Tropidurus madeiramamore, Carvalho & Paredero & Villalobos-Chaves & Ferreira & Rodrigues & Curcio, 2024

Carvalho, André L. G., Paredero, Rafael C. B., Villalobos-Chaves, David, Ferreira, Elaine, Rodrigues, Miguel T. & Curcio, Felipe F., 2024, A highly polymorphic South American collared lizard (Tropiduridae: Tropidurus) reveals that open-dry refugia from South-western Amazonia staged allopatric speciation, Zoological Journal of the Linnean Society 201 (2), pp. 493-533 : 513-527

Tropidurus madeiramamore sp.nov.

( Figs. 2 , 9A–C , 10 , 11A, B )

LSID: https://zoobank.org/ urn:lsid:zoobank.org:pub:740FE136-CE17-4393-85F7-BEEC5CF2837E

Tropidurus torquatus hispidus – Cunha, 1961. Boletim do Museu Paraense Emílio Goeldi, Zoologia 39: 76 [part].

Tropidurus oreadicus – Rodrigues, 1987. Arquivos de Zoologia 31: 188 [part].

Tropidurus grupo torquatus sp. A – Nascimento et al., 1988. Boletim do Museu Paraense Emílio Goeldi, Zoologia 4: 32 [part].

Tropidurus oreadicus – Vitt, 1993. Canadian Journal of Zoology 71: 2371 [part].

Tropidurus oreadicus – Vitt & Caldwell, 1993. Journal of Herpetology 27: 51 [part].

Tropidurus oreadicus – Ávila-Pires, 1995. Zoologische Verhandelingen 299: 195 [part].

Tropidurus oreadicus – Ribeiro-Júnior, 2015. Zootaxa 3983: 30 [part].

Holotype: MZUSP 107155 , adult male from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 21.5″S, 63°04 ʹ 24.6″W; ~ 178 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 15 November 2017.

Allotype: MZUSP 107158 , adult female from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 22.5″S, 63°04 ʹ 23.6″W; ~ 167 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 15 November 2017.

Paratypes: MZUSP 107156 and 107157, adult females from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 22.9″S, 63°04 ʹ 24.2″W; ~ 170 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 15 November 2017 . MZUSP 107159 and 107160, adult females from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 21.4″S, 63°04 ʹ 24.5″W; ~ 162 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 . MZUSP 107161 , adult female from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 22.3″S, 63°04 ʹ 24.3″W; ~ 178 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 . MZUSP 107162 , adult female from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 21.8″S, 63°04 ʹ 24.1″W; ~ 178 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 . MZUSP 107163 , adult female from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 21.3″S, 63°04 ʹ 24.4″W; ~ 173 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 . MZUSP 107164 , adult female from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 22.0″S, 63°04 ʹ 24.0″W; ~ 176 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 . MZUSP 107165 , adult male from Floresta Nacional do Jamari , Município de Itapuã de Oeste, Estado de Rondônia, Brazil (09°12 ʹ 22.5″S, 63°04 ʹ 23.9″W; ~ 173 m a.s.l.), collected by A. L. G. Carvalho and R. C. B. Paredero on 16 November 2017 .

Common names: ‘Lagartixa preta’ (black lizard), ‘lagartixa’, ‘calango’, South American collared lizard.

Diagnosis: Tropidurus madeiramamore qualifies as a member of Tropidurus Wied, 1825 by having a series of morphological characters indicated by Frost et al. (2001) as exclusive to the genus: skull not highly elevated at the level of the orbits; presence of ‘flash’ marks on ventral surface of thighs; circumorbitals distinct from other small supraorbital scales; lateral fringe not developed on both sides of toe IV; enlarged middorsal scale row absent; and tail terete.

The new species fits the definition of the Tropidurus torquatus species group (sensu Frost et al. 2001) by lacking an enlarged middorsal scale row (well marked in species of the T. spinulosus group, more pronounced in males), by the black coloration of the ‘flash’ marks on the underside of the thighs and cloacal flap of adult males (yellow, cream, or orangey ‘flash’ marks occur in males of the T. spinulosus group), and by lacking a dorsoventrally flattenedbody (stronglyflattenedinspeciesofthe T.semitaeniatus group and, more moderately, in T. bogerti ).

Tropidurus madeiramamore is distinguished from other members of the T. torquatus species group by the following combination of traits: a single, extremely wide and deep mite pocket on the lateral neck; post-humeral (axillary) and prefemoral (inguinal) mite pockets absent; posterior ventral head and throat coloration black; venter dark pigmented (light in some females, rarely in males) and/or mottled chest, with a tendency towards melanism observed especially in males; black ‘flash’ marks on the precloacal flap, underside of thighs, ventral base of the tail, and area near the base of toe I (and non-rarely of finger I) in males; and saxicolous habit.

