Chilocosmia dichromata Schmidt & von Wirth 1992
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
Chilocosmia
Chilocosmia dichromata

description: Chilocosmia dichromata Schmidt & von Wirth, 1992, comb. rest.
Figs 2, 3, 4, 5, 6, 20 C, F, 21 I, J
Type material examined.
Indonesia — West New Guinea • holotype ♀, SMF 37099-84; Sorong; SMF.
Other material examined.
Indonesia — West New Guinea • 2 ♂♂ SMNS Aran-004182 and Aran-004183, 5 ♀♀, SMNS Aran-004184, Aran-004185 and Aran-004162 –004164, 3 j, SMNS Aran-004186; Sorong; 00°47'36.4"S, 131°26'32.8"E, F. Schneider leg., 2014; SMNS.
Diagnosis.
See genus diagnosis.
Description.
Male (SMNS Aran-004182). Body length 38.50 (n = 2 38.50–38.62).
Carapace (Fig. 2 B). 17.2 long, 14.9 wide, anterior width 8, 95, cephalic height 4.9, cephalic region 11.3 long, thoracic region 4.79 long. CI 86.62, CLI 65.69, CHI 28.48. Fovea width 1.85, curve length 2.11, procurved (Fig. 2 E). Carapace has four pairs of furrows, mainly covered with yellowish brown setae directed towards fovea, lateral profile low and flat, and integument dark brown. Setation: TS (a), rows of very short pale yellowish brown setae covering entire carapace, directed towards fovea and OT anteriorly. Posterior surface of OT with few long pale brown TS. TS (b), long pale yellowish brown setae at carapace margin, anterior margin pale brown. SC (a), brown flat scales sparsely covering OT. SC (b), sparse, pale yellowish brown, acicular scales covering carapace, anteriorly.
Eyes (Fig. 2 D). Ocular Tubercle 3.12 long, 2.28 wide, OT integument entirely dark. AME round, rest of the eyes ovoid. Anterior row of eyes slightly procurved, posterior row of eyes recurved. Eyes: AME 0.69, ALE 0.79, PME 0.46, PLE 0.61. Interocular distances: AME - AME 0.38, ALE - ALE 1.94, PME - PME 1.48, PLE - PLE 2.21, AME - ALE 0.13, AME - PME 0.22, AME - PLE 0.56, ALE - PLE 0.23, ALE - PME 0.47, PME - PLE 0.14. EI (AME) 4.01, EI (ALE) 4.59.
Chelicerae (Fig. 3 A – C). length 9.72, dorsal width 3.27, lateral width 5.99, fang curve length 7.29. Teeth 12, mesoventral denticles sparse 45. Setation: TS, long pale brown setae on dorsal and upper 1 / 2 retrolateral surface, longer anteriorly. Lower 1 / 2 of retrolateral surface posteriorly with rows of pallid filiform setae and anteriorly with patch of pallid needleform setae. Mesoretrolateral surface with rows of very sparse setae basally spiniform and anteriorly needleform. Mesoprolateral surface with intercheliceral setae, arcuate strip of rows of pallid needleform setae originating basally. Lower 1 / 2 prolaterally sparsely covered with setae, brown needleform at lower rows, and pale brown filiform at upper rows. SC, flat, translucent, pale brown scales, covering dorsal and upper retrolateral surface. Integument mostly dark brown. Cheliceral strikers (Fig. 3 C): 111, 0.20–1.03, dark, long spiniform with filiform ends.
Maxillae (Fig. 3 D, F). Prolateral maxilla 6.33 long, 4.02 wide laterally, 3.58 wide ventrally. Maxilla prolaterally planoconvex, anterior lobe well pronounced, integument orangey brown, dark dorsally, basoventral cuspules 212. Lyra (Fig. 3 D): lyrate patch, 2.24 long, 1.38 high, total rods 190, 10 or 11 rows, surrounded by very fine setae, denser above and distally. Short rods form an arcuate strip of patch. Longest club-shaped rods in lowest row 13, 0.27–0.78. Setation: TS, pale brown setae, longer ventrally, stronger at distodorsal margin. Lyrate patch surrounded by fine setae. Above maxillary suture, rows of ~ 13 stiff dark TS. SC, brownish white flat scales covering dorsally. Retrolateral surface smooth, with rows of short semi-transparent bristles at the lower margin.
