Brachycephalus tabuleiro, Mângia & Santana & de Oliveira Drummond & Sabagh & Ugioni & Costa & Wachlevski, 2023

Mangia, Sarah, Santana, Diego Jose, de Oliveira Drummond, Leandro, Sabagh, Leandro Talione, Ugioni, Luiz, Costa, Paulo Nogueira & Wachlevski, Milena, 2023, A new species of Brachycephalus (Anura: Brachycephali-dae) from Serra do Tabuleiro, Southern Brazil, Vertebrate Zoology 73, pp. 575-597 : 575

Brachycephalus tabuleiro sp. nov.

Figs 1 , 2 , 3 , 4 , 5 , 6

Holotype.

MNRJ 93859, adult male, collected at Serra do Tabuleiro, São Bonifácio municipality, Santa Catarina state, Brazil (27°53 ’58” S, 48°53 ’5” W, 915 m.a.s.l.; datum = WGS84), on 12 November 2015, by L.O. Drummond, L.T. Sabagh, and L. Ugioni.

Paratypes.

MHNCI 11498 (adult male), and UNIFESSPA 113 (adult female) collected with the holotype, CFBH 45453, CHSA.A 1403, MNRJ 93854-55, UNIFESSPA 112, ZUFMS-AMP14532 (adult males), CHSA.A 1404, and MHNCI 11499 (adult females) collected at the type locality, on 7 January 2018, by L. Ugioni, M. Wachlevski, B. Cesário, and D.C. Passos.

Non-type material.

ZUFMS-AMP14531, MNRJ 93856-58 and, CFBH 45452 (adults not sexed) collected at the type locality, on 7 January 2018, by L. Ugioni, M. Wachlevski, B. Cesário, and D. C. Passos.

Diagnosis.

Brachycephalus tabuleiro is a new species of the B. pernix group and can be distinguished from its congeners using the following combination of characters: (1) “bufoniform” body; (2) small adult SVL: 9.57-11.10 mm for males (n = 6), 10.88-12.70 mm for females (n = 3); (3) head proportionally small (HL/SVL 19-28%) and eye proportionally large (ED/HL 36-56%); (4) dorsum texture rough; (5) snout shape rounded in dorsal and lateral views; (6) general dorsal body color olive green with head, arms and legs yellow-orangish scattered with olive green, and an orangish vertebral stripe spotted with white and brown colors; (7) background yellow-orangish in the ventral region with reticulated green stains, mainly concentrated in the peripheral portion; (8) fingers I and IV greatly reduced, represented externally by a small lump, finger II reduced but distinct, and finger III larger and robust; (9) tips of the fingers I, II, and III rounded; (10) toes I and V present but externally indistinguishable, toe II greatly reduced, toe III short and distinct, and toe IV larger and robust; (11) tips of the toes II, III, and IV rounded; (12) skull and skeleton without hyperossification; (13) frontoparietal and sphenethmoid not fused; (14) premaxillary odontoids presents; (15) relative lengths of the transverse processes in descending order: III> IV> V> II> VI> VII>VIII; (16) radius and ulna fused, (17) phalangeal formula of fingers 1-2-3-1; (18) phalangeal formula of toes 0-2-3-4-0; (19) advertisement with one or two high-frequency notes (6115.4-6562.5 Hz), and 2-4 pulses per note.

Comparisons.

Characteristics of compared species are presented in parentheses. The new species presents a “bufoniform” body - term defined by Miranda-Ribeiro (1920) - and yellow-orangish coloration, which distinguished it from B. didactylus , B. hermogenesi , B. pulex , B. puri , and B. sulfuratus ( “leptodactyliform” body - term defined by Ribeiro et al. 2015 - and cryptic coloration). The absence of dermal ossification distinguishes the new species from B. alipioi , B. bufonoides , B. crispus , B. darkside , B. ephippium , B. garbeanus , B. guarani , B. ibitinga , B. margaritatus , B. nodoterga , B. pitanga , B. rotenbergae , B. toby , and B. vertebralis (some degree of hyperossification of the skull and skeleton in these species; Ribeiro et al. 2015; Condez et al. 2021; Nunes et al. 2021).

