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Caecilia wilkinsoni sp. nov. Figs. 1–6; Table 1. Caecilia tenuissima Taylor, 1973: Lynch (2000: 329) {urn:lsid:zoobank.org:pub: 8CDE156F-86BC-4EF8-B812-C51C70A431DA} Holotype. ICN 58477, an adult male collected by Gladys Cárdenas-Arévalo and Rafael Ángel Moreno Arias at Quebrada El Hojal, Consejo Comunitario Unión del Río Rosario, vereda La Chorrera, Tumaco, Nariño, Colombia, 6 April 2006. 1° 45’ 52’’ N, 78° 45’ 56’’ W, 14 m. a.s.l. (Figs. 1–3). Paratype. UVC 7686, an adult female obtained by Liliana Peláez at Estero San Antonio, corregimiento Flor de la Brisa, vereda Robles, municipio El Charco, Nariño, Colombia, 8 October 1984. 2° 26’ 48.1’’ N, 78° 11’ 44.5’’ W, 10 m. a.s.l. (Figs. 4–6). Distribution. Currently Caecilia wilkinsoni sp. nov. is known only from the holotype and paratype localities of southwestern Colombia in the Pacific lowlands of the Litoral Pacífico, in Tumaco, and from Estero San Carlos, El Charco, Nariño, between 10– 14 m.a.s.l. Diagnosis. Caecilia wilkinsoni sp. nov. differs from C. atelolepis, C. attenuata Taylor, 1968, C. caribea, C. corpulenta Taylor, 1968, C. crassisquama Taylor, 1968, C. degenerata, C. guntheri, C. inca Taylor, 1973, C. macrodonta, C. occidentalis, C. orientalis, C. pachynema (Günther, 1859), C. pulchraserrana, and C. subdermalis in having (vs lacking) secondary grooves. Caecilia wilkinsoni sp. nov. differs from congeners that have secondary annular grooves as follows. Caecilia disossea Taylor, 1968 (216–262 primary grooves and 16–34 secondary grooves) is the only member of the genus that has more primary and fewer secondary grooves than C. wilkinsoni sp. nov. (190–195 primary grooves and 51– 71 secondary grooves). Caecilia aprix also has more primary grooves (234) but an overlapping secondary groove count (58) with the new species. Caecilia bokermanni (180–192 primary grooves and 15–21 secondary grooves), C. gracilis Shaw, 1802 (183–204 primary grooves and 11–21 secondary grooves), C. occidentalis (186–221 primary grooves and 0–15 secondary grooves), and C. thompsoni (187–240 primary grooves and 26–42 secondary grooves) have overlapping counts of primary grooves and fewer secondary grooves than the new species. Caecilia wilkinsoni sp. nov. has more primary annular grooves than C. abitaguae Dunn, 1942 (137–148 primary grooves and 0–5 secondary grooves), C. albiventris Daudin, 1803 (144–147 primary grooves and 45–53 secondary grooves), C. antioquiaensis (171 primary grooves and 4 secondary grooves), C. armata Dunn, 1942 (186 primary grooves and 92 secondary grooves), C. dunni Hershkovitz, 1938 (124 primary grooves and 67 secondary grooves), C. epicrionopsoides (139–163 primary grooves, 21–40 secondary grooves), C. flavopunctata Roze & Solano, 1963 (155 primary grooves and 27 secondary grooves), C. guntheri (111–132 primary grooves and 0–10 secondary grooves), C. isthmica (131–147 primary grooves and 12–21 secondary grooves), C. leucocephala (118–142 primary grooves and 17–45 secondary grooves), C. mertensi Taylor, 1973 (142 primary grooves and 48 secondary grooves), C. museugoeldi Maciel & Hoogmoed, 2018 (152 primary grooves and 26 secondary grooves), C. nigricans (157– 189 primary grooves and 32–62 secondary grooves), C. perdita (139–152 primary grooves and 64–83 secondary grooves), C. subnigricans (151–161 primary grooves and 17–31 secondary grooves), C. subterminalis Taylor, 1968 (170 primary grooves and 16 secondary grooves), C. tentaculata (122–137 primary grooves and 30–42 secondary grooves), and C. volcani Taylor, 1969 (112–124 primary grooves and 14–32 secondary grooves). Caecilia nigricans (159–195 primary grooves, 27–65 secondary grooves, length in width 32.6–80.4 times)— another species from the Pacific lowlands and Cordillera Occidental of Colombia —has overlapping counts of primary and secondary grooves, and attenuation index values with C. wilkinsoni sp. nov. (190–195 primary grooves, 51–71 secondary grooves, length in width 65.6–74.7 times), but C. nigricans has a terminal shield or ‘’cap’’ at the posterior end of the body that is barely interrupted dorsoventrally by the last few grooves of the body vs an entirely segmented terminal portion of the body in the new species, meaning that only the small disk and vent are free of grooves in C. wilkinsoni sp. nov. (Figs. 3, 6). Dermal scales obtained at the posterior end of the body of Caecilia nigricans are subcircular vs subrectangular in C. wilkinsoni sp. nov. Moreover, in life, Caecilia nigricans is mostly blue but C. wilkinsoni sp. nov. is mostly black. The new species is readily differentiated from C. tenuissima by having many more secondary grooves (51–71 vs 9). In addition, the new species has a head that is narrower than its mid-body width (vs noticeably wider than the body in C. tenuissima Taylor, 1973: 221, fig. 32); though in our experience a head much wider than mid-body is a rare condition within the genus, and the holotype of C. tenuissima appears to be somewhat desiccated from available photographs, suggesting this condition might be artefactual. Another difference between the species might be that in C. tenuissima the eye is not visible externally, while in C. wilkinsoni sp. nov. the eye is visible through translucent epidermis. There are no transverse grooves on the collars of C. tenuissima according to the original description (Taylor, 1973) but C. wilkinsoni sp. nov. has well-defined transverse grooves present on both collars. Squamation also differs between these two species, in that C. tenuissima has dermal scales only towards the terminus while C. wilkinsoni sp. nov. has dermal scales throughout its body. Caecilia wilkinsoni sp. nov. (190–195 primary grooves, 51–71 secondary grooves, length in width 65.6–74.7 times) is superficially similar to C. thompsoni (187–240 primary grooves, 26–42 secondary grooves, length in width 62–100 times), an endemic species of the Magdalena Valley of Colombia and the adjacent Cordilleras Central and Oriental, as well as the largest caecilian in the World, achieving a notable total length of 1767 mm (Arredondo-Salgar, 2007). However, the new species has more secondary annular grooves than C. thompsoni (51–71 vs 26–42) and has small, flattened (not protruding) narial plugs on the tongue (vs protruding narial plugs in C. thompsoni). Description of the holotype. General condition of the specimen is good given that the individual was found dead, though it has two dorsal flesh wounds; one between primary grooves 116–121 and another between primary grooves 157–168. A ventral longitudinal incision was made between primary grooves 166–188 to search for sexual organs, and a few dermal pockets towards the terminus were opened to search for dermal scales. An adult male with a