Selenobrachys philippinus Schmidt 1999
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 philippinus

description: Selenobrachys philippinus Schmidt, 1999, comb. rest.
Figs 7, 8, 9, 10, 18 B, 20 B, E, 21 G, H
Type material examined.
Philippines: Negros Island — Negros Occidental Prov. • holotype ♀, SMF 39202-84; Mambucal (now Mambucal Resort and Wildlife Sanctuary); SMF.
Other material examined.
Philippines: Negros Island — Negros Occidental Prov. • ♂, PASI ara 0006, 9 ♀♀, 8 j, UST-ARC 0112 – UST-ARC 0127 (field # NOM 1 A-01 – NOM 1 A-16); Mambucal Resort and Wildlife Sanctuary; 365 m a. s. l., 26 Jun 2023, burrows under metamorphic rock boulders and crevices, LA Guevarra, DC Acuña, CN Noriega, R Enguito, LJS Villaflor leg.; PASI / UST -ARC • ♀, SMNS Aran-004192, 5 ♂♂, SMNS Aran-004187 – Aran-004191; Mount Canlaon; 2010, JM Verdez leg.; SMNS.
Diagnosis.
Selenobrachys philippinus comb. rest. can be distinguished from its congener, S. ustromsupasius sp. nov., (i) in having longer leg IV than leg I (RF ~ 89–98); (ii) in having broader posterior sigilla on the sternum (Fig. 7 E); (iii) in having a palpal organ in males with lower palpal organ index (POI <42), with embolus with narrower basal lobe (BL) (Fig. 10 B), with thinner prolateral superior keel (PS) (Fig. 10 A, B) but broader at the tip (Fig. 10 E, F), and with less pronounced subtegular ridge (StR) (Fig. 10 A, B); and (iv) in having lesser number of maxillary (<305) and labial (<471) cuspules. It also differs in color, having an orange to orangey brown general body coloration (Fig. 7 A; Schmidt 1999).
Description.
Male (PASI ara 0006). Body length 42.07 (n = 6: 41.43–43.98).
Carapace (Fig. 7 B). 17.51 long, 14.94 wide, anterior width 10.24, cephalic height 3.8, cephalic region 11.6 long, thoracic region 5.91 long. CI 85.32, CLI 66.25, CHI 21.70. Fovea width 2.27, curve length 2.43, procurved. Carapace has four pairs of weak furrows, lateral profile low and flat, and integument orangey brown, darker anteriorly. Setation: TS (a), rows of very short pale yellowish brown setae covering entire carapace, directed towards fovea and anteriorly to OT. Posterior surface of OT with pale brown short TS (a). TS (b), long pale yellowish brown setae at carapace margin, anterior margin light brown. SC (a), very short light brown flat scales sparsely covering OT. SC (b), pale yellowish brown acicular scales covering carapace, dense anteriorly, very sparse medially.
Eyes (Fig. 7 D). Ocular tubercle 2.09 long, 2.73 wide, integument dark, paler anteriorly. AME round, rest of the eyes ovoid. Anterior row of eyes slightly procurved, posterior row of eyes recurved. Eyes: AME 0.61, ALE 0.76, PME 0.51, PLE 0.51. Interocular distances: AME - AME 0.26, ALE - ALE 1.55, PME - PME 1.25, PLE - PLE 1.98, AME - ALE 0.18, AME - PME 0.13, AME - PLE 0.64, ALE - PLE 0.31, ALE - PME 0.35, PME - PLE 0.14. EI (AME) 3.48, EI (ALE) 4.34.
Chelicerae (Fig. 8 A – C). length 8.92, dorsal width 3.68, lateral width 6.28, fang curve length 7.48. Teeth 11, mesoventral denticles sparse ~ 35. Setation: TS, long pale brown setae on dorsal and upper 1 / 2 retrolateral surface, longer anteriorly. Lower 1 / 2 of retrolateral surface posteriorly with a patch of pallid filiform setae, anteriorly needleform. Mesoretrolateral surface with rows of very sparse setae basally spiniform, anteriorly needleform. Mesoprolateral surface with intercheliceral setae in arcuate strip of rows of pallid needleform setae originating basally. Lower 1 / 2, prolaterally, sparsely covered with brown needleform setae, filiform above. SC, flat, translucent, brownish white scales, covering dorsal and upper retrolateral surface. Cheliceral strikers (Fig. 8 C): Primary rows, ~ 16, 0.65–0.91 dark, long spiniform with filiform ends. Secondary rows, ~ 136, 0.21–0.55, dark long and short spiniform. Tertiary rows, ~ 114, 0.16–0.23, pallid very short needleform setae. Pseudostrikers long and pallid, and present ventrally.