From species with “bufoniform” body, some degree of dorsal yellow-orangish coloration (except B. curupira and B. brunneus that present brown dorsal coloration, B. olivaceus and some specimens of B. actaeus that present dark-green dorsal coloration), and absence of dermal ossification, Brachycephalus tabuleiro differs by the following characteristics: (1) small body size SVL 9.57-11.10 mm in males, 10.88-12.70 mm in females [males SVL 11.6-12.5 mm and females SVL 13.0-14.5 mm in B. ferruginus ( Alves et al. 2006); males SVL 12.0-13.3 mm and females SVL 14.1-15.8 mm in B. pernix ( Pombal et al. 1998); males SVL 12.6-13.9 and females SVL 14.6-15.3 mm in B. pombali ( Alves et al. 2006); and females of the following species: SVL 12.5-13.1 mm in B. izecksohni ( Ribeiro et al. 2005); 13.5-13.8 in B. tridactylus ( Garey et al. 2012) (see Table 1 for more measurements)]; (2) proportionally shorter head relative to body length (HL/SVL 19-28%; mean 23 ± 3) for the 16 adult examined specimens [28-34% in B. albolineatus (Monteiro et al. 2018); 29-38% in B. auroguttatus ( Ribeiro et al. 2015); 31-36% in B. boticario ( Ribeiro et al. 2015); 33-41% in B. brunneus ( Ribeiro et al. 2005); 35-40% in B. ferruginus ( Alves et al. 2006); 29-34% in B. fuscolineatus ( Ribeiro et al. 2015); 31-35% in B. leopardus ( Ribeiro et al. 2015); 29-36% in B. mariaeterezae ( Ribeiro et al. 2015); 32-36% in B. olivaceus ( Ribeiro et al. 2015); 36-39% in B. pombali ( Alves et al. 2006); 31-36% in B. quiririensis ( Pie and Ribeiro 2015); 30-36% in B. verrucosus ( Ribeiro et al. 2015)]; (3) proportionally larger eye diameter related to head length (ED/HL 36-56%, mean 49 ± 5) [20-29% in B. brunneus ( Ribeiro et al. 2005); 23-28% in B. ferruginus ( Alves et al. 2006); 26-36% in B. olivaceus ( Ribeiro et al. 2015); 23-27% in B. pombali ( Alves et al. 2006); 28-34% in B. quiririensis ( Pie and Ribeiro 2015)]; (4) dorsum texture rough [smooth in B. brunneus ( Ribeiro et al. 2005), B. coloratus ( Ribeiro et al. 2017), B. curupira ( Ribeiro et al. 2017), B. ferruginus ( Alves et al. 2006), B. izecksohni ( Ribeiro et al. 2005), B. leopardus ( Ribeiro et al. 2015), B. pernix ( Pombal et al. 1998), B. pombali ( Alves et al. 2006), and B. tridactylus ( Garey et al. 2012)]; (5) snout shape rounded in lateral and dorsal views [semicircular in dorsal view in B. coloratus ( Ribeiro et al. 2017), B. mirissimus (Pie et al. 2018), and B. pernix ( Pombal et al. 1998); mucronate in dorsal view in B. brunneus ( Ribeiro et al. 2005) and B. quiririensis ( Pie and Ribeiro 2015); and slightly truncated in dorsal and lateral views in B. leopardus ( Ribeiro et al. 2015)]; (6) olive green general color with head, arms and legs yellow-orangish scattered with olive green, and an orangish vertebral stripe spotted with grey and brown colors [brown in B. brunneus ( Ribeiro et al. 2005); bright yellow or orange general dorsal body color in B. auroguttatus ( Ribeiro et al. 2015), B. boticario (Pie et al. 2015), B. coloratus ( Ribeiro et al. 2017), B. ferruginus ( Alves et al. 2006), B. fuscolineatus (Pie et al. 2017), B. izecksohni ( Ribeiro et al. 2005), B. leopardus ( Ribeiro et al. 2015), B. mariaeterezae (Bornschein et al. 2015), B. mirissimus ( Pie et al. 2018a), B. quiririensis ( Pie and Ribeiro 2015), B. pernix ( Pombal et al. 1998), B. pombali ( Alves et al. 2006), and B. tridacylus ( Garey et al. 2012)]; (7) finger IV greatly reduced, represented externally by a small lump [finger IV absent in B. tridactylus ( Garey et al. 2012); (8) tips of the fingers I, II, and III rounded [finger II pointed in B. brunneus and B. leopardus ( Ribeiro et al. 2005; Ribeiro et al. 2015); finger III pointed in B. auroguttatus ( Ribeiro et al. 2015), B. brunneus ( Ribeiro et al. 2005), B. coloratus ( Ribeiro et al. 2017), B. curupira ( Ribeiro et al. 2017), B. ferruginus ( Alves et al. 2006), B. fuscolineatus (Pie et al. 2015), B. leopardus ( Ribeiro et al. 2015), B. olivaceus (Bornschein et al. 2015), B. pombali ( Alves et al. 2006), B. quiririensis ( Pie and Ribeiro 2015), and B. verrucosus ( Ribeiro et al. 2015); all fingers pointed in B. pernix ( Pombal et al. 1998) and B. izecksohni ( Ribeiro et al. 2005)]; (9) toes I and V not visible externally, toe II greatly reduced, toe III short and distinct, and toe IV larger and robust [toe II short and distinct in B. auroguttatus ( Ribeiro et al. 2015), B. boticario (Pie et al. 2015), B. coloratus ( Ribeiro et al. 2017), B. curupira ( Ribeiro et al. 2017), B. fuscolineatus (Pie et al. 2015), B. leopardus ( Ribeiro et al. 2015), B. izecksohni ( Ribeiro et al. 2005), B. mariaterezae (Bornschein et al. 2015), B. mirissimus (Pie et al. 2018), B. olivaceus (Bornschein et al. 2015), B. pombali ( Alves et al. 2006), B. quiririensis ( Pie and Ribeiro 2015), B. tridactylus ( Garey et al. 2012), and B. verrucosus ( Ribeiro et al. 2015)]; (10) tips of the toes II, III, and IV rounded [II pointed in B. albolineatus (Bornschein et al. 2016), B. brunneus ( Ribeiro et al. 2005), B. ferruginus ( Alves et al. 2006), B. izecksohni ( Ribeiro et al. 2005), and B. quiririensis ( Pie and Ribeiro 2015); III pointed in B. leopardus ( Ribeiro et al. 2015); IV pointed in B. actaeus (Monteiro et al. 2018), B. ferruginus ( Alves et al. 2006), and B. quiririensis ( Pie and Ribeiro 2015)]; (11) frontoparietal and sphenethmoid not fused [frontoparietal and sphenethmoid fused in B. actaeus (Monteiro et al. 2018) and B. coloratus ( Ribeiro et al. 2017)]; (12) premaxillary odontoids presents [absent in B. coloratus ( Ribeiro et al. 2017)]; (13) relative lengths of the transverse processes in descending order: III> IV> V> II> VI> VII>VIII [III> IV> V ≅ VI ≅ VII> VIII ≅ II in B. brunneus ( Ribeiro et al. 2005); III> IV> II> V ≅ VI ≅ VII ≅ VIII in B. ferruginus and B. pombali ( Alves et al. 2006)]; (14) radius and ulna fused [not fused in B. brunneus ( Ribeiro et al. 2005), B. ferruginus ( Alves et al. 2006), B. izecksohni ( Ribeiro et al. 2005), and B. pombali ( Alves et al. 2006)] (Fig. 6 ).