Comparisons: Tropidurus madeiramamore is distinguished from all its congeners in the T. torquatus species group but T. oreadicus in having mite pockets Type D (sensu Rodrigues 1987), characterized by the presence of a single granular mite pocket on the lateral neck and no post-humeral (axillary) or prefemoral (inguinal) mite pockets. However, the lateral neck mite pocket of T. madeiramamore ismuchwideranddeeperthanthatof T.oreadicus ( Fig. 2 ). The new species differs specifically from T. azurduyae , T. catalanensis , T. chromatops , T. cocorobensis , T. etheridgei , T. hygomi , T. imbituba , T. psammonastes , T. sertanejo , and T. torquatus in having one mite pocket on the lateral neck (these species have two, except T. sertanejo , which lacks lateral neck mite pockets). It also differs from T. catalanensis , T. erythrocephalus , T. hispidus , T. insulanus , T. imbituba , T. montanus , T. mucujensis , T. sertanejo , and T. torquatus in lacking post-humeral mite pockets (present in these species) and from T. catalanensis , T. erythrocephalus , T. imbituba , T. itambere , T. montanus , T. mucujensis , T. sertanejo , and T. torquatus in lacking prefemoral mite pockets (present and usually well marked in these species).

Tropidurus madeiramamore differs from all congeners in being the only highly chromatically polymorphic species of Tropidurus ( Fig. 5 ). The species usually has a dark-pigmented venter (light in some females, rarely in males) and/or mottled chest, tending to intense melanism, a unique condition in the genus. It also differs from all other congeners in the fact that most specimens exhibit a line (white or black) on the mid-flank, interrupted or continuous. Specimens of the T. torquatus – T. catalanensis – T. imbituba species complex may exhibit a dark longitudinal stripe on the flank (usually present in females) outlined by pale coloration or well-defined white lines, but such a stripe (when present) covers the whole upper flank, differing from the thin dark line observed on the mid-flank of T. madeiramamore . The new species is most similar in coloration to T. oreadicus but exhibits a grey or brownish grey dorsal background and orange tones embellishing the head, dorsum, and flanks in both sexes, whereas T. oreadicus ( Figs 9D–F , 11F , 12 ) has a light brown or greenish brown dorsum (populations with orangey specimens are rare; e.g. Formoso do Araguaia, Tocantins, Brazil). Tropidurus madeiramamore is distinguished from all species in the T. torquatus group in having large male specimens with black flash marks on the posteriormost portion of the tibial region towards the base of toe I (and sometimes also near the base of finger I). Regarding flash marks, it also differs from most congeners in that group (except T. itambere and T. psammonastes ) in having a black triangular flash mark on the ventral base of the tail, and from T. azurduyae , T. catalanensis , T. chromatops , T. cocorobenis , T. etheridgei , T. imbituba , T. itambere , and T. torquatus in lacking a midventral ‘flash’ mark (in some of these species, the midventral flash mark is present only in large adult males).

Tropidurus madeiramamore is a medium-sized lizard (SVL: 67.59–103.84 mm in males and 61.31–82.39 mm in females) that broadly overlaps most species in the T. torquatus species group in size ( Carvalho et al. 2016, 2018) but T. hygomi (SVL: 54.15–67.30 mm in males and 60.27–65.37 mm in females), T. cocorobensis (SVL: 54.15–67.30 mm in males and 60.27–65.37 mm in females), and T. itambere (SVL: 62.28–84.77 mm in males and 58.88–77.43 mm in females). In terms of ecology, the saxicolous habit distinguishes T. madeiramamore from T. cocorobensis , T. hygomi , and T. psammonastes , which are strictly psammophilous.