total body length of 590 mm and a mid-body width of 7.9 mm, length divided by width 74.7 times. Head (7.7 mm) slightly narrower than body. In lateral view, top of head slightly vaulted (not straight), upper margins of the mouth very slightly concave, lower margins of the mouth straight. Snout blunt in dorsal view, rounded in ventral view, but generally pointed (bullet-like) in profile, it extends beyond the mouth by 2 mm. Nostrils oval and broadening posteriorly, visible in dorsal view but not visible in ventral view, closer to tentacular opening than to eye, distance between nostril and tentacular opening 1.6 mm, distance between eye and nostril 4.5 mm, distance between nostrils 2.8 mm. Eyes small, 0.5 mm in diameter, covered by translucent epidermis and clearly visible in dorsal and lateral view but not visible in ventral view. Eye lies closer to the commissure of the mouth (4.2 mm) than to the nostril (4.5 mm). Distance between eyes 5.0 mm, less than distance from tip of snout to eye level (5.5 mm). Tentacular opening circular in outline, elevated above the skin, positioned below and posterior to the nostril, closer to margin of the mouth than to the nostril, barely visible in dorsal view. Collars well defined, the first is smaller than the second and bears a short groove dorsally, the second collar bears two incomplete grooves dorsally and dorsolaterally. The first and second nuchal grooves are complete, but the third nuchal groove incomplete dorsally and ventrally. Body width is even from collars (8.1 mm) to mid-body, where it then begins to taper, reaching a minimum body width of 6.5 mm at the fourth fifth of the total body length, before becoming abruptly stouter (8.1 mm) at the terminus, i.e. equivalent in width to the collars. Primary grooves 195, only the last 10 prior to the vent completely encircle the body; secondary grooves 71, all on posterior half of body, the last 7 prior to the vent completely encircle the body. No terminal shield. Vent very small, and transverse, bordered by 6 denticulations anteriorly and 7 posteriorly, no anal glands in region surrounding vent. Dermal scales present as far anteriorly as the first primary groove, small (0.7 mm wide by 0.4 mm long), and oval; those closest to the terminus are very large (2.3 mm wide by 2.1 mm long), subrectangular, thicker and broader at the margin of inception with the dermal pocket. No trace of subdermal scales within the connective tissue of the skin. All teeth monocuspid, pointed and slightly recurved, mandibular teeth considerably larger and more recurved than maxillary teeth. Four dental series are present: the premaxillary-maxillary series has 7-1-8 teeth, posterior ones notably smaller; the vomeropalatine series has 10-1-8 teeth, decreasing in overall size posteriorly; the dentary series has 8-8 teeth, very large, recurved, decreasing in overall size posteriorly, and show signs of tooth replacement; the inner mandibular series has 2-2 teeth, small, pointed, slightly oblique, and partially concealed by the gums. Choanae circular, 1.5 mm apart, diameter of each choana is 0.7 mm. Small, flattened, black-ish narial plugs present on the tongue, these are darker in contrast to the generally whitish color of the mouth. Coloration in life does not differ much from coloration in preservative. Main body coloration according to the field notes by the collectors of the holotype is dark purple on the dorsal surfaces, gradually becoming slightly olive on the ventral surfaces. Only the nostrils, tentacular openings, lips and vent have a contrasting pale cream color. Dermal scales are gray. No median ventral stripe. Variation. In profile, the snout of the holotype is blunt but that of the paratype is rounded. The eye lies closer to the commissure of the mouth than to the nostril in the holotype, but equidistant between the commissure of the mouth and the nostril in the paratype. The vent is situated flush inside the surrounding disc in the holotype but situated in a slight depression (concave) in the paratype; the anterior margin of the vent of the paratype has two very small anal glands, unlike the holotype; the width of the disc surrounding the vent is smaller in the holotype but larger in the paratype. The paratype differs from the holotype by having 5 denticulations on the anterior and posterior margins of the vent vs 6 anterior denticulations and 7 posterior denticulations in the holotype. The attenuation index values indicate that the holotype is slenderer than the paratype (74.7 vs 65.6: Table 1). The gums of the paratype are very thick and conceal most of the teeth on all four dental series, with only their protruding ‘tips’ being noticeable; this condition is not present in the holotype. The choanae are circular in the holotype but subcircular in the paratype. Moreover, indications of teeth replacement in the form of dark, asterisk-like markings adjacent to emerging teeth were detected on the gums of the holotype but not the paratype. Lastly, it appears to us that the paratype has dried out at least once in the past 39 years and this made us chose the ICN specimen as the holotype. Etymology. This species is named after Dr. Mark Wilkinson, Merit Researcher at the Natural History Museum in London, U.K., in recognition of his life-long dedication to the study of Gymnophiona. His numerous, highquality caecilian studies have provided a path for all aspiring ‘gymnophionologists’ to follow. Natural history. Unknown, although the field notes associated with the holotype indicate that this individual was found dead along a road at 12:00 hours in the surroundings of a stream. The paratype was found alive approximately 50 cm below the surface.

Synapturanus sacratus sp. nov. Synapturanus sp. “Jirijirimo” Synapturanus rabus Fouquet et al.., 2021a Holotype (Fig. 5). ICN 56890 (JDL28952), adult female, collected at the Departamento Amazonas, “area no municipalizada” La Victoria, Comunidad Jirijirimo, (00°02′30″S, 70°57′W, 136 m), within Parque Nacional Natural Yaigojé Apaporis, Colombia, collected on march 21, 2009 by John D. Lynch and Jorge Kayuanari. Paratopotypes. Females: ICN 56893 (JDL 28935), cleared and double-stained specimen, ICN 56889 (JDL 28951) (Fig. 3); males ICN 56892 (JDL 28934) and ICN 56895 (JDL 28973), all adult specimens were collected with the holotype. Referred specimen. ICN 56891(JDL 28953) and ICN 56894 (JDL 28933) juveniles collected along with the type series. Diagnosis: A species of Synapturanus diagnosed by the following combination of characters: 1) SVL small size, adult females 16.6, 17.3 mm (χ = 17.0, n = 2); adult males SVL 14.0, 15.0 mm (χ = 14.5, n = 2), 2) stout and ovoid body, 3) head narrower than body, snout pointed in dorsal view, rounded in lateral view, and ventrally distinctly