The advertisement call with one note of Brachycephalus tabuleiro differs from most of its congeners by a presence of pulsed notes with a lower number of pulses per note (2-4) [(13-17 in B. bufonoides ( Folly et al. 2020), 7-12 in B. crispus ( Condez et al. 2014), 5-8 in B. darkside ( Guimarães et al. 2017), 5-15 in B. ephippium ( Pombal et al. 1994), 4-5 in B. hermogenesi ( Verdade et al. 2008), 8-12 in B. ibitinga ( Condez et al. 2021), 7-14 in B. pitanga ( Araújo et al. 2012), 8-13 in B. rotenbergae ( Nunes et al. 2021), 4-7 in B. sulfuratus ( Condez et al. 2016)]. Based on a call-centered approach, the advertisement call of the new species can be emitted with one or two notes (Fig. 7 ). Considering calls with one note, the advertisement call of Brachycephalus tabuleiro sp. nov. reaches longer duration (0.028-0.062 s) than B. albolineatus (note duration 0.002-0.037 s; Bornschein et al. 2018), and B. mirissimus (note duration 0.002-0.027 s; Pie et al. 2018a), and is shorter than B. bufonoides (note duration 0.222-0.308 s; Folly et al. 2020), B. crispus (note duration 0.280 s; Condez et al. 2014), B. darkside (note duration 0.083-0.163 s; Guima-rães et al. 2017), B. ephippium (note duration 0.093-0.125 s; Pombal et al. 1994), B. hermogenesi (note duration 0.200 s; Verdade et al. 2008), B. ibitinga (note duration 0.180-0.250 s; Condez et al. 2021), B. pitanga (note duration 0.150-0.250 s; Araújo et al. 2012), B. rotenbergae (note duration 0.130-0.140 s; Nunes et al. 2021), B. sulfuratus (note duration 1.500-2.300 s; Condez et al. 2016), and B. tridactylus (note duration 0.110 s; Garey et al. 2012). Regarding the dominant frequency, the advertisement call of the new species (6,115.4-6,546.0 Hz) is higher than B. bufonoides (4,130-4,880 Hz, Folly et al. 2020), B. crispus (3,500-5,700 Hz, Condez et al. 2014), B. darkside (2,856.4-3,796.9 Hz, Guimarães et al. 2017), B. ibitinga (4000-4300 Hz, Condez et al. 2021), B. pitanga (4,900 Hz, Araújo et al. 2012), B. rotenbergae (2,840-4,520 Hz, Nunes et al. 2021), and B. tridactylus (4800 Hz, Garey et al. 2012), and lower than B. actaeus (6,600-7,300 Hz, Monteiro et al. 2018a), B. hermogenesi (6,800 Hz, Verdade et al. 2008), and B. olivaceus (6,400-7,000 Hz, Monteiro et al. 2018b). In addition, pulse duration of the advertisement call of the new species (0.003-0.009 s) lasts shorter than B. crispus (pulse duration 0.027 s, Condez et al. 2014), B. olivaceus (pulse duration 0.015-0.025 s; Monteiro et al. 2018b), B. quiririensis (pulse duration 0.012-0.017 s; Monteiro et al. 2018b), and B. sulfuratus (pulse duration 0.020-0.030 s; Condez et al. 2016). For more detail and complete comparison, see Table 2 .

