Fritziana mitus, Walker & Wachlevski & Nogueira-Costa & Garcia & Haddad, 2018

Walker, Marina, Wachlevski, Milena, Nogueira-Costa, Paulo, Garcia, Paulo C. A. & Haddad, Célio F. B., 2018, A New Species of Fritziana Mello-Leitão 1937 (Amphibia: Anura: Hemiphractidae) from the Atlantic Forest, Brazil, Herpetologica 74 (4), pp. 329-341 : 329-341

Fritziana mitus sp. nov.

( Figs. 1–3 ; Table 1 )

Flectonotus fissilis : Del Pino 1980:11, in part; Dixo and Verdade 2006:4; Condez et al. 2009:161.

Fritziana fissilis : Duellman and Gray 1983:359, in part; Heyer et al. 1990:356; Duellman et al. 2011:31; Blackburn and Duellman 2013:712; Folly et al. 2014:399, in part.

Fritziana aff. fissilis : Wachlevski et al. 2014:100; Franz and Mello 2015:4; Ceron et al. 2017:296; Comitti 2017:94.

Fritziana ulei : Folly et al. 2014:399, in part; Menegucci et al. 2017:1.

Holotype. — CFBH 39949 , an adult female collected in an Atlantic Forest area in the Parque Estadual da Serra do Tabuleiro (27 º 44 ' 30 '' S, 48 º 48 ' 28 '' W; 420 m above sea level; datum = WGS84), municipality of Santo Amaro da Imperatriz, Santa Catarina State, Brazil, by Milena Wachlevski, on 14 April 2010 ( Figs. 1 and 2 ). The holotype was collected by active search (at 2130 h) in a bromeliad ( Vriesea sp. ) at a height of 60 cm in relation to the soil .

Paratopotypes. — Ten specimens consisting of six adult females without eggs on the dorsum ( CFBH 39932 - 39935 , CHUFSC 2625 , and MNRJ 90352 ), two adult females incubating eggs on the dorsum ( CFBH 39936 and MNRJ 90351 ), and two adult males ( CFBH 39937 and MNRJ 90350 ). These specimens were collected in the municipality of Santo Amaro da Imperatriz, Santa Catarina state, Brazil, between July 2009 and January 2013 .

Diagnosis. —Based on 26 males and 24 females collected throughout the known distribution area of the new species (Appendix I), the new species is characterized by the following: (1) TD equal to 89% of the DTIV (females, 55– 115% [87 ± 15%, n = 24]; males, 59–135% [91 ± 18%, n = 26]); (2) HW equal to 93% of the HL (females, 84–109% [95 ± 6%, n = 24]; males, 78–102% [91 ± 6%, n = 26]); (3) a mucronate snout tip; (4) distal subarticular tubercles which are simple and round on the hands and feet; (5) the most common color pattern characterized by an interorbital triangle followed posteriorly by two parallel lines on the dorsum; (6) a black stripe on the wrist; (7) an egg-brooding pouch on the back of the females with the skin covering the eggs, and with a medial opening (the pouch in the reproductive period is evident even when empty); (8) tadpoles deposited in bromeliads; and (9) a change in the mitochondrial tRNA gene order (instead of having the order proline–phenylalanine–12S, the new species has the order phenylalanine–proline–12S).

Comparisons with other species. —On average, Fritziana mitus sp. nov. is small when compared to other species within the genus. Therefore, large specimens of F. mitus sp. nov. might overlap in size with small specimens of F. ohausi , F. goeldii , F. tonimi , and F. izecksohni (SVL: F. mitus sp. nov.: males = 16.16–23.67 mm [19.97 ± 1.65 mm, n = 26], females = 17.43–28.35 mm [24.28 ± 2.47 mm, n = 24]; F. tonimi : males = 21.4–26.62 mm [23.67 ± 1.71 mm, n = 14], females = 27.04–31.20 mm [28.72 ± 1.90 mm, n = 4]; F. goeldii : males = 19.52–30.16 mm [27.12 ± 2.69 mm, n = 21], females = 30.41–37.03 mm [34.16 ± 3.47 mm, n = 7]; F. ohausi : males = 18.74–31.57 mm [26.80 ± 3.11 mm, n = 43], female = 27.6 mm [n = 1]; F. fissilis : males = 25.51– 29.97 mm [n = 2], females = 28.29–31.68 mm [30.13 ± 1.63 mm, n = 5]; F. ulei : males = 21.68–27.59 mm [23.24 ± 1.56 mm, n = 14], females = 23.07–25.07 mm [n = 2]; F. izecksohni : males = 21.5–29.4 mm [25.9 ± 2.8 mm, n = 5], female = 33.5 mm [n = 1]).