projecting beyond the anterior edge of the upper jaw, 4) symphysis of lower jaw with an unpigmented notch and external nares with a wide and unpigmented rim, 5) tympanum slightly visible, 6) vocal slits absent, 7) rounded choanae, equal in diameter to the unpigmented rim of the external narin, 8) vomerine teeth absent, 9) hand formula III>IV>II>I, hand digits becoming thinner towards their distal ends, rounded or slightly pointed finger-tips, fingers bordered by a thin fringe, interdigital membrane absent, 10) subarticular tubercles absent, thenar tubercle small and elongated, palmar tubercle indistinct, 11) adult males bear a gland on the distal internal surface of the anterior forearm closer to the wrist and visible dorsally, 12) relative length of toes IV>III>V>II>I, toes are thin and subcylindrical, distal tip rounded, except on toe I that is distinctly pointed, fringes not evident, toe webbing absent,13) inner metatarsal tubercle small and elongated, outer metatarsal tubercle absent, subarticular tubercles absent, 14) knee, heel, and wrist with skin folds, 15) cephalic groove distinct, across the head, over the tympanum and reaching the throat barely beyond the jaw articulation, 16) in life dorsal surfaces and flanks uniformly brown or pale brown, occipital groove light brown, 17) canthal stripe distinct and dull cream, extending continuously from the rostral tip, over the nare and eye; stripe distinct over the shoulder and then broken along the flank, 18) ventral surfaces brown to grayish, hands and feet dark brown, articular surfaces and distal tips of digits unpigmented, 19) forearm gland lighter than the background in preserved specimens, scattered along the inner forearm up to the middle. Synapturanus sacratus sp. nov. can be distinguished from S. rabus (traits in parenthesis) by its smaller size, adult females SVL 16.9 and 17.3 mm (vs. 17.2-19.0 mm) and adult males SVL 14.0 and 15.0 mm (vs. 16.2-16.6 mm). The HL/END ratio in S. sacratus sp. nov. is 2.8 in average for both sexes, it is smaller than HL/END ratio in in S. rabus (3.4 in average for both sexes). Synapturanus sacratus sp. nov. (as recorded in J.D. Lynch’s field notes) have a conspicuous and continuous canthal stripe that becomes discontinuous over the body flanks (vs. a white or pale cream line along the canthus rostralis may extend onto the body). Synapturanus sacratus sp. nov. also lacks spotting on posterior legs (vs. most specimens have irregular spots on one or both legs), and dorsal surfaces are light brown to brown (vs. dark brown). Synapturanus sacratus sp. nov. is smaller than S. latebrosus sp. nov. (traits in parenthesis), adult females SVL 16.9 and 17.3 mm (vs. 20.0-22.0 mm) and adult males SVL 14.0 and 15.0 (vs. 18.1-19.0 mm). Synapturanus sacratus sp. nov. has a longer tibia, 42% of SVL (vs. 37%), and eyes larger judging by the ED/END ratio, 0.75 (vs. 0.55 in average for both sexes). Synapturanus sacratus sp. nov. has a conspicuous and continuous cream canthal stripe that becomes discontinuous over the body flanks (vs. canthal stripe formed by very small cream spots that does not extend beyond the arm). Synapturanus sacratus sp. nov. with SVL 14.0-15.0 mm in males, is considerably smaller than S. mirandariberoi (SVL 27.0- 31.7 mm in males), S. salseri, (SVL 23.7-26.4 mm in males), S. zombie (SVL 37.0- 40.6 mm in males), S. mesomorphus (SVL 22.9-26.0 mm in males), and S. ajuricaba (SVL 29.3-33.2 mm in males) and smaller than S. danta (SVL 17.6-17.9 mm in males). Synapturanus sacratus sp. nov. lacks any pattern of speckles, spots or blotches on the back present to a greater or lesser extent in those species. In S. sacratus sp. nov., the forearm gland is scattered and reaches up to the middle vs. protruding and concentrated towards the wrist in S. salseri. Description of Holotype. An adult female with unpigmented eggs in the oviduct (the largest ca. 1.5 mm), body smooth, triangular in dorsal view and small (SVL = 16.6 mm); head triangular, but almost as wide as long (HW = 4.3 mm, HL = 4.5 mm), snout tip acuminate, snout projects beyond the anterior edge of upper jaw (SL/SW= 0.6); nostrils with a distinct and light colored rim, directed laterally; the eye–nostril distance slightly greater than the eye diameter (END = 1.6 mm, ED = 1.1 mm), canthus rostralis poorly defined dorsally, loreal region concave marked bellow by a distinct groove that reaches from the antero–ventral edge of eye to the posteroventral edge of nostril, inter–orbital area concave, IOD = 1.9 mm; lacking occipital fold, a distinct shallow groove is visible behind the eyes running over the tympanic area and barely exceeds the lower jaw; tympanum small, poorly distinguishable in life but distinct in the preserved specimen, tympanum diameter = 0.7 mm; tongue thin on free edges and as wide as the oral cavity; vomerine teeth absent; oval choanae widely separated and slightly medially slanted anteriorly. Anterior and posterior limbs short and robust, hands without interdigital membranes, finger relative length III>IV>II>I, distally pointed and with thin fringes, subarticular tubercles absent, subarticular area light colored, thenar tubercle elongated to oval, located at the base of finger I, palmar tubercles not distinct; distinct folds on knee and heel, less distinct on wrist and metatarsal area; toes cylindrical, thin, narrowly fringed, and expanded distally, distal tip rounded, toe I distally pointed; subarticular tubercles absent, inner metatarsal tubercles elongated, small, at the base of finger I; toe relative lengths IV>III>V>II>I; tibia length TBL = 6.9 mm, about 41% of snout–vent length. Live coloration (Fig. 5). Dorsal surfaces brown, dull cream canthal stripe continuing, but interrupted, along flank, dark brown iris, cephalic groove light brown, fingers and toes dark brown with light colored articular surfaces, venter brown to grayish. Coloration of Preserved Specimens. Specimens have lost their coloration; overall all specimens are white to light cream. However, we note that in specimen ICN 56890 (Fig. 5 A, B, and C) there is a light brown coloration at the site where the label was removed and which was not discolored by light. Measurements of Holotype (mm). SLV 16.6; HL 4.5; HW 4.3; HL/ESD 1.8; SL/SW 0.6, TD 0.7, ESD 2.6, END 1.6, ED 1.1, ED/END 0.7, TBL 6.9, IOD 1.9, TBL/SVL 0.4. Variation in the type series. Measurement data of the type series are given in (Table 1, Appendix 2). According to the field notes (JDL), the dorsal coloration varies in shade of brown, from almost black to pale brown. Ventral coloration is not detailed, in three specimens, one of them the holotype, is described as brown to grayish, in other two specimens as mostly gray, which probably means that the depigmented area is extensive. In two