Description of the Holotype.

Body robust, “bufo-ni-form”; head wider than long, head length 20% of SVL; snout short, rounded in dorsal and lateral views; nostrils elliptical and protuberant; canthus rostralis distinct and straight; loreal region slightly concave; eyes oriented anterolaterally; eye diameter 52% (range) of head length; tympanum absent; lips nearly sigmoid; vocal sac not expanded externally; elongated vocal slits; tongue elliptic, longer than wide, with the posterior half not adherent to floor of mouth; vomerine teeth absent; choanae small and rounded, anterior to eyes, separated from each other. Arm and forearm moderately slender; hands with fingers I and IV greatly reduced, represented externally by a small lump; finger II reduced but distinct, and finger III larger and robust; fingertips I, II, and III rounded; finger lengths IV <I <II <III; subarticular tubercles absent; inner and outer metacarpal tubercles absent. Legs relatively short, moderately robust; thigh length 34% (range) of SVL, tibia length 92% (range) of thigh length; toes I and V present but externally indistinguishable, toe II greatly reduced, toe III short and distinct, and toe IV larger and robust; toe lengths II <III <IV; tips of the toes II, III, and IV rounded; subarticular tubercles absent; inner and outer metatarsal tubercles absent. Skin on top of the head smooth; dorsal body rough and without dermal co-ossification. Skin on dorsolateral and dorsal surfaces of legs rough; dorsal surface of arms smooth. Ventral surface of the skin is rough, evenly across the body.

Measurements of the holotype (in mm).