Description of holotype (MZUSP 107155; Figs 2 , 9A–C , 10 , 11A, B ): Medium-sized male specimen of Tropidurus, SVL 96.25 mm; head subtriangular, length 28% of SVL and width 72% of head length; skull not compressed, not strongly elevated at level of orbits; snout rounded in dorsal view, rostrum not noticeably shortened relative to most other species in the genus; scales of frontonasal region tumescent, not imbricating posteriorly; lenticulate scale organs distributed on the head, more abundant on the rostral, frontonasal, supraocular, lorilabial, and labial areas; rostral tall, approximately three times (in lateral view) as high as first supralabial, contacting first supralabials, first lorilabials, nasals, and postrostrals; 2/1 postrostrals; nasal single, protruding, pentagonal, elongated anteroposteriorly, with the tip of the pentagon directed anteriorly, in contact with rostral, 1/1 post-rostral, anteriormost canthal, and 5/5 smaller scales separating it posteriorly from larger scales of the frontonasal area; nostril elliptical, occupying ~20–25% of nasal area, positioned posteriorly, directed dorsolaterally; 3/3 canthals, anteriormost separated from supralabials by 1/1 row of lorilabials, third one not in contact with anteriormost superciliary and anteriormost preocular; 9/8 laminate superciliary scales weakly produced vertically; 1/1 row of short semilaminate scales separating superciliaries from palpebrals; palpebrals subgranular, central ones forming the upper eyelid pigmented, lower eyelid poorly pigmented, semi-translucent; first row of palpebrals larger, squarish; scales of second row of palpebrals smaller than those on the first row, subconical, tumescent, 1–3 (usually 1–2) scale organs on tip; pupil circular; 4/4 main rows of supraoculars, the enlarged medial ones occupying less than half the width of the supraocular area; 1/1 irregular row of elongate, angulate circumorbitals; 1/1 row of short semilaminate scales separating circumorbitals from superciliaries; interparietal enlarged, subcordiform, ~1.3× longer than wide, anterior and posterior margins indented; parietal eye distinct, medially positioned right after the posterior limit of the first one-third of the interparietal scale; 1/1 preocular, about one-quarter the size of subocular, dorsally keeled, in contact with 4/3 loreals and 1/1 supernumerary scale separating it from posteriormost canthal; 1/1 suboculars, elongate, dorsally keeled, separated from supralabials by 2/1 row of lorilabials posteriorly; 3/2 rows of loreals, first row with four scales and second with two scales on both sides, third row with single scale on left side, absent on right side; 2/2 rows of lorilabials, first row with 8/8 scales and second row with 4/5 scales; 5/5 enlarged supralabials, followed by 6/5 smaller scales reaching the rictus oris; temporals slightly imbricate, keeled, slightly mucronate, wider than longer, at least three times larger than lateral neck scales and smaller than dorsals and parietals, lower temporals slightly smaller than upper temporals; four short rows of occipitals right after interparietal, subconic in shape, much smaller than parietals; ear shaped like an inverted keyhole, ~ 6.3 mm × 2.5 mm, canal deep; tympanum translucent; preauricular fringe consisting of a row of 7/9 smooth, sublanceolate scales, much shorter than half the ear opening width, about the same size as upper temporals; mental extending posteriorly to the level of the first one-third of the first adjacent infralabials; 4/4 angulate, enlarged postmentals, first pair of postmentals not in contact with one another, 1/1 postmentals in contact with first infralabial; 5/5 enlarged infralabials followed by 3/3 smaller scales reaching the rictus oris; 7/8 sublabials; 46 gular scales, smooth, non-mucronate, longer than wide anteriorly, wider than long posteriorly, becoming imbricated posteriorly.

Vertebral crest absent; 88 dorsals, keeled, mucronate, wider than long; keels on dorsal and caudal scales align to form continuous, longitudinal, slightly oblique lines observable macroscopically; scales on the lateral neck keeled, mucronate, at least three times smaller than dorsals; post-humeral region with small, subgranular, smooth, non-mucronate scales, increasing in size, intensity of keels, and mucronation towards the flanks; 86 scale rows around midbody; 83 ventrals, smooth, non-mucronate, imbricate, about half the size of the largest dorsals; 17 cloacal scales; dark-pigmented ‘flash’ marks present on the ventral surface of thighs, precloacal flap, ventral base of tail, and distalmost, ventral portion the tibial region and base of feet towards base of toe I, absent in the midventer; femoral ‘flash’ marks formed by a patch of 6/6 rows of dark glandular scales; precloacal ‘flash’ marks formed by 12 rows of dark glandular scales, and that on the base of the tail by nine rows of dark, glandular scales organized in a triangular shape (base of triangle facing the cloacal slit); supracarpal scales smooth, non-mucronate, subrhomboidal in shape; supratarsals mostly smooth, non-mucronate, rhomboidal or subrhomboidal in shape, slightly keeled and mucronate towards base of toe IV; one or two (usually one) scale organ positioned on the distal end of supracarpals and supratarsals; proximal infracarpals and infratarsals mostly smooth (those reaching the base of fingers slightly keeled and mucronate), rhomboidal or subrhomboidal in shape; scales covering the anterior portion of palm of hand and sole of foot tumescent, apparently glandular, with strong signs of abrasion; fingers and toes thin, cylindrical, compressed laterally, fingers III and IV of left hand amputated; supradigital lamellae smooth, rhomboidal, scale organ positioned on the distal end of the scales; infradigital lamellae tricarinate and mucronate, –/15 under finger IV + ungual, 23/25 under toe IV + ungual, medial careen larger and more projected than laterals; claws long, curved, brown in colour; scales of forearm keeled and strongly mucronate anteriorly and dorsally, grading to smooth scales with no or short mucrons and smaller size posteriorly and ventrally; scales on preaxial axis of thigh smooth, with sensorial organ on tip of scale, grading into keeled and mucronate dorsally, and strongly keeled and mucronate posteriorly, scales on posterior axis smaller than anterior and dorsal thigh; 24/25 tibial scales, keeled, mucronate, more intensely keeled and mucronate distally; rictal and postauricular folds present; nuchal, supra-auricular, and dorsolateral folds absent; oblique neck fold well marked, defining a single lateral neck mite pocket on each side of the neck, extremely broad and deep, starting above the level of the dorsal margin of ear-opening and reaching the head venter, coated with granular, unpigmented scales, internal folds not forming full subcompartments; antegular fold present, gular fold incomplete medially; antehumeral fold present and well marked, covered with imbricate scales similar to or smaller than those on lateral neck; post-humeral (axillary) and prefemoral (inguinal) mite pockets absent; tail slightly compressed laterally, broken; caudal verticils absent; scales of tail imbricate, keeled, mucronate, anterior ones 2.5× larger than dorsals or more, progressively reducing in size towards the tip; ventral caudal scales smooth, poorly mucronate or non-mucronate.

