, PME - PME 1.24, ALE - PLE 0.21, AME - ALE 0.20, AME - PME 0.12, ALE - PME 0.32, PME - PLE 0.09, AME - PLE 0.55. EI (AME) 3.50, EI (ALE) 4.48.
Chelicerae (Fig. 13 A – D). Dorsal length 8.51, dorsal width 3.79, lateral width 6.49. Fang curve length 6.68. Prolateral surface: more than upper 1 / 2 integument dark, lower surface reddish brown, with long brown fine setae, lowest portion above teeth darker and longer. Intercheliceral pegs absent but with rows of stiff setae. Retrolateral surface: integument upper 2 / 3 dark, lower surface reddish brown to amber, flat whitish scales (SC a), fine, white, cottony acicular scales (SC b), and long strong setae (TS) covering dorsal and upper retrolateral surfaces, greater anteriorly, patch of fine and long, mostly slightly curved setae at posterior area of lower retrolateral surface, patch of very fine setae with curved ends at anterior area of retrolateral surface, proximomedial setae needleform, very sparse. Long, pale reddish brown brush of setae ventrally. Teeth 11, mesoventral denticles sparse, ~ 41, on three or four rows. Lyrate region (Fig. 13 C, D): 237–248 total strikers on six to seven horizontal rows, unordered, the strongest and longest strikers on lower rows. Primary rows ~ 11 (0.80–0.83 long) long dark brown with long curved filiform ends pointing distally. Secondary rows ~ 142 (0.17–0.66), dark spiniform with short curved filiform ends pointing inward. Tertiary rows ~ 90 (0.09–0.18), short, pallid, and needleform, located above secondary rows. Long, pallid pseudostrikers present ventrally.
Maxillae (Fig. 13 E, F). Prolaterally planoconvex, anterior lobe well pronounced, cuspules on inner basoventral surface ~ 365. Stridulatory organ (Fig. 13 F): ~ 465 total bacilliform rods, in nine or ten rows, form long and dense ovoid patch, proximally truncated and distally mildly tapering (3.31 long, 1.70 high). Short bacilliform rods ~ 424, 0.22–0.53, needleform. Longer rods ~ 41, 0.55–0.77, paddle-shaped with thick and strong shafts and pointed ends, ~ 10 of which have well-defined paddle blades, located at lowest rows. Paddles flattened perpendicularly to maxillary surface. Setation: TS, brown setae, with upper part paler, present dorsally and ventrally, longest ventrally. Proximodorsal with erect fine pallid setae. Lyrate patch surrounded by fine setae. Above maxillary suture, two rows of ~ 20 stiff dark TS. SC, flat whitish scales covering dorsal surface. Retrolateral surface smooth, with rows of short semi-transparent bristles at lower margin.
Labium and sternum (Fig. 12 B, E). Labium (Fig. 12 E): length 2.30, width 3.30, integument reddish brown, paler anteriorly. Labial cuspules ~ 608, dark, at apical 1 / 3. Setation: TS (a), long brown with filiform ends, covering labium anteriorly and laterally except on cuspule cluster, longer and denser at anterior edge, all pointing anteriorly. TS (b), dark, spiniform, on posterior surface. Sternum (Fig. 12 B): sternum length 7.68, width 6.80, integument reddish brown, slightly darker at margin. Posterior sternal corner acuminate, lateral corners weakly acuminate. Labiosternal sigilla ovoid, 1.12 long and 0.40 wide, 0.72 apart. Sternal sigilla 3 pairs, ovoid. Anterior pair 0.28 long, 0.16 wide, 4.72 apart, and 0.16 away from the sternal margin adjacent to coxa I. Median pair 0.88 long, 0.24 wide, 3.88 apart, and 0.20 away from the sternal margin adjacent to coxa II. Posterior pair 1.44 long, 0.44 wide, 1.48 apart, and 1.16 away from the sternal margin adjacent to coxa III. Setation: TS (a), long and short dark spiniform setae on entire sternum, sparse on middle surface. TS (b), dark and pallid, short spiniform with filiform ends, at sternal margin. SC, flat grayish brown scales mat covering entire sternum.