SVL 10.40; HL 2.09; HW 4.29; ND 0.18; IND 1.12; ED 1.08; IOD 2.48; END 0.48; THL 3.50; TBL 3.22; FL 3.87; UAL 1.63; FAL 2.54; HAL 1.91.

Color of holotype in life.

General dorsal body color olive green, with a thin the vertebral stripe white margined of brown blotches; head is orange scattered with olive green, gray, and brown colors; legs are green gradually changing to an orange color on the knees, heels, and toes; arms and hands are orange, spotted brown; fingers are orange. In lateral view, the head is mostly orange, with eye and naris contour, and the upper lip brown. In ventral view, the general background color is orange; dark olive green blotches are present on the throat, cloacal region, and side of the body, extending toward the dorsum (Figs 3 , 4 ).

Color of holotype in preservative.

After seven years in preservative, general dorsal body color dark brown, with the head and the vertebral stripe light gray; legs brown gradually fading to a cream color on the knees and heels; arms and hands cream, spotted brown, with elbows cream; fingers and toes are cream. In lateral view, head is mostly cream, with eye and naris contour, and the upper lip brown. In ventral view, general background color is cream; brown blotches are present on the throat, cloacal region, and side of the body, extending toward the dorsum; irregular brown spots are distributed on the belly, legs, fingers, and toes (Fig. 5 ).

Osteology.

The Skull is slightly wider than long in dorsal view, without hyperossification. Premaxillae broad, not fused medially, reduced odontoids present in par dentalis; alary process distinct, taller than wide and separated of nasals; posteromedial process distinct, posteromedial process reduced. Maxillae elongated and arched with reduced odontoids in par dentalis; par facialis reduced with anterior region smaller than the posterior one; preorbital processes distinct, long and anterodorsally oriented; the pars palatine extend from the anterior tip of the maxilla to the base of the posterior process and presents the anterior third larger than the posterior one. The quadratojugals is present, slender, with the maxillary process pointed. Nasals widely separated medially and presents an irregular trapezoidal shape in dorsal view; nasals and sphenethmoid fused, the paraorbital process is absent. Frontoparietals paired, not fused, rectangular shaped, frontoparietal fontanelle roofed; anteriorly the frontoparietals overlap the posterior margin of the sphenethmoid. Vomers cartilaginous and reduced with the prechoanal and postchoanal process ossified. Frontoparietals, prootics, and exoccipitals fused. Neopalatines absent. Parasphenoid is cross-shaped without ornamentation; the cultriforme process is broad and touches the sphenethmoid; lateral alary processes are long. Squamosal is T-shaped in lateral view; the anterior zygomatic ramus is short, with approximately 1/4 of posterior otic ramus length and expanded dorsoventrally at its anterior margin; posterior ramus is approximately at same length of the ventral ramus and projected posterodorsally. The ventral ramus is large and slightly expanded ventrally. The lateral surface of the ventral process is flat; the lamina alaris in the bases of the anterior processes is concave. The pterygoids are slender and T-shaped; the tips of the anterior and posterior ramus are acuminated, tips of the medial ramus are truncated; the anterior ramus is the longest and does not articulate with the maxilla; the posterior ramus is shortest and articulating with the ventral ramus of the squamosal; the short and broad medial ramus articulating with the prootic; the anterior and medial ramus form a straight margo orbitalis. The exoccipitals, and prootics are fused, these bones form the posterior part of the skull; each paired occipital condyle has a marked base and a distal, rounded head. Operculum not ossified. Tympanic annulus and columellae absent. Mandible elongated and edentate, compound by a large angulosplenial, by a reduced cartilaginous dentary and a small mentomecklian cartilage. The Hyoid apparatus is formed by the central corpus, by the hyale anteriorly, by the posterlateral process and by an ossified posteromedial processes; the corpus hyoid is cartilaginous, rectangular and longer than wide; the cartilaginous hyale are long and project anteriorly from the anterolateral margins of the corpus hyoid; a long anterior process of hyale is present; the alary processes of the hyoid are poorly developed; the posterolateral process is short and triangular; the posteromedial processes are long, well ossified, the proximal and distal ends of the posteromedial processes are wider. The pectoral girdle is arciferal, composed by the fusion of the clavicle, coracoid, and scapula; epicoracoid completely ossified and fused with the coracoid; the procoracoid cartilages are continuous with the epicoracoid medially and are partially ossified. Suprascapula fused with coracoid and scapula; sternum and omosternum are not present. Skeleton without hyperossification. Vertebral column composed of eight presacral, procoelous and nonimbricate vertebrae; dorsal ossification of neural arches is complete; the atlas does not present transverse process that is present in all other presacral vertebrae; the relative lengths of the transverse processes in descending order are: III> IV> V> II> VI> VII> VIII; neural spines are not evident. The sacral diapophyses extend posterolaterally and are expanded distally. The distal ends of the sacral diapophyses are cartilaginous and overlie the anterior ends of the ilial shafts. The urostyle is long and slender with approximately 2/3 of the length of the presacral, the urostyle presents a dorsal longitudinal ridge that is higher anteriorly and decreases in height posteriorly. Pelvic girdle V-shape in dorsal view, composed by a fused ilium, pubis, and ischium; each ilial shaft has a low longitudinal crest that decreases in height in the anterior third. The acetabulum is completely ossified with well-defined margins. Forelimbs with humerus slightly curved, with a small crest at the proximal end of the ventral surface; radius and ulna with sulcus intermedius distinct. Manus with distal carpals 3-4-5 and distal carpal 2 presents; radiale and ulnare about the same size; prepollex elements very reduced with one prepollical element; phalangeal formula 1-2-3-1; tips of the terminal phalangeal elements arrow-shaped in fingers I-III, rounded in finger IV. Hindlimbs with tibia and fibula fused; femur and tibiofibula of approximately the same length; fibulare and tibiale fused distal and proximally but separated in the middle portion. Pes with distal tarsal 2-3 and distal tarsal 1 presents; phalangeal formula 1-2-3-4-0. Tips of the terminal phalangeal elements arrow-shaped in toes II-IV, rounded in toes V (Fig. 6 ).