Coloration in life ( Fig. 11A, B ): Dorsal body with an overall brindled pattern and extremely subtle orangey tone towards the anterior flanks; snout and dorsal head dark brown, with sparse light tan spots, smaller than one scale in size; first two rows of (enlarged) palpebral scales, labial, lorilabial, and loreal areas with touches of cream, bluish grey, and sparse light tan spots; nape and lateral neck background with light tan and brownish tones conspicuously lighter than dorsal head and body background, ornamented with irregular black spots, some of which are connected, forming short, irregular, anteroposterior, oblique stripes on the lateral neck; black nuchal collar well marked, slightly oblique, two to five scales wide, starting immediately before the insertion of forelimbs, dorsally incomplete, dorsal limit attaining paravertebral region, outlined by light tan contour nearly half the width of nuchal collar; background of dorsal body and flanks dark brown, sprinkled with small, irregular black spots of variable sizes; paired series (one on each side of the body) of ~12 irregular paravertebral black blotches from nape to base of tail, distinctly larger (6–11 scales in size) than small black spots scattered on dorsum, clearly visible from nape to post-scapular level, barely distinct from background posteriorly; dorsum ornate, with a series of eight wavy rows of light tan spots, one to four scales in size, from side to side of the body; fore- and hindlimbs with background similar to dorsum, marked with irregular black spots of variable sizes; forelimbs ornate, with thin (one scale wide), transverse, light tan streaks (five discernible along the right arm and forearm, and one on the left forearm, near the wrist) combined with randomly distributed light tan spots, one to four scales in size; hindlimbs without transverse streaks, light tan spots present but inconspicuous; hand, feet, fingers, and toes with overall coloration similar to limbs but less conspicuous; fingers and toes transversely crossed by thin, light tan bands; dorsum of tail light brown, with irregular black pigmentation concentrated anteriorly, sparse towards the end; flanks of tail light brown, small bluish grey area noticeable at the base, more evident immediately after insertion of thighs. Ventral surface of head with touches of cream and bluish grey anteriorly, mottled with a dark reticulum delineating cream blotches medially and towards the chin, cream markings progressively assuming rounded shape towards the posterior part of chin; coloration changes abruptly to solid black on the posterior ventral portion of the head, followed by similar fully melanic throat, neck, chest, venter, and underside of limbs; palm of hands and sole of feet cream; black patches of α-gland scales on the underside of thighs, precloacal flap, and ventral base of feet charcoal in colour, discernible even against the melanic background; ventral surface of tail light greyish cream, except for the area immediately posterior to the vent, marked by a triangular patch of α-gland scales charcoal in colour.

Coloration in preservative ( Figs 9A–C , 10 ): Overall coloration pattern of head and body preserved; subtle orangey tone originally discernible on the dorsal head and towards the anterior flanks lost; brown dorsal coloration became a little darker, making the light tan coloration on the nape and lateral neck proportionally lighter; cream and bluish grey tones on the first two rows of (enlarged) palpebral scales, labial, lorilabial, and loreal areas turned pale cream; black coloration of nuchal collar preserved, outline turned pale cream; background of dorsum and flanks dark brown, irregular black spots spread all over preserved; series of wavy rows of light tan spots reaching from side to side of the body turned pale cream; light tan streaks and spots on fore- and hindlimbs became pale cream, resulting in increased contrast against the dark brown background coloration; same observed for coloration of hands, feet, fingers, and toes; background coloration of the dorsum and flanks of tail became lighter brown, making the dark pigmentation seen anteriorly more conspicuous, small bluish grey area at the base of tail, immediately after insertion of thighs, nearly unaltered; touches of cream and bluish grey anteriorly on ventral head turned pale cream; dark reticulum delineating cream blotches medially and towards the chin became more evident; solid black coloration on the posterior ventral head, throat, neck, chest, venter, and underside of limbs became slightly lighter, developing a dark brownish appearance; palm of hands and sole of feet cream, unchanged; all patches of charcoal α-gland scales on ventral body became slightly lighter; original light greyish cream ventral surface of tail lost the greyish tone and turned cream.