Abdomen and spinnerets. Abdomen 14.70 long, 8.25 wide, ovular elongated, integument pale brown. Pedicel 1.8, pale brown, dorsally striated. Setation: TS, long brown setae, paler apically, covering entire abdomen, except book lungs and epigynal plate, denser laterally. Book lungs covered with short, pale brown spiniform setae. PTS, dark and short, covering book lungs and epigynal plate, intermixed with semi-transparent thin and short sensilla. SC, grayish brown, covering entire, sparse on book lungs and epigynal plate. All setae pointing distad. Spinnerets (Fig. 12 F): PMS 2.02 long, 0.60 wide. PLS 9.52 long (ant. 3.12, mid. 2.84, pos. 3.56), and 2.88 wide (ant. 1.32, med. 0.92, post. 0.64). Setation: TS, long brown setae, paler apically, covering dorsally and laterally. PTS, dark and short, covering ventrally, intermixed with spigots. SC, grayish brown, sparse, present dorsally.
Genitalia. Palpal organ (Fig. 14 A – E): almost 1 / 2 of palp tibia length (POI 48.35). Tegulum length 1.91, width 1.78. Embolus length 2.79, basal width 1.11, middle length 0.33, tip 0.21 wide. Tegulum globular, widest medially, subtegular ridge (StR) pronounced (Fig. 14 A, B). Embolus 146 times longer than tegulum (EMI 146.07), robust at the base (Fig. 14 A, B), tapering distally, Embolus has long and thick prolateral superior keel (PS) from base to tip (Fig. 14 A, B) but stout at the tip (Fig. 14 E); prolateral inferior keel (PI) short, emerged from the tip to rear at apical 1 / 5, located below PS and embolic opening (Op) (Fig. 14 E); apical keel (A) very short, emerged almost at the tip (Fig. 14 E); embolic opening (Op) located between PS and PI near the tip (Fig. 14 E). Basal lobe pronounced and broad, projected proximally (Fig. 14 B). Palpal tibia long and cylindrical (Fig. 15 B, C).
Legs. Leg formula: I, IV, II, III. RF ~ 110.99, LLI (I) 20.90, LLI (IV) 18.83, DLI (I) 20.85, DLI (IV) 18.67, TI (IV) 44.03, MI (IV) 108.80. Leg lengths total (fem., pat., tib., met., tar. / cym.): Palp 31.51 (11.24, 6.82, 9.72, n / a, 3.73), Leg I 64.31 (17.72, 9.63, 16.01, 13.19, 7.76), Leg II 53.39 (14.59, 7.88, 12.36, 11.65, 6.91), Leg III 45.83 (12.24, 6.31, 9.63, 11.51, 6.14), Leg IV 57.94 (15.47, 6.89, 13.86, 15.08, 6.64). Leg lateral widths (fem., pat., tib., met., tar. / cym.): Palp (2.53, 2.38, 2.24, n / a, 2.61), Leg I (4.23, 3.21, 2.85, 1.76, 1.39), Leg II (3.85, 3.16, 2.40, 1.58, 1.32), Leg III (4.19, 2.94, 2.47, 1.56, 1.25), Leg IV (3.52, 2.89, 2.17, 1.43, 0.91). Leg dorsal widths (fem., pat., tib., met., tar. / cym.): Palp (2.74, 2.50, 2.07, n / a, 2.50), Leg I (3.56, 3.36, 2.99, 1.93, 1.57), Leg II (3.38, 3.04, 2.45, 1.78, 1.40), Leg III (3.66, 2.75, 2.54, 1.73, 1.29), Leg IV (3.20, 2.52, 2.33, 1.65, 1.12). Cymbium bipartite. Tarsi I – IV transversely cracked, shows transverse weakening or mild pallid region, tar. I and tar. II more anteriorly, tar. III and tar. IV medially.
Leg setation (femora to tarsi) and spines. Setation: TS, long, dark brown setae with contrasting pale brown filiform ends, present on palp and to all legs, but sparse to all tarsi, prolateral femora I and II, and retrolateral femur IV, all pointing distad, with some erect rows on leg 1 dorsally. PTS, short and pallid, dense on ventral femur I, sparse on ventral palpal femur, prolateral to ventral patella I, and ventral femur II. FS, prolateral femur I with dense field (less dense than females) of elongated sword-like setae. SC, reflective grayish brown, covering all legs, longer and fine on all femora, pale brown on all patellae. PB, grayish, present on dorsal palpal patella but not long and dense, also present on dorsal palpal tibia but very sparse (Fig. 15 B, C). ETB, short brown setae in pair of thin inverted L-shaped clusters, starting from basolateral to dorsal Met I to II, single cluster on Met III to IV. Cymbium with single cluster dorsally that broadens basally. TB, long and short filiform intermix with ETB in two rows, longest dorsally. Rows of clavate TB, unordered, varying in size, present in all tarsi and cymbium, and intermix with tarsal ETB. CHS tiny, pale brown translucent erect sensilla tapering apically, present on the palpal and all leg femora to tarsi and intermix with tarsal and metatarsal scopulae. Spines: (dorsal-dorsoprolateral-dorsoretrolateral-ventral): Met I (0-0 - 0 - 1), Met II (0-0 - 0 - 3). Met III (0-1 - 1 - 3). Met IV (0-1 - 1 - 5).