Maxillae (Fig. 7 F, G). Prolateral maxilla 7.47 long, 4.53 wide laterally, 3.75 wide ventrally. Maxilla prolaterally planoconvex, anterior lobe well pronounced, integument orangey brown, darker dorsally, basoventral cuspules ~ 305. Maxillary lyra (Fig. 7 G): lyrate patch dense, in ovoid shape, truncated proximally, mildly tapering distally, 3.90 long, 2.10 high, total rods ~ 539, on 10–11 rows, surrounded by very fine setae, denser above and distally. Short bacilliform rods ~ 496, 0.24–0.39, needleform. Longer rods ~ 43, 0.49–0.85, paddle-shaped with pointed ends, which ~ 12 have well-defined paddle blades, and thick strong shafts slightly curved outward, located at the lowest rows. Setation: TS, pale brown spiniform setae, longer ventrally, stronger at distodorsal margin. Lyrate patch surrounded by fine setae. Above maxillary suture, two rows of ~ 15 stiff dark spiniform TS. Retrolateral surface is smooth, with rows of short semi-transparent bristles at lower margin. SC, flat whitish yellow-brown scales covering dorsal surface.
Labium and sternum (Fig. 7 C, E). Labium: 2.32 long, 3.15 wide. Integument orangey brown, darker posteriorly, anterior 1 / 3 with cuspules ~ 471. Setation: TS (a), long, pale brown with pale filiform ends, covering labium anteriorly and laterally except on cuspule cluster, longer and greater at anterior edge, all pointing anteriorly. TS (b), dark, short needleform below cuspule cluster. Sternum: 8.20 long, 6.93 wide, integument yellowish brown. Posterior sternal corner acuminate and lateral corners weakly acuminate. Setation: TS (a), long pale brown spiniform setae, pale apically, on entire sternum but sparse medially. TS (b), fine, pallid, and short spiniform, at sternal margin. SC, white flat scale mat covering entire sternum. Labiosternal sigilla 1.49 long, 0.38 wide, 0.75 apart. Sternal sigilla 3 pairs, anterior sigilla 0.34 long, 0.22 wide, 4.53 apart, and 0.26 away from sternal margin adjacent to coxa I, median sigilla 0.81 long, 0. 34 wide, 3.93 apart, and 0.50 away from sternal margin adjacent to coxa II, posterior sigilla broad (Fig. 7 E), 1.40 long, 0.58 wide, 1.60 apart, and 1.17 away from sternal margin adjacent to coxa III.
Abdomen and spinnerets. Abdomen: 18.69 long, 7.65 wide. ovular elongated, integument pale citron brown. Setation: TS (a), long, citron brown with darker bases, needleform, on entire abdomen, shorter ventrally, and pallid on book lungs. TS (b), rows of pallid and short paddle-like on book lungs and sparse on epigynal plate. SC, dense, overlapping flat, translucent, pale brown scales lightened by pale citron integument producing an orangey brown mat covering entire abdomen. Spinnerets: PMS 2.24 long, 0.74 wide, PLS, anterior 2.56 long, 1.52 wide, median 2.84 long, 1.12 wide, posterior 3.76 long, 1.00 wide. Setation: TS (a), long, citron brown with darker bases, needle form, on dorsal PMS and PLS. TS (b), dark and short, pale brown paddle-like TS, intermixed with spigots, on PMS and PLS ventrally. SC, flat brownish white scales covering PLS dorsally.
Genitalia (Figs 9 A – C, 10 A – E). Palpal Organ: approximately 2 / 5 of palp tibia length (POI 41.45). Tegulum 1.92 long, 1.81 wide, globular, widest medially, subtegular ridge (StR) weakly pronounced (Fig. 10 A, B). Embolus length 2.42, width 1.20 basally and 0.37 medially, tip 0.16 wide, Embolus length 1.26 times longer than tegulum length (EMI 126.04), base robust, tapering distally, curved retrolaterally and ending to a broad tip. Embolus has a long and stout prolateral superior keel (PS) (Fig. 10 A, B) but broad at tip (Fig. 10 E, F); has prolateral inferior keel (PI) short, emerged from the tip to rear at apical 1 / 5, below PS and embolic opening (Op) (Fig. 10 E, F); apical keel (A) very short, emerged almost at the tip; embolic opening (Op) located between PS and PI near the tip (Fig. 10 E, F). Basal lobe pronounced but not broad, projected proximally (Fig. 10 A, B).