adult males (ICN 56892, 56895) glandular tissues are noticeable as white dots, although specimens are decolored. Etymology. Latin, a noun in apposition, meaning sacred, alludes to the sacred sense that animals have for indigenous Amazonian peoples, particularly in the Yaigoje territory, currently designated as the Yaigojé-Apaporis National Natural Park. Distribution (Fig. 4). Synapturanus sacratus sp. nov. is known only from the type locality Tadpole and Advertisement Call. Unknown Natural History. The specimens were detected by their movements and collected among leaf litter in the afternoon, in a terra firme forest, that means a forest that does not flood., Published as part of Osorno-Muñoz, Mariela, Gutiérrez-Lamus, Doris L., Lynch, John, Keeffe, Rachel, Caicedo-Portilla, José Rancés, Chan, Kin Nok, Tonini, João F. R. & De Sá, Rafael O., 2023, Three new species of the Synapturanus rabus complex (Microhylidae: Otophryninae) in Colombia with a review of the genus Synapturanus, pp. 151-196 in Zootaxa 5258 (2) on pages 161-163, DOI: 10.11646/zootaxa.5258.2.1, http://zenodo.org/record/7777048

Synapturanus latebrosus sp. nov. Synapturanus sp. “ Caquetá ” Holotype (Fig. 3). SINCHI-A 839 (MOM 2517), adult female, collected at finca El Cairo, vereda Sinaí, Municipio Morelia, Departamento Caquetá, Colombia, (01°23′31.7″ N, 75°45′06.2″ W), ca. 278 m., on August 4, 2011 by Yunner Fabian González, Diego Huseth Ruiz, Doris Laurinette Gutiérrez, and Mariela Osorno-Muñoz. Paratopotypes. SINCHI-A 840-841 (MOM 2518-2519), adult females, and SINCHI-A 842 (MOM 2520), cleared and double-stained specimen, SINCHI-A 843-845 (MOM 2521-2523) adult males, all collected with the holotype. Paratypes. Female SINCHI-A 2678 (JARM 139) (Fig. 3B) and male SINCHI-A 2679 (JARM 140) a cleared and double-stained specimen, collected at hacienda Villa Mery, vereda Sinaí, Municipio Morelia, Departamento Caquetá, Colombia (01°24′00.1″ N, 75°43′52.3″ W), 218 m., on December 16, 2015; female SINCHI-A 2703 (JARM 172), collected at vereda La Mono, Municipio Belén de los Andaquíes, Departamento Caquetá, Colombia, (01°18′27.8″ N, 75°48′13.9″ W), ca. 262 m., on February 18, 2016; females: SINCHI-A 5642–5643 (JARM 220- 221) collected at vereda Alto Caldas, Municipio Florencia, Departamento Caquetá, Colombia (01°39′N, 75°37′W), ca. 560 m., on 01 April, 2016; female SINCHI-A 5671 (JARM 254) collected at finca Alsacia, vereda la Primavera, Municipio Florencia, Departamento Caquetá, Colombia (01°39′ 4.87″ N 75°37′4.7″ W), ca. 530 m., on April 23, 2016, by Julián Andrés Rojas Morales, and Fabián Andrés Cabrera Vargas. Females: SINCHI-A 258–259 (MOM 1840 -1841) (Fig.3A), collected at vereda La Recreo, Municipio Solita, Departamento Caquetá, Colombia (0°55′39.2″ N, 75°40′35″ W), ca. 220 m., collected by Hernándo Trujillo on October 09, 2009. Referred specimens. Males SINCHI-A 846–847 (MOM 2524-2525), female SINCHI-A 848 (MOM 2526), all juveniles collected along with the type series, male SINCHI-A 5665 (JARM 248) collected at finca Alsacia, vereda la Primavera, Municipio Florencia, Departamento Caquetá, Colombia (01°39′ 4.87″ N 75°37′4.7″ W), ca. 530 m. on April 23, 2016, by Julián Andrés Rojas Morales, and Fabián Andrés Cabrera Vargas. Diagnosis. A species of Synapturanus diagnosed by the following combination of characters: 1) SVL median size: adult females 20.0–22.0 mm (χ = 20.9 ± 0.3, n = 8), adult males 18.1–19.0 (χ = 18.7 ± 0.3, n = 3 mm), 2) stout and elongated body, 3) head narrower than body, snout pointed in dorsal view, rounded in lateral view, and ventrally distinctly projecting beyond the anterior edge of the upper jaw, 4) symphysis of lower jaw with an unpigmented notch and external nares bear a wide and unpigmented rim, 5) tympanum indistinct, tympanic annulus visible below the skin, particularly its anteroventral edge, 6) vocal slits absent, 7) choanae rounded, larger in diameter than the unpigmented rim of the external nares, 8) vomerine teeth absent, 9) hand formula III>IV>II>I, digits becoming thinner towards their distal ends, rounded or slightly pointed finger tips, fingers bordered by a thin fringe, interdigital membrane absent, 10) subarticular tubercles absent; thenar tubercle elongated, palmar tubercle rounded with undefined edges, 11) adult males bear an elongated gland on the internal surface of the anterior forearm extending half of its length and broader at the wrist, 12) toe lengths IV>III>V>II>I, toes are thin and subcylindrical with a slight distal rounded or lanceolate widening, except toe I which is pointed, toes narrowly fringed, fringes more distinct distally and around the distal expansion, toes without webs, 13) inner metatarsal tubercle small and elongated, outer metatarsal tubercle absent, subarticular tubercles absent, subarticular spots unpigmented on toes, 14) skin folds on knee, heel, and wrist, 15) cephalic groove distinct, extending over the tympanum reaching and slightly extending beyond the lower jaw, 16) in life, upper surfaces of body uniformly brown, lighter brown on the area of the cephalic groove, tympanum brownish, and body flanks orange with a greyish brown ventral area, 17) light canthal stripe present or absent; if present, dorsal to the nares and the eyes, canthal stripe continuous or broken into a series of variable size spots; confluent or not on the distal tip of snout; posteriorly, the canthal stripe could reach the area over the tympanum or above the shoulder, 18) ventral surfaces overall brown, darker on edges of mandible, snout, arms, and hidden surfaces of legs and feet; lighter on thighs, chest, and edges of abdominal region; medially the belly has a narrow and irregular shaped whitish and translucent area, hands and feet dark brown; thenar, internal metatarsal tubercles, subarticular surfaces and distal digits without coloration, 19) elongated forearm gland cream-colored in preserved specimens extending from the wrist to half the length of the forearm. Synapturanus latebrosus sp. nov. differs from S. rabus (traits in parenthesis) by its larger size, adult females SVL 20.0-22.0 mm (vs. 17.2-19.0 mm), adult males SVL 18.1-19.0 mm (vs. 16.2-16.6 mm), a shorter tibia length TBL/SVL 38% in females and 37% in males (vs. 41% in both sexes). Eyes are smaller in S. latebrosus sp. nov. ED/ SVL is 54% (vs. 73%) and the ratio of the eye diameter to the eye-nare distance is also smaller, ED/END females χ = 0.5 (vs. 0.8), ED/END males χ = 0.6 (vs. 0.9) (Tables 2 and 3). In life, S. latebrosus sp. nov. has greyish ventral flanks (vs. overall dark brown); canthal stripe, if present, extending to the shoulder area (vs. canthal stripe may extend onto the body); posterior limbs without spotting (vs. most specimens have irregular light spots on one or both legs), tympanum partially