Measurements of holotype (in millimetres): AGD, 50.84; AL, 15.96; BH, 20.52; EOS, 23.61; FAL, 14.55; FOL, 26.91; HDL, 16.56; HH, 12.95; HL, 26.60; HW, 19.20; MB, 31.82; SL, 18.59; SVL, 96.25; THL, 20.96.

Taxonomic remarks: Despite the chromatic polymorphism and body size variation identified by Vanzolini (1986), and subsequently described by Vitt (1993) and Vitt and Caldwell (1993), as potential evidence of multiple Tropidurus species associated with the savannah enclaves of the state of Rondônia, Rodrigues (1987) chose to allocate those populations under the name T. oreadicus Rodrigues, 1987 . In contrast to these studies, our results support a single polymorphic species associated with the savannah enclaves from Rondônia, which differs remarkably in most morphological parameters from T. oreadicus , except for the presence of a single mite pocket on the lateral neck (Type D, sensu Rodrigues 1987). Thus, we assign all Tropidurus populations distributed in the state of Rondônia confidently to T. madeiramamore , including those treated by Cunha (1961), Rodrigues (1987), Nascimento et al. (1988), Vitt (1993), Vitt and Caldwell (1993), and Ávila-Pires (1995), and some of the populations listed by Ribeiro-Júnior (2015). This latter author informed on the occurrence of ‘ T. oreadicus ’ in five localities in the state of Amazonas and one in the state of Acre, both in northern Brazil ( Fig. 13 ). Our sampling does not include specimens from those areas; nonetheless, given the large geographical gap with respect to the closest confirmed occurrence records of T. oreadicus in the core Brazilian Cerrado (~ 870 km in a straight line), the assignment of the specimens reported by Ribeiro-Júnior (2015) from Amazonas and Acre to T. oreadicus seems unlikely. It is possible that the reported specimens from the Parque Estadual do Guariba, in Novo Aripuanã, and from the vicinities of Rio dos Marmelos, in Manicoré, are assignable to T. madeiramamore ; however, the corresponding voucher material requires revision. The identification of samples from Puruzinho and Lábrea, located to the west of the Madeira River, is more doubtful, as is the record from Porto Acre ( Fig. 13 ). These records might be inaccurate or in error, given that, to our knowledge, the region lacks rocky outcrops.

Etymology: The specific epithet that makes up the name Tropidurus madeiramamore is an indeclinable word formed by the juxtaposition of the proper nouns Madeira (Portuguese language) and Mamoré (Tupi-Guarani language). These are the names of the Amazonian rivers that appear to circumscribe the northern and western distribution limits of the species in the State of Rondônia, Brazil. Madeira-Mamoré is also the name of the world-famous railroad built between 1907 and 1912 to export rubber and other goods produced in the western Brazilian and Bolivian Amazonia ( Bennitt 1913). During the field expedition carried out in November 2017, A.L.G.C. and R.C.B.P. followed part of the historical path of the ‘Madeira-Mamoré Railway’ searching for lizards, among other areas in the state of Rondônia. This was the most important terrestrial connection between the Brazilian territories of Porto Velho and Guajará-Mirim until 1966, when the Madeira-Mamoré Railway was officially shut down, after 54 years of service. During the field trip, A.L.G.C. and R.C.B.P. witnessed intense environmental degradation in the region, fuelled synergistically by population growth, logging, mining, farming, and ranching ( Pedlowski et al. 2005). Conservation issues in the area have been aggravated by the recent development of some of the largest hydroelectric dams and power plants ever built in the Brazilian Amazonia (2008–2016), namely Santo Antônio and Jirau ( Fearnside 2014). By naming T. madeiramamore after two of the most magnificent rivers of Western Amazonia, we aim to call attention to the critical conservation threats currently faced by the areas drained by these rivers and their tributaries. These areas include the highly vulnerable cerrado enclaves that harbour populations of the new species.

Distribution and endemism: Tropidurus madeiramamore is spread over a large portion of the State of Rondônia, Brazil, but mostly restricted to small and historically isolated savannah (cerrado) enclaves surrounded by the Amazon forest (or currently deforested areas) ( Fig. 13 ). Together, our fieldwork, museum work, and literature analysis has expanded the previously known distribution of T. madeiramamore ( Vanzolini 1986, Vitt 1993, Vitt and Caldwell 1993) to ≥ 34 areas in 11 municipalities of the State of Rondônia. For instance, the species is currently known from sites in the Parque Nacional Serra da Cutia, Guajará-Mirim; Parque Natural Municipal Serra dos Parecis, Guajará-Mirim; Jaci-Paraná, Porto Velho; campus of the Universidade Federal de Rondônia – UNIR, Porto Velho; south margin of the Madeira River, near the Museu da Estrada de Ferro Madeira-Mamoré, Porto Velho; Floresta Nacional Jamari and neighbouring rock outcrops along the highway BR-364, Itapuã do Oeste; and also from cerrado enclaves in the municipalities of Alto Paraíso, Ariquemes, Cacaulândia, Cacoal, Candeias do Jamari, Costa Marques, Jaru, and Rio Crespo. Tropidurus madeiramamore is likely to be present in other enclaves located between these areas. For instance, in the early 1990s, A.L.G.C. observed the species in the backyard of a house in the neighbourhood Casa Preta, in Ji-Paraná (10°52 ʹ 19.6428″S, 61°57 ʹ 04.6224″W; ~ 154 m a.s.l.), a municipality located halfway between Jaru and Cacoal. During the expedition carried out in November 2017, A.L.G.C. and R.C.B.P. visited Ji-Paraná but failed to locate T. madeiramamore in the searched areas, possibly owing to the expanded urban development that eliminated the natural habitats used by the species.