Coxae and trochantera. Coxae: Palp coxa (see Maxillae). Lengths (coxa I, II, III, IV) 7.52, 5.80, 5.20, and 5.60. Widths (coxa I, II, III, IV) 4.00, 3.48, 3.44, 3.88. Setation: TS, long brown setae, dorsally and ventrally; strong and short spiniform setae, prolaterally on all coxae. SC (a), flat scales covering the ventral to retrolateral 1 / 2. SC (b), white, cottony, acicular scales covering the dorsal of all coxae. Patches of fine setal fringe present laterally on coxae, intermixed with short spiniform setae. Coxae I – IV have rows of short semi-translucent bristles, prolaterally, denser on coxae I and II. Trochantera: Lengths (troch. palp, I, II, III, IV) 2.12, 3.52, 3.32, 3.08, 2.72. Widths (coxa palp, I, II, III, IV) 2.48, 3.40, 2.96, 3.12, 3.28.
Scopulae and claws. Scopulae: cymbium scopulated ventrally. Tar. I, entire, but intermixed with longitudinal one or two rows of very sparse short spiniform setae. Tar. II, entire, but intermixed with longitudinal one or two rows of very sparse short spiniform setae. Tar. III, entire, but intermixed with longitudinal two or three rows of strong, long setae. Tar. IV, divided by four rows of strong, long setae. All tarsi with a bald spot ventrobasally. Met. I, almost all ventral surface covered, entire, but intermixed with longitudinal one or two rows of very sparse long setae. Met. II, most ventral surface covered, entire, but intermixed with longitudinal one or two rows of very sparse long setae. Met. III, covering 4 / 5 distally, entire, but intermixed with longitudinal one or two rows of very sparse long setae. Met. IV, covering 3 / 4 distally, divided by two or three rows of strong long setae. Claws: pair of claws present on all leg tarsi with one to three teeth on each claw. Unpaired inferior third claw 0.13, very short, present on tarsus IV (Fig. 15 D).
Color in life. Slightly dichromatic, dark on carapace and all femora, and covered with pale brown setae on leg patellae, tibiae, metatarsi, and tarsi, including trochantera, sternum, abdomen, and spinnerets (Fig. 11 A). Almost uniformly dark brown with a mild purplish blue sheen reflected by scales just after ecdysis, which fades in a few days.
Paratype ♀, UST-ARC 0005 (field # R 01-05). Body length 53.85 (n = 12: 42.56–55.13) Figs 11 B, 16, 17, 18 A, 21 E, F
Carapace (Fig. 16 A). Length 18.82, median width 15.61, anterior width 9.47, CI 82.94, LI 66.84, CHI 27.42. Integument reddish brown. Caput profile low and flat, and cephalic region slightly higher. Fovea procurved (Fig. 16 E), width 2.13, with curve length 2.22. Distance of fovea to posterior carapace margin 4.74, distance to ocular tubercle 10.67. Setation: TS (a), long, thin, pale brown setae at the margin of carapace, directed anteriorly; TS (b), long, strong, dark brown setae and pale brown apically, intermixed with TS (a) and SC (b), at clypeus, and one or two at top of OT between AMEs; TS (c), rows of short pale brown or dark brown setae, pale brown apically, that runs to radial grooves pointing to fovea; SC (a), short, flat, pale brown scales covering anterior 1 / 2 surface of OT; SC (b), mat of satiny white acicular scales covering carapace but sparse to absent medially and greater on margin, most directed anteriorly (denser and longer on male).
Eyes (Fig. 16 A, B). Ocular tubercle (OT) length 2.16, width 2.99. Clypeus 1.2. Eyes anterior row slightly procurved, posterior row recurved. Eyes: AME 0.68 (round), ALE 0.85 (ovoid), PME 0.54 (ovoid), PLE 0.52 (ovoid). Interocular distances: AME - AME 0.34, PLE - PLE 2.16, ALE - ALE 1.69, PME - PME 1.34, ALE - PLE 0.20, AME - ALE 0.19, AME - PME 0.06, ALE - PME 0.27, PME - PLE 0.20, AME - PLE 0.57. EI (AME) 3.61, EI (ALE) 4.52.