hidden (visible tympanum). Synapturanus latebrosus sp. nov. males are smaller (SVL 18.1-19.0 mm) than S. mirandariberoi (SVL males 27.0- 31.7 mm), S. salseri, (SVL males 23.7-26.4 mm), S. zombie (SVL males 37.0- 40.6 mm), S. mesomorphus (SVL males 22.9-26.0 mm), and S. ajuricaba (SVL males 29.3-33.2 mm); S. latebrosus is larger than S. danta (SVL males 17.6-17.9). Adults of Synapturanus danta and S. latebrosus sp. nov. have a uniform dark brown dorsal coloration in life whereas the dorsum of S. mirandariberoi, S. salseri, S. zombie, S. mesomorphus, and S. ajuricaba have noticeable mottled patterns made up of speckles, spots, or blotches. The forearm gland is not conspicuous in life in Synapturanus latebrosus sp. nov. and S. rabus (i.e., gray-brown, similar to the rest of the arm), whereas in S. salseri and S. mirandariberoi it was described as a pale wrist gland contrasting with the darker coloration of the rest of the arm (Pyburn, 1976). Furthermore, the gland of S. salseri is protuberant on the dorsal and inner area of the distal forearm and becoming slightly triangular with its apex towards the posterior forearm; in S. latebrosus the gland is slightly wider on the wrists and narrowing posteriorly, in some specimens reaching the midpoint of forearm. Description of the Holotype. An adult female with two large, unpigmented ovarian eggs (3.6 and 4.0 mm diameter), body smooth, slightly ovoid in dorsal view, SVL = 21.5 mm; head triangular in shape, broader than longer (HW = 5.9 mm, HL = 5.5 mm); snout tip acuminate, snout projects beyond the anterior edge of the upper jaw (SL/SW = 0.6), nostrils with a distinct light rim, directed laterally, the distance from the eye to the nostril is 2.0 mm, being twice the diameter of the eye; canthus rostralis defined, slightly concave, loreal region marked by a distinct groove that extends from the anteroventral edge of eye to the posteroventral edge of nostril, eyes small and slightly protruding, interorbital area concave, IOD = 2.5 mm; occipital groove indistinct across the head and tympanum and visible just beyond the jaw; tympanum mostly concealed, anteroventral edge of tympanic ring barely visible, upper jaw distinctly projecting beyond lower one, with an unpigmented median notch in the anterior end of the lower jaw; the tongue is as wide as the oral cavity, its posterior edges are thin and wide; vomerine teeth absent; choanae round and widely separated. Anterior and posterior limbs short and robust, hands without interdigital membranes, finger relative lengths III>IV>II>I, fingers narrowing distally with distal tips pointed or rounded, slightly fringed, subarticular tubercles absent, subarticular area light colored, thenar tubercle elongated to oval, light colored and located at the base of finger I; distinct fold on knee and heel, less distinct folds also on wrist and metatarsal area; toes overall subcylindrical and slightly broader and rounded distally, fringes noticeable in toes I, II and distally in toes III, IV, V, interdigital membrane absent, in lateral view the distal tip of the digits are slightly flattened, subarticular areas light colored without subarticular tubercles, inner metatarsal tubercle very small, elongated, placed at base of toe I, outer metatarsal tubercle absent, toe formula IV>III>V>II>I; tibia length 8.3 mm, about 39% of snout–vent length. Live coloration. Dorsal surfaces uniformly brown, except the cephalic groove that is lighter; ventral body flank greyish brown; lateral head anterior to the arm light brown, rim of nares and tip of snout grey; tympanum brown/ slightly orange; iris dark brown, canthal stripe formed by very small and discontinuous cream spots that do not reach the shoulder, ventral surface brown, belly with a narrow, medial, and unpigmented area; dorsal surfaces of hands and feet brown, articulation and distal tips of digits unpigmented, ventrally dark brown with unpigmented subarticular areas; a black spot on the external region of the right wrist. Coloration of Preserved Specimens. Dorsal surfaces brown, light brown around the occipital groove on top head, anterior body flank brown, medial and posterior body flank brown-cream, ventral surfaces of throat, chest, arms and legs light brown cream, central belly light cream, ventral surfaces of hands and feet dark brown, unpigmented subarticular surfaces, and tips of digits cream-colored (Fig. 4). Measurements of Holotype (mm). SLV 21.5, HL 5.5, HW 5.9, HL/ESD 1.6, SL/SW 0.6, ESD 3.5, END 2.0, ED 1.0, ED/END 0.5, IOD 2.5, TBL 8.3, TBL/SVL 0.4 Variation in the type series. Measurement data of the type series are given in Table 2 and Table S2. Overall, the type series agrees with the holotype coloration. Two adult females (SINCHI-A 840 and SINCHI-A 5643) lack canthal stripes, three adult males (SINCHI-A 843-845) and five females (SINCHI-A 841, SINCHI-A 2678, SINCHI-A 2703, SINCHI-A 5642 and SINCHI-A 5671) have a canthal stripe being less distinct in the holotype. The medial unpigmented area of belly is variable, in two females (SINCHI-A 840 and SINCHI-A 841) it extends toward the ventral flanks, in males the unpigmented medial area bears a few small brownish dots. Etymology. Latin adjective, meaning ignored, alluding to the ecological and behavioral habits that make the species imperceptible and probably even allow it to live in forest fragments, as small as those found in the type locality. Distribution (Fig. 4). The northernmost locality currently known for Synapturanus latebrosus sp. nov. is the Municipio Florencia, Departamento Caquetá; likely the species has a continuous distribution from the Municipio Morelia and Belén de los Andaquíes to Municipio Solita, north of the Caquetá River. Tadpole and Advertisement Call. Unknown Natural History. The holotype and paratopotypes of Synapturanus latebrosus sp. nov. were collected in a fragment of primary forest (Synapturanus latebrosus sp. nov. Overall, the skull of the genus Synapturanus is well ossified, with very little cartilaginous areas, mostly restricted to the nasal capsule and tympanic ring. Osteological description of Synapturanus latebrosus sp. nov. is based on male specimen SINCHI-A 2679, variation with male SINCHI-A 842 is noted and compared with an adult female of S. sacratus sp. nov. (ICN 56893). The skull of S. latebrosus sp. nov. is overall triangular, slightly longer than wide (Fig. 9A, B, and C) and widest at the level of the jaw articulation. The jaw articulation lies at the most anterior edge to the otic capsule. The planum anterorbitalis is ossified and oriented anterolaterally forming the posterolateral walls of the nasal capsules and the anterior wall of the orbits. The auditory capsules, except its most anteroventral edge that is mostly cartilaginous, and the crista parotica