Advertisement call.

The advertisement call of Brachycephalus tabuleiro sp. nov. is characterized by one multipulsed note (76.2% of all calls, n = 34), or in a sequence of two multipulsed notes (23.8% of all calls, n = 10; Fig. 7 , Table 2 ). Calls with one note present 2 to 4 pulses, a duration of 0.037 ± 0.009 second (0.028-0.062 s, n = 34 calls), in an interval between calls 6.52 ± 2.0 seconds (2.07-11.25 s, n = 31 intervals), the mean of fundamental frequency 3,914 ± 902.9 Hz (2,394-5,264 Hz, n = 34 calls), dominant frequency 6,399 ± 103.4 Hz (6,115-6,546 Hz, n = 34 calls) and bandwidth 90% 583.8 ± 141.8 Hz (430.7-937.5 Hz, n = 34 calls). Calls with two notes were emitted sequentially by one male, but other males regularly vocalized with two notes, recorded in the background. Calls with two notes present a duration of 0.568 ± 0.02 second (0.541-0.628 s, n = 10 calls), in an interval between calls 11.31 ± 1.6 seconds (10.03-13.94 s, n = 9 intervals). The note one present 3 or 4 pulses, duration 0.069 ± 0.01 second (0.057-0.075 s, n = 10 notes), fundamental frequency 3,618 ± 332.0 Hz (3,040-4,090 Hz, n = 10 notes), dominant frequency 6,124 ± 27.2 Hz (6,115-6,202 Hz, n = 10 notes) and Bandwidth 90% 628.8 ± 81.7 Hz (516.8-775.2 Hz, n = 10 notes). The note two also present 3 or 4 pulses, duration 0.058 ± 0.01 second (0.050-0.071 s, n =10 notes), fundamental frequency 3621 ± 241.9 Hz (3,269-4,034 Hz, n = 10 notes), dominant frequency 6,115 ± 0 Hz (n = 10 notes) and Bandwidth 90% 611.5 ± 48.9 Hz (516.8-689.1 Hz, n = 10 notes). The interval between notes of calls with two notes was in mean 0.436 ± 0.03 second (0.415-0.507 s, n = 10 intervals), note rate of 3.53 ± 0.14 notes/second (3.18-3.70 notes/s, n = 10 calls). All the notes emitted, both in the calls with one and in the calls with two notes, had an average of 3 pulses/note ± 0.49 (2-4 pulses/note, n = 54 notes), and the two first pulses are the most energetics, followed by a decrease in amplitude in the third and fourth pulses.

