A revision of the South American species of the ant-mimicking spider genus Myrmecotypus O. Pickard-Cambridge, 1894 (Araneae: Corinnidae: Castianeirinae) Silva-Junior, Cláudio J. Bonaldo, Alexandre B. Zootaxa 2024 2024-12-20 5555 4 451 496 Silva-Junior & Bonaldo 2024 [151,455,151,178] Arachnida Corinnidae Myrmecotypus Animalia Araneae 37 488 Arthropoda species atratoides sp. nov.   Fig. 23A–E   Type material.  Holotype, ♀, BRAZIL: Amazonas, Manaus, Reserva Ducke,  IX.1995, T. Gasnierleg. ( IBSP, IB-14493).   FIGURE 23.  Myrmecotypus atratoides  spec. nov.A–C, G–H; holotype female (IBSP, IB-14493); D–F, paratype variation forms (ICN-Ar-288). Afemale, dorsal view; Bsame, lateral view; Csame, ventral view; Dfemale, dorsal view; Esame, lateral view; Fsame, ventral view; G, female epigyne, ventral view; Hsame, dorsal view. Abbreviations: CO, copulatory opening, CD, copulatory duct; ST II, secondary spermathecae; ST I, primary spermathecae; FD, fertilization duct. Scale: 1 mm.   Paratypes: EQUADOR: Napo: 20km E. Puerto  Napo, Alinahui, 01°00’S, 77°25’W,  150 m, 1♀,  XI–XII.1995, E.S. Rossleg. (CASENT-9036802).  COLOMBIA: Meta Restrepo, Vod Tarey,  29.X.1989, A. Arevaloleg. (ICN-Ar-288).   Etymology.The specific name derives from the combination of the specific epithet of the ant species  Cephalotes atratusand the suffix “-oīdēs” (Latin), referring to the superficial similarity of this species with members of the  atratus-clade of this genus of ants.  Note.Unlike all other described species of  Myrmecotypus,  M. atratoides  spec. nov.has a different color and constriction pattern on the carapace, resembling ants from the genus  CephalotesLatreille, 1802(Tribe Attini), while, according to Cushing (1997)and Perger & Rubio (2020), several other species of the genus resemble ants from the Tribes Camponotini and Dolichoderini.   Diagnosis.Females of this species resemble those of  M. tahyinanduand  M. rapaxoides  spec. nov.by the presence of recurved transverse ridge with a large marginal sclerotized area but differs from these and all other  Myrmecotypusby the wide constriction on the carapace over legs I and II ( Fig. 23B), whereas the constriction is only over leg II or between I and II in other species.   Description.Female ( holotype). Total length 12.76. Carapace 6.91 long, 2.57 wide. Sternum 3.20 long, 1.15 wide.Abdomen 5.09 long, 4.51 wide. Eye diameters:AME 0.20, ALE 0.09, PME 0.09, PLE 0.08. Eye inter-distances: AME-AME 0.12, AME-ALE 0.17, ALE-PLE 0.30, PME-PME 0.41, PME-PLE 0.31, AME-PME 0.26. Carapace dark, cephalic region red, yellow hairs over entire carapace surface ( Fig. 23A). Endites dark, with promargin white, labium dark, with anterior margin white. Chelicerae brown, two promarginal teeth of different sizes and two retromarginal teeth equal and equidistant. Sternum dark, covered by feathery hairs. Abdomen globose, dark gray, with moderately small, dark dorsal scute ( Fig. 23A, B). Ventral scute absent and tracheal scute present ( Fig. 23C). All coxae and femora black. Tibiae I and II brownish; metatarsi yellowish, with proximal area brownish; tarsi brown, with proximal area yellowish; tibiae, metatarsi and tarsi III and IV darker. Leg measurements: I—femur 2.50 / tibia 2.39 / metatarsus 1.76; II—femur 2.65 / tibia 2.35 / metatarsus 1.72; III—femur 2.88 / tibia 1.99 / metatarsus 1.76; IV—femur 4.65 / tibia 3.14 / metatarsus 2.81. Spination: I-femora do0-1-1-0, rl0-0-0-1; tibiae ve2-2-2 (3-3); metatarsi ve2-2/ II-femora do0-1-1-0, rl0-0-0-1; tibiae ve2-2-2; metatarsi ve2-2/ III-femora do1-1-1; pl1-0-1, rl1-0-1; tibiae do0-0-1, pl0-1-1, rl0-1-1, ve2-2; metatarsi pl1-1-1, rl1-1-1, ve2-2-2-/ IV-femora do1-0-1-1, pl0-0-0-1, rl0-0-0-1; tibiae do0-0-1, pl1-0-1, rl1-0-1, vep 1-0-1; metatarsi pl1-1-0-1, rl1-1-0-1, ve2-2. Copulatory openings under fine sclerotized and continuous ridge, posterior in relation to secondary spermathecae, CD curved at 90-degree angle, STII larger than ST I ( Fig. 23D, E).  Variation.One of the paratypes(ICN-Ar-288) presents yellowish coloration on the cephalic region as well as on the legs, and pale yellow on the abdomen. Coxa II is yellowish-white with darkened distal margins ( Fig. 23F).   Other material.Only the types.   Distribution.Known from three localities in Brazil, Ecuadorand Colombia( Fig. 27). 5004791313 1995-09 T, IBSP Gasnier Brazil Reserva Ducke Amazonas Manaus 37 488 IB-14493 1 1 holotype 5004791327 [199,730,151,177] E. Puerto Ecuador Napo 38 489 1 Napo paratype 5004791304 1995-11 1995-12-31 1995-11 E. S. Ross Ecuador 150 -1.0 Alinahui 1308 -77.416664 38 489 1 1 Napo paratype 5004791337 1989-10-29 A. Arevalo Colombia Vod Tarey Restrepo 38 489 1 Meta paratype