The TD:DTIV ratio is larger in Fritziana mitus sp. nov. than in the other species except in F. goeldii (TD/DTIV = 0.89 in F. mitus sp. nov., females = 0.55–1.15 [0.87 ± 0.15, n = 24], males = 0.59–1.35 [0.91 ± 0.18, n = 26]; 0.79 in F. fissilis , females = 0.70–0.88 [0.77 ± 0.07, n = 5], males = 0.73–0.95 [n = 2]; 0.99 in F. goeldii , females = 0.92–1.31 [1.09 ± 0.12, n = 7], males = 0.61–1.38 [0.95 ± 0.16, n = 24]; 0.84 in F. tonimi , females = 0.72–1.18 [0.90 ± 0.22, n = 4], males = 0.64–0.98 [0.83 ± 0.11, n = 14]; 0.70 in F. ohausi , female = 0.78 [n = 1], males = 0.42–0.96 [0.70 ± 0.14, n = 43]; and 0.70 in F. ulei , females = 0.75–0.78 [n = 2], males = 0.42–0.96 [0.69 ± 0.13, n = 14]). Fritziana mitus sp. nov. has a proportionately wider head than F. ohausi and F. izecksohni , and a longer head than the other species (mean HW/HL for males = 0.93 in F. mitus sp. nov., females = 0.84–1.09 [0.95 ± 0.06, n = 24], males = 0.78–1.02 [0.91 ± 0.06, n = 26]; 0.83 in F. izecksohni ; 0.86 in F. ohausi males = 0.79–0.96 [0.86 ± 0.04, n = 43]; 0.94 in F. goeldii , females = 0.90–1.01 [0.96 ± 0.04, n = 7], males = 0.89–1.01 [0.89 ± 0.03, n = 24]; 0.91 in F. tonimi , females = 0.89–0.94 [0.93 ± 0.02, n = 4], males = 0.84–0.98 [0.90 ± 0.04, n = 14]; 0.95 in F. ulei , females = 0.94–0.99 [n = 2], males = 0.91–1.99 [0.95 ± 0.03, n = 14]; and 0.93 in F. fissilis , females = 0.87– 1.00 [0.93 ± 0.05, n = 5], males = 0.88–0.97 [n = 2]).

Fritziana mitus sp. nov. differs from F. fissilis and F. ohausi by having a mucronate snout tip (the tip of the snout is not mucronate in F. fissilis and in F. ohausi ), and differs from F. fissilis and F. izecksohni by having round subarticular tubercles on all the fingers and toes (subarticular tubercles are bifid in F. fissilis and F. izecksohni ).

Although Fritziana mitus sp. nov. can exhibit a uniform color pattern ( Fig. 3F ) or a bronze blotch covering the entire dorsal surface of the head (similar to F. ulei , Folly et al. 2014); the most common pattern ( Fig. 3A ) is characterized by an interorbital triangle (also present in F. goeldii , F. ohausi , and F. tonimi ) followed posteriorly by two parallel lines on the dorsum (a bilobated stain in F. goeldii and F. tonimi ; an inverted V in F. ohausi ). The type series of F. fissilis is discolored, but the dorsal pattern described in the original description seems to be similar to the pattern of the new species. Folly et al. (2014) noted the presence of an hourglass-shaped interorbital mark in other specimens identified by them as F. fissilis . Fritziana izecksohni exhibits a triangular mark covering the dorsum to the sacral region, but few specimens are known, and the occurrence of other patterns is possible. Fritziana tonimi can also have two long lines from the eye to the cloacal region forming a large V. The black stripe on the wrist is present in only the new species.