are fully ossified. Between the anteroventral cartilaginous edge of the otic capsule and the crista parotica, lies a large and cartilaginous operculum; by transparency a large fenestra ovalis is clearly visible. From the most anterior edge of the operculum and running horizontally, between the crista parotica and the cartilaginous anterior edge of the otic capsule, lies the ossified columella. The columella then bends slightly ventrally towards the squamosal, before reaching the posterior edge of the squamosal, it articulates with a cartilaginous externa plectri that connects with the cartilaginous tympanic ring. The tympanic ring is not complete, but lack its dorsoposterior third. Endocranium. Sphenethmoid. The paired sphenethmoid are well developed, fused into a single bone, ossified, and form the anterolateral wall of the neurocranium and the anterior margin of the optic fenestra. Dorsally, the sphenethmoid is mostly covered by the nasals and frontoparietals and only visible between the nasals and the frontoparietals. Ventrally, it is visible anteriorly and posteriorly on both sides of the cultriform process of the parasphenoid and forming the ventral border of a very large optic fenestra. Anteriorly it does not reach the posterior border of the choanae. Posterolaterally, the sphenethmoid indistinguishable fuses with prootic and surrounds the optic fenestra. Prootics and exoccipitals. The prootics are fused with the exoccipitals contributing to the posterior part of the braincase, both are well ossified. The prootic ossifies on the posterolateral wall of the neurocranium, forming the dorsal and posterior margin of the optic foramen and entirely enclose the prootic foramen. Dorsally, their anteromedial margins are overlapped by the frontoparietals. Ventrally, the medial and posterior margins of the prootic are overlapped by the parasphenoid. The prootics also form the anterior and ventrolateral walls of the otic capsules; dorsally they form the epiotic eminences. The epiotic eminences are ossified, large, and visible; medially they fuse gradually to the skull. Most of the ossified crista parotica does not extend beyond the level of the otic capsule; however, a small distinct extension is found on the anterolateral corner of the crista parotica. The otic capsule is mostly ossified except in its most anteroventral area. A relatively large prootic foramen lies on the anteroventral surface of the otic capsule. In anurans, usually smaller oculomotor and trochlear foramina are found between the optic fenestra and prootic fenestra; these two foramina are not visible in S. latebrosus, and likely were integrated to the large optic fenestra. The exoccipitals form the posterior part of the otic capsules, the margins of the foramen magnum, and the occipital condyles. Dorsally, the exoccipitals are largely overlapped by the frontoparietals and ventrally by the alae and posteromedial process of the parasphenoid. The exoccipitals are only visible forming the dorsal and ventral edge of the foramen magnum and the occipital condyles. The occipital condyles bear oval-shaped articular surfaces. Plectral apparatus. The plectral apparatus is found ventral to the crista parotica. The columella (pars media plectri) is a long, cylindrical bone, that proximal to the operculum has an expanded base, and runs almost horizontally and then it bends slightly and gradually ventrally towards the squamosal to about half the height of the squamosal. Distally, it connects with the cartilaginous pars externa plectri which is surrounded by a dorsally incomplete and wide ring, the cartilaginous tympanic annuli. The proximal end of the columella contacts with the anterodorsal edge of the cartilaginous operculum. The operculum is well developed, cartilaginous, and occludes the large fenestra ovalis. Exocranium. Frontoparietals. The broad, large, and paired frontoparietal bones are narrowly separated medially along their length and completely roofing the frontoparietal fenestra. The frontoparietals do not contact with the nasal bones and overlap the sphenethmoid. The anterior tip of the frontoparietals is close to the midline and from there they slant outwardly and posteriorly to the anterodorsal edge of the orbit. Posteriorly the frontoparietals extend over the prootic, partially overlap the epiotic eminences, and the exoccipitals. In specimen SINCHI 842, the separation of the frontoparietals is much narrower on its posterior 1/3. Nasal. The paired nasals are extensive and well-ossified bones, they cover the nasal capsule and the sphenethmoid, they are medially separated, and do not contact with the frontoparietals. From the midline, they extend posteriorly slanted in a 45-degree angle to reaching the dorso-anterior edge of the orbit. The nasals cover the olfactory capsules and curve ventrolateral to about half the diameter of the external nostril (they do not reach the maxillae) and then turn upward over and dorsally surrounding the nasal capsule. Dorsally, between the anterior tip of the nasals and between the anterior tip of the cartilaginous nasal capsule, a thin ossification of the septum nasi is visible between the nasals with its apex directed posteriorly. Parasphenoid. The large parasphenoid lacks ornamentation. The cultriform process is, Published as part of Osorno-Muñoz, Mariela, Gutiérrez-Lamus, Doris L., Lynch, John, Keeffe, Rachel, Caicedo-Portilla, José Rancés, Chan, Kin Nok, Tonini, João F. R. & De Sá, Rafael O., 2023, Three new species of the Synapturanus rabus complex (Microhylidae: Otophryninae) in Colombia with a review of the genus Synapturanus, pp. 151-196 in Zootaxa 5258 (2) on pages 157-175, DOI: 10.11646/zootaxa.5258.2.1, http://zenodo.org/record/7777048, {"references":["Pyburn, W. F. (1975) A new species of microhylid frog of the genus Synapturanus from southeastern Colombia. Herpetologica, 31, 439 - 443."]}