Variation.

The general dorsal body color varies from a dark olive green to a lighter green with some shades of yellow; the vertebral stripe can be well marked with an orangish line spotted with gray and brown colors, with some individuals exhibiting an irregular gray vertebral stripe (not well marked as a continuous and thin line). The head is orange scattered with olive green and brown colors, and some individuals present the head almost completely orange with few gray blotches and without the green color. The ventral background is orange, with some individuals presenting this region with green reticulated spots (Fig. 5 ). Descriptive statistics of measurement variables from adults are presented in Table 1 .

Molecular analysis.

Our tree topology (Fig. 8 ), based only on the 16S mDNA, recovered the B. pernix group monophyletic (pp = 1.00). The new species belongs to one of the clades (pp = 1.00) within the B. pernix group formed by B. actaeus , B. albolineatus , B. auroguttatus , B. boticario , B. coloratus , B. ferruginus , B. fuscolineatus , B. mariaterezae , B. mirissimus , B. olivaceus , B. pernix , B. pombali , B. quiririensis , and B. verrucosus . We refrain to further discussion about species relationships based on the small fragment of mtDNA used for this analysis. For a better overview on Brachycephalus phylogeny, see Condez et al. (2020), in which three mitochondrial genes were used to recover the species relationships. Average sequence divergences between the new species and congeners in the clade where it is nested ranged from 1.1% ( B. auroguttatus , B. coloratus , B. mariaeterezae , B. olivaceus ) to 5.1% ( B. mirissimus ) (Table 3 ; Table S2).

Natural History.

Brachycephalus tabuleiro is diurnal. We found all specimens on the forest floor amidst leaf litter (0-70 mm under surface, n = 9 individuals). Males calling on the leaf litter, below one or more dry leaves (n = 3 individuals) or upside down (n = 1 individual). One female was found on leaf litter nearby and turned towards a male calling. We observed greater intensity and abundance of vocalization at the beginning of the day (7 a.m.) and at the end of the afternoon (18 p.m.) (dawn/dusk). On days with rain or intense cloudiness, males appear to be active throughout the day. However, on sunny days, at warmer times (10 a.m. to 4 p.m.), the vocal activity and abundance of vocalizing males decreases or neither occurs. We recorded two potentially defensive behaviors for males and females: the mouth-gaping (Fig. 4A-B ) and, remaining motionless with arms and legs extended, enabling individuals to be rolled during leaf litter removal (Fig. 4C-D ). The mouth-gaping behavior has already been reported for other species of Brachycephalus ( Toledo et al. 2011).

Distribution.

Brachycephalus tabuleiro is known from one locality in São Bonifácio municipality, to the Parque Estadual da Serra do Tabuleiro, a protected area in Santa Catarina state, Brazil (Fig. 9 ). Although the type series was collected outside the Park boundaries, we also recorded males calling inside the protected area.

Etymology.

The species is named for the type locality in the Serra do Tabuleiro. The Parque Estadual da Serra do Tabuleiro is the largest remnant of the Atlantic Rainforest in southern Brazil.

Conservation remarks.

There is significant anthropogenic interference around the type locality of the new species, both in and around the Parque Estadual da Serra do Tabuleiro. The type locality is beside a dirt road, at the park boundaries (Fig. 10 ). In this area we observe various agricultural activities such as: (i) Apis mellifera apiculture; (ii) bovine cattle; and (iii) forestry of Pinus sp. and Eucalyptus sp. All these animals and plants are introduced exotic species. The presence of exotic plants can change the amount and the quality of leaf litter (e.g., Liao et al. 2007; Sausen et al. 2014), somehow compromising the population of B. tabuleiro on type locality. Another aggravating factor is that the municipality of São Bonifácio has conflicts over land use with irregular occupation and unfinished expropriation processes in Parque Estadual da Serra do Tabuleiro ( IMA 2018). In addition, criminal fires and the lack of land regulation have compromised the conservation of this protected area. Brachycephalus tabuleiro is probably a mountaintop microendemic species like most species of the B. pernix group (e.g., Pie and Ribeiro 2015; Bornschein et al. 2016a; Ribeiro et al. 2017; Condez et al. 2020).