Fritziana mitus sp. nov. differs from F. goeldii , F. ohausi , and F. tonimi , by having a closed dorsal pouch in females during egg incubation (as opposed to an opened pouch in F. goeldii , F. ohausi , and F. tonimi ). Although the holotype of F. izecksohni shows dorsal folds on its back, indicating a closed dorsal pouch, no recorded observation of a female transporting eggs has occurred; therefore, its pouch morphology remains unknown. The new species further differs from F. ohausi on account of its reproductive behavior of releasing tadpoles into bromeliads (tadpoles are released into bamboo by F. ohausi ). Although Folly et al. (2018) suggested that tadpoles of F. izecksohni develop in bromeliads, no clutch or tadpoles have been observed, so the microhabitat for this life-history stage remains unknown for F. izecksohni .

The new species differs from Fritziana fissilis , F. goeldii , F. ohausi , F. tonimi , and F. ulei by possessing a unique order of mitochondrial genes. Instead of the most common neobatrachian gene order (proline–phenylalanine–12S; Zhang et al. 2013), the new species has an order of phenylalanine–proline–12S ( Walker et al. 2018: Fig. 4 ). The gene order in F. izecksohni remains unknown.

Description of holotype. —Adult female without eggs on dorsum; head wider than long; HL 33% of SVL; snout rounded with tip slightly mucronate in dorsal view, protruding in lateral view. Nostril elliptical and protuberant, laterally oriented; IND 17% of the HW. Canthus rostralis distinct and straight; loreal region straight. Tympanum slightly evident; tympanic annulus hidden beneath skin; TD 35% of ED; supratympanic fold slightly developed. Postrictal tubercles absent. Eye oriented anterolaterally, its diameter 35% of HW; IOD 33% of HW; upper eyelid and interorbital region with small tubercles. Tongue ovoid, free on its posterior portion, and lacking a posterior notch; vomerine teeth in two oblique series that are next to each other; choanae large and rounded, well separated from each other. Dorsum smooth, belly areolate; ventral surfaces of thigh and pericloacal area granulated; gular region smooth. Flank homogeneous in color. Cloacal opening directed posteriorly at the upper level of thighs. Row of tubercles present on forearms; adhesive discs of fingers developed, expanded, and not emarginated; interdigital webbing absent on hand; relative length of fingers: III <II <V <IV; subarticular tubercles rounded; thenar tubercle developed and elliptic; two palmar tubercles developed, elliptical, and parallel to each other. FL 41% of SVL; THL 89% of the TBL; very small calcar present; tubercle on tibia absent; row of tubercles present on the tarsus; tibia slightly longer than thigh and together approximately the same length as SVL; adhesive discs of toes moderate in size, expanded, and not emarginated; interdigital webbing absent between Toes I and II and vestigial between others; relative length of toes: I <II <III <V <IV; subarticular tubercles rounded, few supernumerary tubercles; inner metatarsal tubercle elliptic and well developed; outer metatarsal tubercle slightly evident and rounded.

Coloration of holotype. —In life, dorsal coloration of holotype brownish-yellow with a brownish interorbital fleck on the head. Dorsolateral stripe brownish with creamcolored outer edge extending from posterior margin of eye to midbody. Dorsal surface of discs on fingers dark. A dark brown band present on the wrist. In lateral view, maxilla with irregular dark spots. Venter with a uniform cream color. Iris pale bronze; a red horizontal stripe across eye ( Fig. 1 ). In preservative, the specimen has the same general color patterns, but the colors are paler and the dark surface of the finger discs is not visible.

Measurements of holotype (in mm). —SVL 24.7, HW 8.42, HL 8.13, AL 6.9, FAL 5.13, HAL 6.81, THL 11.62, TBL 13.01, TL 7.26, FL 10.1, IND 1.42, IOD 2.78, ED 2.96, END 2.47, TD 1.05, DFIV 1.09, and DTIV 1.04.

Morphological variation ( Table 1 ). —The snout is usually round in the lateral view (72.5% of the specimens), but sometimes truncate (20.7%) or protruding (6.8%). In the dorsal view, it is round (34.5%) or truncate (31%), but can also be pointed (17.25%) or subovoid (17.25%). The snout tip is slightly mucronate in the majority of specimens (86.25%), but not mucronate in others (13.75%).