Synapturanus artifex sp. nov. Synapturanus sp. “ Amazonas ” Holotype (Fig. 6). SINCHI-A 6632 (SNC-H 405), adult male, collected at Departamento Amazonas, “area no municipalizada” La Chorrera, cabildo indígena Okaina, Comunidad de Puerto Oriente, Colombia (01°31′43.7″ S, 72°40′38.5″ W), 134 m., on October 18, 2019, by Marco Fidel Rochicón and Vitilio Iyokina. Paratopotypes. Adult female SINCHI-A 6469 (MOM 7430), adult males SINCHI-A 6631 (SNC-H 404), SINCHI-A 6633 (SNC-H 406), and SINCHI-A 6518 (MOM 7479); all collected along with the holotype by Zabdiel Anderson Ciake, Alfredo Iyokina, Sofonias Iyokina, Diomedes Vigidima, and Epifanio Ciake. Diagnosis: A species of Synapturanus diagnosed by the following combination of characters: 1) SVL small size, adult female SVL = 17.6 mm (n =1); adult males 15.2–15.9 mm (χ = 15.5 ± 0.1 mm, n = 4), 2) stout and body elongated, 3) head narrower than body, snout pointed in dorsal view, rounded in lateral view, and ventrally distinctly projecting beyond the edge of the anterior upper jaw, 4) symphysis of lower jaw with an unpigmented notch and external nares with a wide and unpigmented rim, 5) tympanum slightly visible, 6) vocal slits absent, 7) rounded choanae, about equal in diameter to the unpigmented edge of the external narin, 8) vomerine teeth absent, 9) hand formula III>IV>II>I, digits becoming thinner towards their distal ends, fingertips rounded or slightly pointed, fingers bordered by a thin fringe, interdigital membrane absent, 10) subarticular tubercles absent, thenar tubercle elongated, palmar tubercle rounded with undefined edges, 11) adult males with a protuberant and oval-shaped glandular area on the internal surface of distal forearm, extending from the wrist to the middle of the distal forearm and dorsally visible, 12) relative lengths of toes IV>III>V>II>I, toes are thin and subcylindrical with a distal rounded or lanceolate widening, with thin fringes extending from the base of the digits to their distal end, digits lack webbing, 13) inner metatarsal tubercle small and elongated, outer metatarsal tubercle absent, subarticular tubercles absent, unpigmented subarticular spots on toes, 14) knee, heel, and wrist with skin folds, 15) cephalic groove distinct, extending over the head and tympanum and reaching and extending beyond the lower jaw articulation and reaching or distinctly crossing over entire throat, 16) in life dorsal body surfaces dark brown, with or without pale dorsal spots, occipital groove area light brown, edge of tympanum with small orange spots, ventral area of flanks greyish, oblique light brown to orange stripe begins posterior to the eye and extends over the tympanum and broadening towards the arm, ventrally, 17) canthal stripe present or absent, if present poorly defined; canthal stripe formed by a series of small, and discontinuous cream spots, extending from the rostral tip and dorsal to the flank, 18) in life ventral surfaces dark brown on snout and on edges of throat and its anterior surface, lighter on the posterior half of the throat; chest with two triangular-shaped spots that do not meet medially, most of the belly surface translucent, lineae masculinae (Davis and Law, 1935) present, ventral surfaces of thigh light brown, the remaining of ventral leg surfaces dark brown, hands and feet dark brown, thenar and inner metatarsal tubercles, subarticular surfaces, and tip of digits unpigmented, 19) forearm gland cream-colored in preserved specimens. Synapturanus artifex sp. nov. can be differentiated from S. rabus (traits in parenthesis) in being somewhat smaller, SVL 17.6 mm in one female (vs. 17.2-19.0 mm) and SVL 15.2–15.9 mm in males (vs. 16.2-16.6 mm); two males have few and poorly defined pale spots on the back (absent in S. rabus), S. artifex sp. nov. lacks irregular markings on the posterior limbs (most specimens have irregular spots on one or both legs in S. rabus), gray flank, a light brown stripe runs obliquely posteroventral to the eye and broadening towards the arm (uniformly dark brown), entire belly, central area of chest, and proximal throat translucent gray, lacking brown pigmentation (only the central part of belly is translucent gray). Synapturanus artifex males are smaller than S. danta (SVL 15.2-15.9 vs. 17.6-17.9). Synapturanus artifex sp. nov. is smaller than S. latebrosus sp. nov. (traits in parenthesis) SVL 17.6 mm in one female (vs. 20.0-22.0 mm) and SVL 15.2-15.9 mm in males (vs. 18.1-19.0 mm). Synapturanus artifex sp. nov. has a longer tibia, 42% of SVL (vs. 37%), and also larger eyes than S. latebrosus sp. nov. judging by the ED/END ratio, 0.7 in average for both sexes (vs. 0.6). Synapturanus artifex sp. nov. has a broad, unpigmented midventral area that extends over the chest and throat, whereas in S. latebrosus sp. nov. it is narrow and circumscribed to the belly. In S. artifex sp. nov. the cephalic groove crosses over the entire throat whereas in S. latebrosus sp. nov. it slightly extends beyond the lower jaw. Synapturanus artifex sp. nov. differs from S. sacratus sp. nov. (traits in parenthesis) in being slightly larger, SVL 17.6 mm in one female (vs. 16.9, 17.3 mm in two females) and SVL 15.2 -15.9 mm in males (vs. 14.0, 15.0 mm in two males). Synapturanus artifex sp. nov. exhibits a poorly defined faint canthal line when present (vs. a conspicuous and continuous canthal stripe that becomes discontinuous over the body flanks); in life, S. artifex sp. nov. has a thick, light brown to orange stripe running obliquely over the tympanum toward the ventral arm (vs. not evident in S. sacratus sp. nov.); cephalic groove distinctly crosses over the entire throat (vs. cephalic groove slightly extends beyond the lower jaw). Synapturanus artifex sp. nov. with SVL 15.2-15.9 mm in males is clearly smaller than S. mirandariberoi (SVL 27.0– 31.7 mm in males), S. salseri, (SVL 23.7-26.4 mm in males), S. zombie (SVL 37.0- 40.6 mm in males), S. mesomorphus (SVL 22.9-26.0 mm in males), and S. ajuricaba (SVL 29.3-33.2 mmv in males). Synapturanus artifex sp. nov. lacks any pattern of speckles, spots or blotches on the back present to a greater or lesser extent in the above-mentioned species, although the holotype and another male of S. artifex sp. nov. shows few whitish spots of diffuse contours. In S. artifex sp. nov., the forearm gland is scattered and reaches up to the middle vs. protruding and concentrated towards the wrist in S. salseri. Description of Holotype. An adult male with a protruding and elongated glandular surface, broader near the wrist, on the inner distal forearm; the glandular area extends over the middle of the forearm and is dorsally visible; body smooth, ovoid in dorsal view, small (SVL = 15.5 mm); head triangular, almost as wide as long (HL = 4.2, HW = 4.1), snout tip acuminate, snout projects beyond the anterior edge of the upper jaw (SL/SW= 0.7); nostrils with a distinct light colored rim, directed laterally; the eye–nostril distance is slightly greater than the eye diameter (END = 1.5 mm, ED = 1.2 mm), canthus rostralis defined, loreal region concave below marked by a distinct groove that reaches from the antero–ventral edge of eye to the posteroventral edge of nostril, interorbital area concave, IOD = 2.2 mm, without occipital fold, a distinct shallow cephalic groove extending over the tympanum and barely exceeding the level of the lower jaw; tympanum visible, TD = 0.9 mm; vocal slits absent, tongue less wide than the oral cavity, tongue thin on posterior free edges; vomerine teeth absent; rounded choanae widely separated. Anterior and posterior limbs robust and short, hands without webbing, finger relative lengths III>IV>II>I, hand