Chelicerae (Fig. 17 A – D). Dorsal length 11.48, dorsal width 4.79, lateral width 67.46. Fang curve length 8.86. Prolateral surface (Fig. 17 B): reddish brown, darker distally and paler proximally, long brown fine setae at lower surface, darker and longer at lowest portion above teeth. Intercheliceral pegs are absent but with rows of stiff setae. Retrolateral surface (Fig. 17 A): integument, upper 2 / 3 dark brown, lower surface reddish brown to amber, flat whitish scales (SC a), fine, white, cottony acicular (SC b), and long, strong tactile setae (TS) covering dorsal and upper retrolateral surface, greater anteriorly, patch of fine and long, mostly slightly curved setae at posterior area of lower retrolateral surface, patch of very fine straight setae at anterior area of retrolateral surface, proximomedial setae needle form, very sparse. Long pale reddish brown brush of setae, ventrally. Teeth 16 (including 4 uprooted and 5 smaller teeth) (0.13–0.51), mesoventral denticles dense, ~ 77, on three or four rows. Lyrate region (Fig. 17 C, D): 234–245 strikers on six or seven horizontal rows, unordered. Strongest and longest strikers on lower rows. Primary rows ~ 11 (0.86–0.95) long and dark brown, with long, curved filiform ends pointed distally. Secondary rows ~ 140 (0.19–0.67) dark and lanceolate with short curved filiform ends pointed downward. Tertiary rows ~ 89 (0.12–0.15) short, pallid, and needleform. Long, pallid pseudostrikers present ventrally.
Maxillae (Fig. 17 E, F). Prolaterally planoconvex, anterior lobe well pronounced, cuspules on inner basoventral surface ~ 365. Stridulatory organ (Fig. 17 F): ~ 370 bacilliform rods, in nine or ten rows, form a long and dense ovoid patch, proximally truncated, distally mildly pointed (3.47 long, 1.71 high). Short bacilliform rods 0.21–0.51, with pointed ends. Longer rods 0.49–0.84, paddle-shaped, with paddle blades 0.23–0.36 long and pointed ends, with thick, strong shafts slightly curved outward located at lowest rows. Paddles are flattened perpendicularly to maxillary surface. Total number of rods with paddle blades ~ 40, ~ 10 of them have well-defined paddle blades. Setation: TS, brown setae, with upper part paler, present dorsally and ventrally, longest ventrally. Proximodorsal surface with erect pallid fine setae. Lyrate patch surrounded by fine setae. Above maxilla suture with two rows of ~ 24 stiff dark TS. SC, flat whitish scales covering dorsal surface.
Labium and sternum. Labium (Fig. 16 D) length 2.76, width 3.45, integument reddish brown, paler anteriorly. Labial cuspules ~ 759 (0.05–0.08), dark, at apical 1 / 3. Setation: TS (a), long, brown with filiform ends, covering labium anteriorly and laterally except on cuspule cluster, longer and greater at anterior edge, all pointing anteriorly. TS (b), dark, spiniform, on posterior surface. Sternum (Fig. 16 C) length 8.04, width 7.88, integument pale brown, slightly darker at margin. Posterior sternal corner acuminate, lateral corners weakly acuminate. Labiosternal sigilla ovoid, 1.36 long and 0.49 wide, 1.15 apart. Sternal sigilla three pairs, ovoid. Anterior pair 0.48 long, 0.30 wide, 4.60 apart, and 0.67 away from sternal margin adjacent to coxa I. Median pair 0.48 long, 0.30 wide, 4.92 apart, and 0.52 away from sternal margin adjacent to coxa II. Posterior pair 1.64 long, 0.55 wide, 1.90 apart, and 1.38 away from sternal margin adjacent to coxa III. Setation: TS (a), long and short dark spiniform setae on entire sternum, less concentrated on middle surface. TS (b), dark and pallid, short spiniform with filiform ends, at sternal margin. SC, grayish brown flat scale mat covering entire sternum.