Labium and sternum (Fig. 2 C, F). Labium: 2.30 long, 3.12 wide. Integument orangey brown, dark at posterior margin, anterior 1 / 3 with cuspules 371. 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), brown, short needleform below cuspule cluster. Sternum: 8.2 long, 6.93 wide integument yellowish brown. Posterior sternal corner acuminate, lateral corners weakly acuminate. Setation: TS (a), long pale brown spiniform setae, pale apically, on entire sternum, but very sparse. TS (b), short pale brown setae covering sternum entirely. TS (c) fine, pallid, and short spiniform, at sternal margin. SC, brownish white flat scale mat densely covering entire sternum. Labiosternal sigilla 1.07 long, 0.34 wide, 0.83 apart. Sternal sigilla 2 pairs, median sigilla 0.69 long, 0.35 wide, 3.91 apart and 0.58 away from sternal margin adjacent to coxa II, posterior sigilla 1.08 long, 0.42 wide, 1.59 apart and 1.77 away from sternal margin adjacent to coxa III (Fig. 2 C).
Abdomen and spinnerets. Abdomen: 17.56 long, 10.09 wide. ovular elongated, integument pale brown. Setation: TS (a), long, pale brown with darker bases, needleform, on entire abdomen, shorter ventrally, pallid on book lungs. TS (b), pallid short paddle-like, on book lungs and sparse on epigynal plate. SC, overlapping pale brown translucent scales covering entire abdomen. Spinnerets: PMS 2.39 long, 0.84 wide, PLS, anterior 2.30 long, 0.71 wide, median 1.82 long, 0.99 wide, posterior 3.65 long, 1.39 wide. Setation: TS (a), long, pale brown with darker bases, needleform, on dorsal PMS and PLS. TS (b), dark and short, pale brown paddle-like, intermixed with spigots, on PMS and PLS ventrally. SC, brownish white flat scales covering PLS dorsally.
Genitalia (Figs 4 A – C, 5 A – E). Palpal Organ: almost 3 / 4 of palp tibia length (POI 73.70). Tegulum 2.67 long, 2.14 wide, twisted, widest medially, subtegular projection very weakly pronounced (Fig. 5 A – D). Embolus length 3.30, width 0.54 basally, tip 0.10 wide (EMI 123.56), base robust, tapering distally, curved retrolaterally and ending to a weakly tip. There is a prolateral inferior keel (PI) and prolateral superior keel (PS) in the apical third of the embolus (Fig. 5 E). The apical keel (A) is located at the tip of the embolus and is semicircular in shape (Fig. 5 E). Embolic opening (Op) located between PS and PI near the tip. Basal lobe is not present.
Legs. Leg formula: IV, I, II, III. RF ~ 91.77, LLI (I) 26.54, LLI (IV) 21.15, DLI (I) 23.18, DLI (IV) 18.49, MI (I) 76.25, MI (IV) 132, TI (I) 69.67, TI (IV) 45.45. Leg lengths (fem, pat, tib, met, tar / cym): Palp 26 (10, 4.2, 8.1, -, 3.7) Leg I 61.3 (16.5, 8.1, 16, 12.2, 8.5) Leg II 55.6 (15, 7.1, 13, 12.5, 8) Leg III 49.5 (13, 6, 9, 14.5, 7) Leg IV 66.8 (17, 6, 15, 19.8, 9). Leg lateral width (fem, pat, tib, met, tar / cym): Palp (3.24, 2.92, 3.21, -, 2.46) Leg I (4.15, 3.51, 3.62, 2.82, 2.17) Leg II (4.33, 3.36, 3.16, 2.37, 1.94) Leg III (4.88, 3.45, 3.04, 2.45, 1.91) Leg IV (3.99, 3.47, 3, 1.96, 1.71) Leg dorsal width (fem, pat, tib, met, tar / cym): Palp (3.19, 2.93, 3.21, -, 2.88) Leg I (3.38, 3.30, 2.84, 2.18, 2.51) Leg II (3.40, 3.13, 2.59, 2.05, 2.07) Leg III (4.22, 3.17, 2.42, 1.90, 2.13) Leg IV (3, 40, 3, 06, 2.54, 1.89, 1.46). Cymbium bipartite. Tarsi IV transversely cracked apically.