digits distally pointed, with narrow fringes on digits, subarticular tubercles absent, subarticular surfaces light colored, small and oval thenar tubercle located at the base of finger I, palmar tubercle rounded with poorly defined edges; distinct folds on knee and heel, less distinct on wrist and metatarsal area; toes lack webbing, toes subcylindrical and slightly expanded distally, distal tips lanceolate and flat in lateral view, except toe I that is distally pointed, toes with narrow fringes along their length, external edge of toe I reaches the ventral edge of the internal metatarsal tubercle; subarticular tubercles absent, inner metatarsal tubercle elongated, small, at the base of toe I; toes relative lengths IV>III>V>II>I; tibia length TBL = 6.7 mm, about 43% of snout–vent length. Live coloration. Dorsal body surfaces dark brown with few and poorly defined whitish spots, ventral flank gray, light brown band extends from behind the eye and broadening towards the arm, iris dark brown, dorsal articular surfaces and distal tips of fingers and toes unpigmented. Ventrolateral surfaces of throat dark brown distally as well as the snout, surfaces of hands and feet, forelimbs, tibia, and feet, light brown on medial and proximal areas of throat, as well as two separate patches on chest; edges of belly and thighs translucent gray, translucent, whitish central belly without brown pigmentation as in medial area of chest and over the fold between the throat and chest, lineae masculinea visible. Subarticular surfaces of fingers and toes unpigmented. Coloration of Preserved Specimens. Dorsally dark brown, with diffuse white to cream dots, ventral flanks and post-ocular band broadening towards the arm cream, the translucent ventral areas in life turn into light cream. Articular surfaces on fingers and toes cream. Measurements of Holotype (mm). SLV 15.5; HL 4.2; HW 4.1; HL/ESD 1.8; SL/SW 0.7, TD 0.9, ESD 2.3, END 1.5, ED 1.2, ED/END 0.8, TBL 6.7, IOD 2.2, TBL/SVL 0.4. Variation in the type series. Measurement data for the type series are given in Table 2 and Table S2. The canthal stripe is present in the female and two males; in the female SINCHI-A 6469 it is barely visible, discontinuous, and reaches the flank; in male SINCHI-A 6631 is distinct, discontinuous, and extends only to the area above the insertion of the forearm; in male SINCHI-A 6518 consists of dots over the posterior part of the canthus rostralis and over the eyelid, in male SINCHI-A 6633, as well as on the holotype, the canthal stripe is absent. The posterior surface of the throat can be translucent; the translucent belly can bear areas of small brown dots. Female SINCHI-A 6469 has two visible eggs (3.5 and 1.6 mm) at their longest side. Etymology. A Latin noun in aposition meaning artist, in allusion to the skills and extraordinary designs that Okaina, Uitoto, Bora, and Muinane indigenous peoples capture in their basketry in which they depict their life in nature. Distribution (Fig. 4). Synapturanus artifex sp. nov. is known only from the type locality. Tadpole (Fig. 7). During a sampling at Comunidad San Rafael del Caraparaná, “área no municipalizada El Encanto”, on April, 2022, one clutch, with two larvae was found in the soil, when removing the rootlets layer. The two larvae at stage 35 (Gosner 1960) have a total length of 11.9 and 10.4 mm, a body width of 4.2 mm and a tail length of 6.4 and 5.7 mm respectively. Each larva is embedded in a viscous and translucent jelly about 9.5 mm in diameter and the complete posture contained in its hole in the ground measures about 19 mm. The larvae were pinkish in life, cream in preservative, with fine brown marbling on the head and along the dorsal midline extending up to the tail proximally. No opercular folds are visible. The tail is oval in cross section, without fins, and it is 54% of the total length. Advertisement Call (Fig. 8). Calls of Synapturanus artifex sp. nov. were recorded from two individuals. The first individual recorded on October 19, 2019 at 20:00 hrs., air temperature of 26.9°C, and 91% relative humidity was not possible to collect with SINCHI-A 6631(https://doi.org/10.6084/m9.figshare.16943425). It was recorded from Puerto Oriente, at 134 m., “área no municipalizada” La Chorrera (1°31’43.7″S, 72°40’38.5″W), Departamento Amazonas, Colombia. The second individual corresponds to voucher SINCHI-A 7110 (Fig. 8), (https://doi. org/10.6084/m9.figshare.16943425) recorded on August 30, 2021 at 21:30 hrs., air temperature of 25.6°C, and 81% relative humidity recorded from Puerto Oriente, at 134 m., “área no municipalizada” La Chorrera (2°31′43.7″S, 72°39′53.6″W), Departamento Amazonas, Colombia (Table 3). The call of Synapturanus artifex sp. nov. (n = 3) consists of single (one pulsed note, Guild C sensu Emmrich et al.. 2020) tonal notes (mean note length 0.040, range 0.029 -0.052 seconds, SD=0.007) and interval between notes between 5.35 and 17.54 seconds (χ = 7.52), dominant frequency between 1639 and 2224 Hz (χ = 1904 Hz, SD=216.9). The calls have a descendent modulation frequency. Natural History. In 2019, specimens were collected in a secondary forest during nights with light rain; we found them by gently removing the thick layer of rootlets of the floor, below the leaf litter. In 2021, specimens were collected on a night with no rain, but after a heavy downpour in the afternoon. They were calling everywhere and the caller specimen SINCHI-A 7110 (Table 3) was collected in an “indigenous chagra” (traditional crop system), about half a hectare in size, with no trees to shade the ground in the daytime. According to the owner of the “chagra” this forest named “monte bravo” was cut down to make the settlement 40 years ago, this “chagra” area has been cut and burned several times, most recently a year ago. The male was singing in the root of a bush about 10 cm depth under the rootlets. In 2022, specimens were collected in a secondary forest which was used as a cattle breeding pasture in the 70’s. The adults were found under the rootlets, about 10 cm depth; in the same microhabitat where the adults were found, one postures with two larvae was collected in a small hollow in the soil., Published as part of Osorno-Muñoz, Mariela, Gutiérrez-Lamus, Doris L., Lynch, John, Keeffe, Rachel, Caicedo-Portilla, José Rancés, Chan, Kin Nok, Tonini, João F. R. & De Sá, Rafael O., 2023, Three new species of the Synapturanus rabus complex (Microhylidae: Otophryninae) in Colombia with a review of the genus Synapturanus, pp. 151-196 in Zootaxa 5258 (2) on pages 163-168, DOI: 10.11646/zootaxa.5258.2.1, http://zenodo.org/record/7777048, {"references":["Gosner, K. L. (1960) A simplified table for staging anuran embryos and larvae wit notes on identification. Herpetologica, 16, 183 - 190."]}