Figures

Figure 1. Holotype of Brachycephalus tabuleiro (MNRJ 93859, adult male, SVL 10.40 mm) from Serra do Tabuleiro, Sao Bonifacio municipality, Santa Catarina state, Brazil. (A) Dorsal and (B) ventral views.

Figure 2. Holotype of Brachycephalus tabuleiro (MNRJ 93859, adult male, SVL 10.40 mm) from Serra do Tabuleiro, Sao Bonifacio municipality, Santa Catarina state, Brazil. (A) Lateral view of the head, ventral views of the (B) hand and the (C) foot.

Figure 3. Live specimens of Brachycephalus tabuleiro. A UNIFESSPA 113 (adult male), B MHNCI 11498 (adult female), C MNRJ 93859 (adult male, holotype), D MHNCI 11498 (adult female), E MNRJ 93859 (adult male, holotype) and UNIFESSPA 113 (adult male), F CHSA. A 1404 (adult female), G and H ZUFMS-AMP 14531 (adult not sexed). Photos: Diego Jose Santana (A, B, C, D, E), Milena Wachlevski (F, G, H).

Figure 4. Behavior. A MHNCI 11498 (adult female), B UNIFESSPA 113 (adult male), C ZUFMS-AMP 14531 (adult not sexed), D UNIFESSPA 112 (adult male). Photos: Diego Jose Santana (A, B), Milena Wachlevski (C, D).

Figure 5. Morphological and color variation of preserved specimens of Brachycephalus tabuleiro from Serra do Tabuleiro, Sao Bonifacio municipality, Santa Catarina state, Brazil. A UNIFESSPA 113 (adult male), B CFBH 45452 (adult not sexed), C MNRJ 93856 (adult not sexed), D CHSA. A 1403 (adult male), E MNRJ 93857 (adult not sexed), F MNRJ 93854 (adult male), G MNRJ 93857 (adult not sexed), H MNRJ 93855 (adult male), I CHSA. A 1404 (adult female), J UNIFESSPA 112 (adult male), K ZUFMS-AMP 14532 (adult male), L ZUFMS-AMP 14531 (adult not sexed), M MHNCI 11499 (adult female), N MHNCI 11498 (adult female), O MNRJ 93859 (adult male, holotype).

Figure 6. Brachycephalus tabuleiro. (A) Dorsal views of the skull, (B) vertebrae, and (C) dorsal views of the left foot and (D) hand (UNIFESSPA 112).

Figure 7. Advertisement calls of Brachycephalus tabuleiro recorded at Serra do Tabuleiro, Sao Bonifacio municipality, Santa Catarina state, Brazil. (A) Call sequence of three calls with only one note each, (B) the spectrogram and (C) oscillogram of one highlighted call (CASA 154). (D) Call sequence of three calls with two notes each, (E) the spectrogram and (F) oscillogram of one highlighted call (with two notes) (CASA 157).

Figure 8. Inset of the maximum clade credibility 16 S rRNA mitochondrial gene tree as inferred from a Bayesian analysis in BEAST. Section of the phylogenetic analysis of the 16 S mtDNA gene for the genus Brachycephalus. Scale indicates rate of base substitutions per site.

Figure 9. Geographic distribution of Brachycephalus tabuleiro and of the more closely related species within the B. pernix group, formed by: B. actaeus, B. albolineatus, B. auroguttatus, B. boticario, B. coloratus, B. ferruginus, B. fuscolineatus, B. mariaterezae, B. mirissimus, B. olivaceus, B. pernix, B. pombali, B. quiririensis, and B. verrucosus.

Figure 10. Type locality environment of Brachycephalus tabuleiro at Serra do Tabuleiro, Sao Bonifacio municipality, Santa Catarina state, Brazil.