Abdomen and spinnerets. Abdomen 23.55 long, 16.33 wide, ovular elongated, integument pale brown. Pedicel 1.87, brown, dorsally striated. Setation: TS (a), long brown setae, paler apically, covering entire abdomen except book lungs and epigynal plate, shorter ventrally. Book lungs covered with short brown spiniform setae. TS (b), dark short paddle-like, covering entire epigynal plate densely, intermixed with semi-transparent thin and short sensilla, and long spiniform setae anteriorly. SC, flat grayish brown scales, covering entire area, darker on epigynal plate. All setae pointing distad. Spinnerets: PMS 2.40 long, 0.84 wide. PLS 10.76 long (ant. 3.72, mid. 3.08, pos. 3.96), 4.08 wide (ant. 1.68, mid. 1.32, pos. 1.08). Setation: TS (a), long brown setae, paler apically, covering dorsally and laterally. TS (b), dark short paddle-like, covering ventrally. Spigots present on all segments ventrally. SC, flat grayish brown scales, sparse, present dorsally.
Genitalia. Spermathecae unilobed, not fused. Lobe length 1.25, width 0.93, basal width 1.10, very broad and short tombstone-shaped spermathecal lobe with rounded ends and almost parallel lateral margins (Fig. 18 A). Entirely sclerotized, greater apically and weaker basally. Lobes close to each other, separated by 0.07. Epigastric fold 3.96 long.
Legs. Leg formula: I, IV, II, III. RF ~ 104.28., LLI (I) 24.43, LLI (IV) 21.84, DLI (I) 23.37, DLI (IV) 20.48, (MI (IV) 126.80, TI (IV) 50.92. Leg lengths total (fem., pat., tib., met., tar. / cym.): Palp 32.07 (10.72, 6.28, 7.92, n / a, 7.15), Leg I 61.35 (16.42, 10.08, 14.29, 11.65, 8.91) Leg II 48.54 (13.13, 8.06, 10.90, 10.10, 6.35), Leg III 42.60 (11.33, 6.30, 8.48, 10.35, 6.14), Leg IV 58.83 (15.07, 7.66, 12.39, 15.71, 8.00). Leg lateral widths (fem., pat., tib., met., tar. / cym.): Palp (3.95, 2.50, 2.68, n / a, 0.93), Leg I (4.31, 3.50, 3.02, 2.49, 1.67), Leg II (4.13, 3.28, 2.54, 1.78, 1.41), Leg III (3.69, 3.05, 2.66, 1.74, 1.33), Leg IV (4.06, 3.11, 2.86, 1.61, 1.21). Leg dorsal widths (fem., pat., tib., met., tar. / cym.): Palp (2.67, 2.42, 2.46, n / a, 1.70), Leg I (3.42, 3.66, 3.04, 2.31, 1.91), Leg II (3.20, 2.94, 2.51, 2.04, 1.73), Leg III (3.54, 2.60, 2.45, 1.89, 1.64), Leg IV (3.34, 2.79, 2.62, 1.75, 1.55). Tarsus I – V with transverse weakening, tar. I and tar. II more anteriorly, tar. III and tar. IV medially.
Leg setation (femora to tarsi) and spines. Setation: TS (a), long and short brown spiniform setae, paler on upper part, covering all over palp and legs except to median to lower prolateral palpal femur surface and leg I and II prolateral femora, longest on palpal tibia and ventral palpal femur, and all leg femora, tibiae, metatarsi, and tarsi. Leg retrolateral femur IV with stout setae. All pointing distad but erect on all ventral femora. TS (b), dark paddle-like setae, present on palp (prolateral to ventral distal femur, patella, and proximal tibia), leg I (dorsolateral and ventral femur, ventral to prolateral patella, and proximal tibia), leg II (prolateral and ventral femur, patella, and proximal tibia), and leg III and IV (ventral femora). Very dense on ventral femora I and II and prolateral tibia I and femora II. FS, prolateral femur I with a dense field of short sword-like TS (Fig. 21 F), similar to TS (b) but shorter and with pointed ends. SC, reflective, flat, grayish brown scales, pale brown on all dorsal patellae, covering all legs and palp except prolateral palpal femur proximally, which leaves an ovoid smooth surface. Other sensory setae: ETB, short brown setae in two thin inverted L-shaped clusters, starting from basolateral to dorsal Met I to II, and a single cluster on Met III to IV. TB (a), long and short filiform TB intermix with ETB in two rows, longest dorsally. TB (b) rows of unordered clavate TB, varying in size, present to all tarsi, and intermix with tarsal ETB. CHS, tiny pale brown translucent erect sensilla tapering apically, present on palpal and all leg femora to tarsi, and also intermixes with tarsal and metatarsal scopulae. Spines: (dorsal-dorsoprolateral-dorsoretrolateral-ventral): Met I (0-0 - 0 - 1), Met II (0-0 - 0 - 3). Met III (0-1 - 1 - 3). Met IV (0-1 - 1 - 3).