The dorsal skin is smooth with tubercles on the upper eyelid present in the minority of preserved specimens (17.3%), but they were apparent in live specimens even though they were not visible in the same specimens when preserved. Although rare, tubercles might also be present on the snout and between the eyes. The belly is grainy and the throat might be slightly grainy or smooth, with the rest of the ventral surface smooth. A dorsolateral stripe is usually present (65.6%) and when present it begins on the snout, passes over the eye, and extends posteriorly until the tympanum, the middle of the body, or the cloacal region. A characteristic pattern is formed by an interorbital bar and two stripes; the two stripes originate on the posterior corner of the eyes and converge in the middle of the head where they extend parallel to the middle of the body ( Fig. 3A ). A small stripe might be present anteriorly and perpendicularly to the interorbital bar. Some specimens are uniformly beige with no distinct pattern (34.5%). In life, the dorsal coloration can be greenish, yellowish, bronze, or light brown. There might also be a bronze mark on the head, but this color is not visible in preserved specimens ( Fig. 1B ). Specimens mostly have only one stripe on the wrist, like a bracelet, and other stripes or dots on the forelimb are rare (10.35%). The fingertips might be blackish, but this is normally only observed in live specimens. The hind limbs usually lack any type of pattern, but on rare occasions they might have dots or stripes (20.7%). When large dots are present on the legs they can be brown, bronze, or cream ( Fig. 1B ). Also, a row of tubercles might be present on the forearms (41.4%) or more often, on the hind limbs (86.25%).

Sexual dimorphism. —During the reproductive period, females exhibit a closed dorsal pouch when transporting eggs ( Fig. 1B ). The eggs are normally distributed as a layer, without any regular pattern common to all females. Females without eggs might possess, on the dorsum, a skin crest that corresponds to the empty pouch ( Fig. 3A,E ). Females with eggs removed from their dorsum after preservation possess individual skin chambers on the dorsum. Males possess nuptial pads on the base of Finger II, which can be pale beige or brown, and vocal slits on the floor of the mouth lateral to the tongue. The vocal sac is indistinct in preserved males.

External morphology of tadpoles. —Even when belonging to the same egg clutch and being euthanized simultaneously, the tadpoles show different stages of development. In Stage 35, tadpoles have an elongated body, elliptical in both the dorsal and lateral views ( Fig. 4 ). Their BL is 39.8% of the total length ( Table 2 ). The body is wider than high; BH is 85.7% of its width. The BH is 93.7% of the TAH. The snout is rounded in dorsal view and truncate in lateral view. The eye is dorsally located, anterolaterally directed; with an ED equal to 16.9% of the BL; the nostril is closer to the tip of snout than to the eye; the distance between the eye and nostril is 63.6% of the distance between the eye and the tip of snout. The nostril is elliptical in the lateral view and the opening of the nostril is not visible dorsally. The nostril is anteriorly located and directed; the IND is 56.2% of the IOD; the distance between the nostril and the tip of snout is 8.4% of the BL.

The spiracle is sinistral, ventral, short, and with the inner wall connected to the body. The SSD is 45.7% of the BL. The vent tube is as long as it is wide, dextral, with a wide opening, and attached to the ventral fin. The TAL is 69.6% of the total length and tail musculature does not reach the tail tip, which is rounded. In the lateral view, the dorsal fin originates on the tail musculature; the dorsal fin is ascendant in the first third of the tail, then becomes parallel to the tail musculature. The ventral fin is parallel to the tail musculature ( Fig. 4 ). The oral disc is ventral and the ODW is 28.6% of the BW, bordered by a single row of papillae with a large dorsal gap ( Fig. 5 ). Submarginal rows of papillae and labial teeth are absent. Jaw sheaths are developed and completely serrated; the upper is U-shaped and the lower is V-shaped ( Fig. 5 ).

Tadpole color. —Tadpoles preserved in 5% formalin are light brown with very small dark brown blotches; the flanks are lighter than the dorsum. Laterally, the tail is light cream, adorned with small dark brown blotches concentrated in the tail musculature and in the final third of the tail. Ventrally, the body is light brown with a translucent ventral region; the yolk is visible through the skin. The spiracle, the oral disc, and the cloacal tube are translucent beige.