Since the early 1960s, the Amazon forest of the State of Rondônia has been largely destroyed, especially after the expansion of highway BR-364 to connect the municipalities of Vilhena, in the eastern limit of the state, to Porto Velho, in its north-western part ( Fearnside and Ferreira 1984, Piontekowski et al. 2019), and implementation of colonization projects and settlements by the Instituto Nacional de Colonização e Reforma Agrária (INCRA) ( Fearnside 1986). Together with the Amazon rainforest, savannah enclaves along highway BR-364 were wiped out or exposed after removal of the surrounding forest matrix and subsequent conversion of the original landscapes into pastures for cattle, agricultural fields, mining sites, or urban areas. Today, the last patches of natural habitats are mostly restricted to a few conservation units and indigenous territories ( Pedlowski et al. 2005). In these areas, enclaves of variable sizes that potentially harbour populations of T. madeiramamore are inaccessible by land. Examples of such areas are found in the Parque Nacional da Serra da Cutia and Indigenous Territory Uru-Eu-Wau-Wau, which contains the Parque Nacional de Pacaás Novos. These are some of the last continuous preserved areas in the heart of the State of Rondônia. During an expedition carried out by M.T.R. to the Parque Nacional de Pacaás Novos in April 2013, a few individuals of Tropidurus were observed at 911 m a.s.l., on a cliff at the Pico do Tracoá (10°50 ʹ 35.5128″S, 63°37 ʹ 41.7266″W), located at the easternmost limit of the park, in the municipality of Campo Novo de Rondônia. This record of T. madeiramamore corresponds to the highest elevation where the species has been registered to date.

The management plan of the Parque Estadual da Serra dos Reis provides information on the occurrence of ‘ Tropidurus hispidus ’ (SEDAM—RO 2019). However, the photograph of a sampled specimen included in the document (p. 197) shows that the species has been misidentified. Tropidurus hispidus is associated with open landscapes in Brazil, French Guiana, Guyana, Suriname, Venezuela, and part of the Brazil – Colombia border (Carvalho 2013). In Brazil, it occupies the domains of the semi-arid Caatinga and the Espinhaço mountain range, with additional records in transitional areas towards the Cerrado and in coastal sand dunes and restingas ( Rodrigues 1987, Carvalho 2013). Because the management plan lacked information on voucher material, we were unable to revise the specimen sampled at Serra dos Reis. However, the photograph included in the management plan (their fig. 139) sufficed to confirm that the ‘lagartixa preta’ (black lizard) registered in that state park corresponds to T. madeiramamore . The Reserva Biológica do Guaporé and Parque Estadual de Corumbiara, located at the extreme south of Rondônia, at the border with Bolivia, and ~50 and ~ 200 km to the south-east of Serra dos Reis (in a straight line), respectively, are additional areas where T. madeiramamore might occur. However, to our knowledge, comprehensive herpetological surveys have not been carried out in the southern portion of the State of Rondônia, resulting in very little information being available on the lizards present in the area.