Coxae and trochantera. Coxae: Palp coxa (see Maxillae). Lengths (coxa I, II, III, IV) 8.42, 7.28, 5.72, 6.12. Widths (coxa I, II, III, IV) 4.40, 4.04, 3.88, 4.28. Setation: TS, long brown setae dorsally and ventrally, strong and short spiniform setae prolaterally on all coxae. SC (a), flat scales covering ventral to retrolateral 1 / 2. SC (b), white cottony acicular covering dorsal of all coxae. Patches of fine setal fringe present laterally on coxae, intermixed with short spiniform setae. Coxae I – IV have rows of short semi-translucent bristles, prolaterally, denser on Coxae I and II. Trochantera: Lengths (troch. palp, I, II, III, IV) 2.84, 4.32, 3.88, 3.12, 3.64. Widths (coxa palp, I, II, III, IV) 2.92, 3.76, 3.20, 3.04, 3.52.
Scopulae and claws. Scopulae (left): Palp tarsus undivided but parted. Tarsus I, entire, but intermixed with longitudinal one or two rows of very sparse short spiniform setae. Tarsus II, entire, but intermixed with very sparse longitudinal one or two rows of short spiniform setae. Tarsus III, entire, but intermixed with longitudinal two or three rows of strong long setae. Tarsus IV, entire, divided by four rows of strong long setae. All tarsi with a bald spot ventrobasally. Met. I covered almost all ventral surfaces, entire, but with longitudinal one or two rows of very sparse long setae. Met. II, covered almost all ventral surface, entire, but with longitudinal one or two rows of very sparse long setae. Met. III, covered 4 / 5 distally, entire, but with longitudinal one or two rows of very sparse long setae. Met. IV, covered 3 / 4 distally, divided by two or three rows of strong long setae. Claws: pair of claws present on all leg tarsi with one to three teeth on each claw. Tarsus IV with a short unpaired third inferior claw.
Color in life. Females are mildly dichromatic (Fig. 11 B), with dark brown on carapace, abdomen, palp, and all legs, contrasted by dark femora on all legs and palp. Dark brown legs (except femora) are topped with pale brown setae, sparsely hirsute. Legs and abdomen reflect (by scales) a deep, mild purplish blue sheen. Generally, uniformly dark with a mild bluish sheen after ecdysis, which fades in a few days. Coloration changes, becoming pale brown, as the exoskeleton ages before ecdysis.
Natural history and distribution.
Mature males were collected in September, and females with egg sacs (Fig. 19 E) were found in February. Burrows, not self-dug, were found under piles of coconut husks (Fig. 19 B, G) piles and crevices of metamorphosed limestones (marble) at the roadside embankments (Fig. 19 C – F). They are also found in the beach forest of Bon Bon Beach in the northwestern coast of Romblon Island. The spiders were found on the burrow entrance at night, waiting for prey to ambush. This species is known only to occur in Romblon Island, Philippines (Fig. 22).
Etymology.
The specific epithet is a masculine adjective derived from the combined names of the collaborating academic institutions and an organization of the project in which this study is involved, namely, the University of Santo Tomas (UST), Romblon State University (RSU), Mindanao State University-Iligan State University (MSU-IIT), University of the Philippines-Diliman (UPD), and the Philippine Arachnological Society, Inc. (PASI), attached with the Latin suffix - us.
description: Published as part of Acuña, Darrell C., Dumbrique, Maria Mikaela U., Ranido, Maricel C., Ragasa, Lorenz Rhuel P., Noriega, Charles Nylxon C., Mayor, Anna Beatriz R., Florendo Jr, Gregorio Antonio, Fadri, Mary Jane A., von Wirth, Volker, Santiago-Bautista, Myla R. & Guevarra Jr, Leonardo A., 2025, Taxonomic revalidation of Selenobrachys Schmidt, 1999 and Chilocosmia Schmidt & von Wirth, 1992 based on morphological and molecular analyses (Araneae, Theraphosidae), with the description of a new species from Romblon Island, Philippines, pp. 139-193 in ZooKeys 1233 on pages 139-193, DOI: 10.3897/zookeys.1233.128056