Legs. Leg formula: IV, I, II, III. RF ~ 91.94, LLI (I) 20.93, LLI (IV) 16.39, DLI (I) 19.97, DLI (IV) 16.23, MI (I) 80.99, MI (IV) 124.10, TI (I) 59.78, TI (IV) 44.41. Leg lengths (fem, pat, tib, met, tar / cym): Palp 31.96 (11.08, 6.46, 10.47, -, 3.95) Leg I 66.41 (18.11, 9.92, 16.73, 13.55, 8. 1) Leg II 58.56 (15.7, 8.16, 14.59, 12.86, 7.25) Leg III 51.81 (13.04, 6.59, 11.54, 13.63, 7.01) Leg IV 72.23 (17.64, 7.68, 16.8, 20.85, 9.26). Leg lateral width (fem, pat, tib, met, tar / cym): Palp (2.64, 2.34, 2.56, -, 2.35) Leg I (4.05, 3.61, 3.06, 1.9, 1.28) Leg II (3.49, 3.35, 2.58, 1.45, 1.37) Leg III (3.61, 2.8, 2.39, 1.75, 1.2) Leg IV (3.77, 3.08, 2.34, 1.55, 1.1) Leg dorsal width (fem, pat, tib, met, tar / cym): Palp (2.63, 2.27, 2 -,, 2.38) Leg I (3.75, 3.08, 2.96, 1.84, 1.63) Leg II (3.31, 2.69, 2.54, 1.65, 1.35) Leg III (3.43, 2.61, 2.44, 1.72, 1.31) Leg IV (3.25, 2.76, 2.48, 1.96, 1.27). Cymbium bipartite. Tarsi I – IV transversely cracked, shows transverse weakening or pallid region, tar. I and tar. II more anteriorly, tar. III and tar. IV medially.
Leg setation and spines. Setation (femur to tarsus): TS (a), brown spiniform setae on all legs, longer TS pale brown, longer on all femora, ventrally and on palp patella and tibia, thicker on leg III and IV, dense citron brown on tibiae I and II, ventrally. TS (b), short and pallid paddle-like setae, dense on ventral femur I, sparse on ventral palpal femur, ventral patella I, and ventral femur II. FS, prolateral femur I with dense field (less dense than females) of elongated sword-like TS. PB, thin layer of short, flat, pale brown, scales, present on dorsal palpal patella and dorsal palpal tibia but very sparse (Fig. 9 D). SC, flat whitish scales, darkened by reddish brown integument, covering all legs. Other sensory setae: ETB, pair of thin inverted L-shaped clusters of short pale brown setae, starting from basolateral to dorsal Met. I and II, single cluster on Met III and IV. Cymbium with a single cluster dorsally that broadens basally. 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 in all tarsi, 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 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 - 4). Met IV (0-1 - 1 - 3).
Coxae and trochantera. Coxae: Length (coxa I, II, III, IV), 8.16, 7.88, 6.78, 7.31. Width (coxa I, II, III, IV), 4.49, 3.97, 4.27, 4.21. Setation: TS (a), long pale brown setae, covering dorsal and ventral surfaces; TS (b), strong and short spiniform setae, prolaterally on all coxae; TS (c), patches of fine setal fringe present laterally on coxae, intermixed with TS; TS (d), Coxae I – IV have rows of short semi-translucent bristles, prolaterally, denser on coxae I and II. SC (a), flat, grayish brown scales, covering the ventral to retrolateral 1 / 2; SC (b), white, cottony, and acicular, covering the dorsal of all coxae. Trochantera: Length (troch. palp I, II, III, IV), 2.78, 3.95, 3.02, 1.84, 2.77. Width (troch. palp I, II, III, IV), 2.59, 3.99, 3.52, 3.44, 3.62.
Scopulae and claws. Scopulae: cymbium scopulated ventrally. Tar. I, entire, but intermixed with one or two longitudinal rows of very sparse short spiniform setae. Tar. II, entire, but intermixed with one or two longitudinal rows of very sparse short spiniform setae. Tar. III, entire, but intermixed with two or three longitudinal rows of short spiniform setae. Tar. IV, divided by four rows of strong and long spiniform setae. Met. I ventral surface almost completely scopulated, entire, but with one or two longitudinal rows of very sparse long setae. Met. II, almost all ventral surface covered, entire, but intermixed with one or two longitudinal rows of very sparse long setae. Met. III, covering 4 / 5 distally, entire, but intermixed with one or two longitudinal 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. Tarsal IV claw, 2.27, with unpaired inferior third claw. 0.20.
Color in life. Monochromatic. The reddish brown integument is lightened by whitish scales creating a uniform orange to orangey brown body coloration (Fig. 7 A).
Variation.
The third inferior claw is absent or almost absent on some specimens and varies in length if present, which is also observed in other species in this study.
Natural history and distribution.
Spiders are found roaming outside near their burrows at night. Burrows, not self-dug, are found near streams under metamorphic rock boulders and crevices on mountain slopes. Known only from Mambucal Resort and Wildlife Sanctuary (at the foot of Mt. Canlaon) and Sipalay City (West et al. 2012) in Negros Occidental, Negros Island, Philippines. Reports from the internet in the islands of Panay, Guimaras, and Cebu are unverified and may represent a separate island endemic species of Selenobrachys.
Etymology.
The specific epithet is a masculine adjective derived from the country locality, the Philippines (Schmidt 1999).
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