Leg setation and spines. Setation (femur to tarsus): TS on all legs pale brown and short, longer on all metatarsi dorsally, femur of rear legs ventrally and on all tibia ventrally, dense on tibiae I and II, ventrally. There are only pale brown TS. PB is also not present on the palps. There are only pale brown TS. SC, brownish. Other sensory setae: ETB, pair of thin inverted L-shaped cluster of short dark brown setae, basoretrolateral on Met. I and II, single cluster on Met III. Cymbium with 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 II (0-0 - 0 - 2). Met III (0-1 - 1 - 2). Met IV (0-0 - 1 - 4).
Coxae and trochantera. Coxae: Length (coxa I, II, III, IV), 8.68, 6.05, 6.76, 6.83. Width (coxa I, II, III, IV), 4.46, 3.68, 4.17, 4.59. Setation: TS, long brown setae, dorsally and ventrally; strong and short spiniform setae, prolaterally and retrolaterally on all coxae. Trochantera: Length (troch. palp I, II, III, IV), 3.20, 3.21, 2.92, 3.38, 4.03. Width (troch. Palp I, II, III, IV), 2.77, 4.15, 3.88, 3.55, 3.72.
Scopulae and claws. Scopulae: cymbium scopulated ventrally. Tar. I, entire, with very few longer setae. Tar. II, entire, with very few longer setae. Tar. III, entire, with very few longer setae. Tar. IV, in the basal 1 / 4 divided by three or four long setae. The tarsus is cracked in the apical 1 / 4. Met. I covered almost all ventral surfaces, entire, but with a few very sparse long setae. Met. II, almost all ventral surface covered, entire, but with a few very sparse long setae. Met. III, almost all ventral surface covered, entire, but with a few very sparse long setae. Met. IV, covering 90 % of ventral surface, divided by two or three rows of strong long setae. Claws: longest tarsal IV claw 1.70, no inferior third claw (Fig. 5 G) (but present on some specimens; Fig. 5 F), but there are a few large teeth on the claws whose number can vary from one claw to another.
Color in life. The opisthosoma and legs, except for the coxa and trochanter, are black in color (Fig. 2 A). Coxa and trochanter as well as the carapace and the chelicerae basal segment are bronze-colored (Fig. 2 A, C). The underside of the cephalothorax is also black. The area around the eye tubercle, as well as two diverging hairless stripes on the carapace, which frame the head, are dark brown in color. On each chelicerae basal segment there is also an elongated dark brown stripe in the middle of the bronze coloration.
Variation.
The third inferior claw is present or almost absent on some specimens and varies in length if present, which is also observed in other species in this study.
Etymology.
Greek dýo chrómata (δύο χρώματα) means two colors, which refers to the bicolored orange and black coloration of this species (Schmidt and von Wirth 1992).
Natural history and distribution.
The spiders live in tubes in the primary forest whose entrances are well camouflaged and difficult to find (Fig. 6 B). In the habitat of C. dichromata comb. rest., there is apparently only this species of tarantula (Fig. 6). All tubes were filled with water to a depth of ~ 10 cm. The temperature in the tubes was 24–26 ° C. The water in the tubes was ~ 2 ° C cooler. Probably the spiders flee into the water when disturbed. Known only from Sorong, West New Guinea (now Southwest Papua Province), Indonesia.
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