Molecular analyses. — Walker et al. (2018) reported the occurrence of a different gene order for mitochondrial tRNA in Fritziana mitus sp. nov. (named by them as F. CS3) that is seemingly exclusive to this species until now. If the 12S gene is amplified using the primer MVZ59 ( Graybeal 1997), the specimens show a fragment with about 200 more base pairs than in other species. We associate this with the proline tRNA gene, indicating a change in the gene order from the common neobatrachian order of proline–phenylalanine–12S, to an order of phenylalanine–proline–12S in the new species ( Walker et al. 2018). All the other species of Fritziana possess the common neobatrachian size for this fragment of tRNA ( Walker et al. 2018); however, this information is missing for F. izecksohni , whose gene order is unknown.

Complete Bayesian analyses were made for Fritziana by Walker et al. (2018) and by our group (with only part of the 16S fragment, including Fritziana izecksohni and outgroups; Fig. 6 ). Both analyses show that F. mitus clusters together, and is a sister group to only one sample from the state of Minas Gerais (F. CS 2 in Walker et al. 2018). Morphologically, this specimen is similar to F. mitus , but differs from the new species by the presence of an additional fragment in its tRNA ( Walker et al. 2018: Fig. 4 ). The few specimens collected of F. CS2 preclude proper comparisons. Fritziana CS 2 ( Walker et al. 2018) + F. mitus sp. nov. form the sister group of another new species, informally named by Walker et al. (2018) as F. CS1.

The two samples of Fritziana izecksohni used by Folly et al. (2018) might have been contaminated because they cluster with Euparkerella and Cophomantini ( Hylidae ) in the present analyses ( Fig. 6 ). This also explains the high inter- and intraspecific divergence and high length of branches found for F. izecksohni by Folly et al. (2018).

Geographical distribution. — Fritziana mitus sp. nov. occurs in the Brazilian states of São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul (Appendix I). This species possesses the largest and southernmost known distribution for the genus Fritziana ( Fig. 7 ).

Conservation status. —According to the International Union for Conservation of Nature (IUCN) Red List, Fritziana fissilis is listed as Least Concern ‘‘in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category’’ ( Carvalho-e-Silva and Telles 2010:1). With the description of F. mitus sp. nov., the known distribution of F. fissilis becomes much smaller and the amount of information about the species is insufficient to place it in one of the categories proposed by IUCN. Therefore, we believe F. fissilis should be considered Data Deficient. On the other hand, F. mitus has a wide distribution and is the more common species of the genus, and thus qualifying as Least Concern.

Etymology. —The specific epithet, mitus , is a noun derived from the Greek word µíroç, which means ‘‘thread.’’ It is a reference to the mitochondrial DNA, which possesses a gene order exclusive to this species.

Natural history. —Individuals of Fritziana mitus sp. nov. are found in epiphytic bromeliads, generally of the genus Vriesea Lindl , 1–3 m above the ground in forests, but might also be found in bushes. In the Parque Estadual da Serra do Tabuleiro, Santa Catarina State, F. mitus sp. nov. can be active at dusk and at night, and is more abundant during the rainy season (September to March). On two occasions, individuals of F. mitus sp. nov. were found moving on the forest floor and two other specimens were observed on nonbromeliad leaves. Females may carry 7– 10 eggs in the egg-brooding dorsal pouch. The advertisement call was described by Franz and Mello (2015), who identified the species as F. aff. fissilis .

Figures

FIG. 1.—Adult females of Fritziana mitus sp. nov. (A) without eggs on dorsum (holotype CFBH 39949) and (B) with eggs on dorsum (paratopotype MNRJ 90351). Both from the Parque Estadual da Serra do Tabuleiro, municipality of Santo Amaro da Imperatriz, state of Santa Catarina, Brazil.

FIG. 2.—Fritziana mitus sp. nov., holotype (CFBH 39949) from the Parque Estadual da Serra do Tabuleiro, municipality of Santo Amaro da Imperatriz, state of Santa Catarina, Brazil. (A) Dorsal and (B) lateral views of the head; (C) palmar view of the left hand; and (D) plantar view of the left foot.

FIG. 3.—Dorsal patterns of Fritziana mitus sp. nov. The most common pattern (A) CFBH 25723 and some variations, with an interorbital bar, are in (B) CFBH 12194 and (C) MZUSP 139225. Other possible patterns, without an interorbital bar, are in (D) CFBH 10008, (E) CFBH 19955, and (F) CFBH 24277. Arrows indicate skin crests that delimit the dorsal pouch of females without eggs on the dorsum. A color version of this figure is available online.