In summary, the confirmed distribution of T. madeiramamore is limited to the central, north-western, and western portions of the State of Rondônia. Its occurrence in the extreme north of the state (to the east of Porto Velho and Itapuã do Oeste) is uncertain because most collection records are restricted to the margins of highway BR-364. In turn, the inventories carried out by Gainsbury and Colli (2003) recorded T. madeiramamore (their Tropidurus sp. ) in Guajará-Mirim but not in Pimenta Bueno and Vilhena, located in the southern portion of the State of Rondônia. Given that the sampling efforts reported in that study were substantial, we tend to believe that the species does not reach areas to the south-east of the collection site visited by A.L.G.C. and R.C.B.P. in Cacoal. Nevertheless, the geographical, ecological, and historical factors limiting the eastern-, southern-, and south-easternmost distribution of the species remain to be verified. At this point, as the specific epithet madeiramamore indicates, the Madeira and Mamoré rivers are assumed to limit the north-western and western distribution of T. madeiramamore , respectively. Interestingly, although these massive rivers have been thought to act as effective geographical barriers for a number of animal groups, this idea was found to be inappropriate for> 99% of the 1952 species analysed by Santorelli et al. (2018), at least in the case of the Madeira river. Nevertheless, Peixoto et al. (2020) did find evidence that lizard assemblages in South-western Amazonia are structured by the upper Madeira River, with 29.62% of the 27 species sampled in that study being isolated historically at one of the river banks. The known distribution of T. madeiramamore seems to reinforce these findings. However, for us to ascertain this, the unverified records of Tropidurus to the west of the Madeira river by Ribeiro-Júnior (2015) must be confirmed (see ‘Taxonomic remarks’; Fig. 13 ). Given that Tropidurus populations morphologically similar to T. madeiramamore have never been reported to the Bolivian Amazonia (e.g. Parker and Bailey 1991, Parker et al. 1993, Killeen and Schulenberg 1998, Chernoff and Willink 1999, Dirksen and De la Riva 1999, Montambault 2002, Carvalho et al. 2018), the species is recognized herein as endemic to Brazil, and more specifically, endemic to savannah enclaves of the state of Rondônia. Natural history and conservation: Tropidurus madeiramamore is not sympatric with any congener. Rather, Vitt (1993) reports on it coexisting with eight other lizard species in savannah enclaves from Rondônia, namely Ameiva ameiva (Linnaeus, 1758) , Anolis ortoni Cope, 1898 , Hoplocercus spinosus Fitzinger, 1843 , Cnemidophorus leminiscatus (Linnaeus, 1758) , Kentropyx calcarata Spix, 1825 , Uranoscodon superciliosus (Linnaeus, 1758) , Iguana iguana (Linnaeus, 1758) , and Copeoglossum nigropunctatum (Spix, 1825) . During fieldwork carried out in 2017, A.L.G.C. and R.C.B.P. observed Cnemidophorus cryptus Cole & Dessauer, 1993 , Tupinambis gr. teguixin (sensu Murphy et al. 2016) , A. ameiva , and I. iguana in syntopy with T. madeiramamore in Guajará-Mirim (former three) and Porto Velho (last species), but there were no field observations of interactions among them. Most lizards registered by Vitt (1993) and observed by A.L.G.C. and R.C.B.P. are widespread in Amazonia ( Ribeiro-Júnior 2015; Ribeiro-Júnior and Amaral 2016). Hoplocercus spinosus is the only one besides T. madeiramamore that is a typical Cerrado lizard; however, this species dwells in sandy sites within the savannah enclaves, whereas T. madeiramamore uses granitic outcrops (Vitt 1993, Vitt and Caldwell 1993).

Tropidurus madeiramamore expends most of its time on the rocks, performing territorial defence, thermoregulation, foraging, and reproductive activities, in addition to using crevices and the spaces underneath boulders as shelters and escape routes. As noted by Vanzolini (1986) and Vitt (1993), and confirmed by our field observations, even when approached by a potential predator, T. madeiramamore never enters the forest surrounding the enclaves. Adult males form harems and fiercely defend their territories from other males; these are visited by females and juveniles, which show submissive behaviours. When a dominant male approaches a female, it arches the body, and the female lifts the tail, exposing its orangey ventral surface. The same behaviour is displayed by other species of the T. torquatus species group (e.g. Carpenter 1977). Tropidurus madeiramamore can lay one to five eggs and are reproductive all year round (Vitt 1993). Most females collected in all nine localities sampled in November 2017 were gravid, indicating that reproduction is synchronic among populations. The diet of T. madeiramamore is composed mainly of ants and termites; however, specimens also feed on plant material, such as flowers (Vitt 1993, Gainsbury and Colli 2003). Vitt (1993) suggested that the ingestion of plants in this species is not accidental, given that some lizards had only this food item in the stomach, with no evidence of insect fragments.

Populations of T. madeiramamore are susceptible to the impacts of economic activities that have grown rapidly in Rondônia, including mining, hydroelectric production in large power plants, industrial farming, and illegal logging ( Fearnside 2014, 2017, Piontekowski et al. 2019). For instance, mining greatly affected the habitat used by the species in at least two localities sampled in 2017, the Floresta Nacional do Jamari (type locality) and Jaci-Paraná. Mining pits are expected to have strong detrimental effects on populations of T. madeiramamore because the species is strictly rupicolous. However, assessments of population size and population size fluctuation over time have not been published, even for populations located within conservation units (e.g. Floresta Nacional do Jamari and Parque Estadual Serra dos Reis). Deforestation ( Fearnside and Salati 1985, Fearnside 2017) and expansion of the paved road network in Rondônia ( Fearnside and Ferreira 1984) are expected to contribute synergistically to form open corridors capable of reconnecting lizard populations from otherwise isolated savannah enclaves. No studies have been performed thus far to evaluate the dispersion potential of T. madeiramamore through paved roads and other human-modified environments, although concrete-rich habitats are known to provide suitable thermal conditions that facilitate lizard colonization ( Hulbert et al. 2020, Mitchell et al. 2021), including Tropidurus ( de Andrade 2019) . All we know at this point is that populations of T. madeiramamore are established in a few urban sites in the municipality of Porto Velho (e.g. UNIR and EFMM) and at least one other in the municipality Itapuã do Oeste.