FIG. 4.—Tadpole of Fritziana mitus sp. nov., Stage 35 of Gosner (1960), from Bertioga, state of São Paulo, Brazil (lot CFBH 34437). (A) Lateral, (B) ventral, and (C) dorsal views (scale = 1 mm). A color version of this figure is available online.

FIG. 5.—Oral disc of the tadpole of Fritziana mitus sp. nov., Stage 35 of Gosner (1960), from Bertioga, state of São Paulo, Brazil (lot CFBH 34437). (A) Drawing and (B) photo (scale = 0.5 mm).

FIG. 6.—Bayesian tree for species in the genus Fritziana inferred from 16S ribosomal RNA gene fragments. Samples of Fritziana izecksohni used in the original description of that species are indicated in bold. Specimens bound by the square are those that served as the basis for the description of F. mitus sp. nov.; the asterisk (*) indicates a paratype included in the analyses. Scale indicates rate of base substitutions per site. See Appendices II and III for sample details.

FIG. 7.—Geographical distribution of Fritziana mitus sp. nov. The star and circles show the distribution of analyzed specimens (star = type locality in municipality of Santo Amaro da Imperatriz, in the state of Santa Catarina, Brazil [shaded area of inset]). The other markers show the type localities of F. fissilis and F. ulei (pentagon), Nova Friburgo; F. goeldii and F. izecksohni (triangle), Teresópolis; F. ohausi (square), Petrópolis, all in the state of Rio de Janeiro, and F. tonimi (hexagon), Santa Tereza, in the state of Espírito Santo. Green shading represents the remnants of the Atlantic Forest, Brazil. A color version of this figure is available online.

Tables

TABLE 1.—Mean ± 1 SD and range for measurements (mm) of male and female Fritziana mitus sp. nov., including the type series and additional specimens (see Appendix I). SVL = snout–vent length, HW = head width, HL = head length, AL = arm length, FAL = forearm length, HAL = hand length, THL = thigh length, TBL = tibia length, TL = tarsus length, FL = foot length, ED = eye diameter, TD = tympanum diameter, END = eye–nostril distance, IND = internarial distance, IOD = interorbital distance, DFIV = disc diameter of Finger IV, DTIV = disc diameter of Toe IV.

	Males (n = 26)		Females (n = 24)
Trait	Mean ± SD	Range	Mean ± SD	Range
SVL	19.97 ± 1.65	16.16–23.67	24.28 ± 2.47	17.43–28.35
HW	6.57 ± 0.63	5.26–7.82	8.05 ± 0.89	5.63–9.33
HL	7.24 ± 0.58	6.22–8.65	8.45 ± 0.86	6.43–9.92
AL	5.69 ± 0.37	4.88–6.44	6.70 ± 0.78	4.96–8.45
FAL	4.08 ± 0.35	3.33–4.88	4.83 ± 0.59	3.54–6.55
HAL	5.82 ± 0.54	4.35–6.89	6.75 ± 0.72	5.09–8.84
THL	9.47 ± 0.77	7.07–10.80	11.11 ± 1.08	8.09–13.77
TBL	10.68 ± 0.90	8.64–13.10	12.67 ± 1.11	9.45–15.27
TL	5.77 ± 0.48	4.66–7.11	6.81 ± 0.63	5.08–8.08
FL	8.75 ± 0.78	6.89–10.34	10.49 ± 1.27	7.48–14.80
IND	1.26 ± 0.13	1.05–1.60	1.46 ± 0.19	1.11–1.91
IOD	2.41 ± 0.46	0.62–3.46	2.95 ± 0.30	2.28–3.58
ED	2.67 ± 0.26	2.16–3.09	3.01 ± 0.34	2.34–3.64
END	2.21 ± 0.28	1.85–3.09	2.51 ± 0.27	1.85–3.02
TD	0.84 ± 0.13	0.62–1.11	0.97 ± 0.16	0.62–1.23
DFIV	0.97 ± 0.12	0.70–1.16	1.16 ± 0.17	0.87–1.50
DTIV	0.93 ± 0.12	0.65–1.19	1.12 ± 0.16	0.82–1.45