In summary, although natural habitats in the state of Rondônia have been reduced extensively over the years, and simulations have shown that 32–47% of the native forest of the State of Rondônia could be fully deforested by 2050 (Piontkowski et al. 2019), an evaluation of the degree of threat currently faced by T. madeiramamore is hindered by the limited biological information available for most populations throughout its range. An informed conservation assessment would require the estimation of parameters such as population size, number of mature individuals, gestation length, population decline over time, degree of fragmentation of the populations, and distribution range ( IUCN 2022). Given that this information is currently missing, we have no option but to recommend T. madeiramamore be classified as ‘Data Deficient’, following IUCN rules. Nonetheless, it is impossible to stress enough that the accelerated rates of habitat loss registered in Rondônia make an informed conservation assessment of T. madeiramamore absolutely critical.

Figures

Figure 2. Phylogenetic tree of Tropiduridae based on nuclear plus mitochondrial data combined, showing the distant relationship between the Tropidurus from savannah enclaves from Rondônia (Tropidurus madeiramamore) and Tropidurus oreadicus. Non-parametric bootstrap values (1000 replicates) are shown associated with branches.Dashed lines indicate branches whose lengths were altered for graphical purposes. In the lower left section of the figure, the lateral heads of the holotypes of T. madeiramamore (live specimen, MZUSP 107155) and T.oreadicus (preserved specimen, MZUSP 9465) are shown to illustrate the discrepancy in size between their lateral neck mite pockets. This diagnostic character distinguishes the species unambiguously.Scale bar: 1 cm.

Figure 5. Illustration of the chromatic polymorphism and frequency of the five flank (F1–F5) and ventral body (V1–V5) morphs identified across populations of Tropidurus from savannah enclaves from Rondônia (Tropidurus madeiramamore). Each shade indicates a different chromatic morph, and each chart represents a different locality, with values for males (top) and females (bottom) shown separately.See Figure 1 for details on the geographical location and characteristics of each site: (1) Cacoal; (2) Santa Cruz da Serra; (3) Ariquemes; (4) Itapuã do Oeste; (5) FLONA Jamari; (6) EFMM; (7) UNIR; (8) Jaci-Paraná; and (9) Guajará-Mirim.

Figure 9. Dorsal head, lateral head, and ventral head of the preserved holotypes of Tropidurus madeiramamore (adult male, MZUSP 107155; A–C) and Tropidurus oreadicus (MZUSP 9465; D–F). Scale bar: 1 cm.

Figure 10. Preserved holotype of Tropidurus madeiramamore(adult male, MZUSP 107155). A, dorsal body. B, lateral body. C, ventral body. Scale bar: 1 cm.

Figure 11. Tropidurus madeiramamore and Tropidurus oreadicus in life.A, B, general and ventral views of the holotype of T. madeiramamore (MZUSP 107155). C, D, general and ventral views of the allotype of T. madeiramamore (MZUSP 107158). E, juvenile of T.madeiramamore (MZUSP 107267) from the margin of the Madeira River near the Museu da Estrada de Ferro Madeira-Mamoré (EFMM), Porto Velho. F, general view of a topotype of T. oreadicus (MTR 33325) from Primeira Cachoeira do Rio Urucuia, Buritis, Minas Gerais, Brazil (16°05ʹ49.3080″S, 46°14ʹ57.9840″W). Photograph F is by courtesy of M. A. Sena.

Figure 13. Distribution of Tropidurus madeiramamore and Tropidurus oreadicus. Top map shows the fully allopatric range of the species. Tropidurus oreadicus is a typical Cerrado endemic, with distribution advancing northwards through the Tocantins River Basin.Bottom map is a blown-up view of the area delimited by the dashed rectangle in the top map. It shows the distribution of T. madeiramamore in savannah enclaves of the state of Rondônia, in addition to unconfirmed records of this species in the states of Amazonas and Acre (indicated by numbers 1–6), originally published by Ribeiro-Júnior (2015) as pertaining to ‘T. oreadicus’. Locality names:(1) Parque Estadual do Guariba, Novo Aripuanã, Amazonas; (2) Arredores da Fazenda Passo Formoso, Manicoré, região do Rio dos Marmelos, Amazonas; (3) Rodovia do Estanho, região do Rio dos Marmelos, Manicoré, Amazonas, Brazil; (4) BR-319 km 620, Puruzinho, Amazonas; (5) Lábrea, Amazonas, Brazil; and (6) Porto Acre, Acre.Refer to the Supporting Information (File S18) for a full list of geographical coordinates associated with the distribution records shown in the maps.

Figure12. Preserved holotype of Tropidurus oreadicus (adult male, MZUSP 9465). A, dorsal body.B, lateral body.C, ventral body.Scale bar:1 cm.