Myersiohyla liliae, (KOK, 2006), 2019

MYERSIOHYLA LILIAE (KOK, 2006) View in CoL COMB. NOV.

Hypsiboas liliae Kok, 2006: 192 , figs 1–4. Hypsiboas liliae Kok — Kok & Kalamandeen, 2008:

172, fig. 112. — Faivovich, McDiarmid & Myers,

2013: 51. Boana liliae — Dubois, 2017: 28.

Diagnosis: Myersiohyla liliae can be diagnosed by the following combination of characters: (1) small snout–vent length in males (SVL 32.5–37.1 mm; females unknown); (2) granular skin on dorsum; (3) presence of an ulnar fold on forearm; (4) single, dark-coloured nuptial pad on Finger II, at the level of the subarticular tubercle between Metacarpal II and Proximal Phalanx; (5) overall coloration green with melanophores homogeneously distributed on the dorsum, ventral surfaces blue, translucent in the central portion of abdomen; in preservative all surfaces become whitish; (6) white parietal peritoneum; (7) advertisement call composed of a sequence of notes that increase in intensity and rate, as the interval between notes diminishes; (8) dominant frequency of the notes 3.24–3.94 kHz (Kok, 2006).

Characterization: See Kok (2006) for a thorough description of the type series.

Comparison with other species of Myersiohyla : The SVL in males of M. liliae (32.5–37.1 mm; Kok, 2006) distinguishes it from all other species of the genus, which are larger (combined SVL of males of M. aromatica , M. chamaeleo , M. inparquesi , M. loveridgei and M. neblinaria 42–52.3 mm; Rivero, 1961, 1972; Ayarzagüena & Señaris, 1994; Faivovich et al. 2013). The dorsal granular skin distinguishes M. liliae from all the other species of Myersiohyla (dorsal skin smooth; Rivero, 1961, 1972; Ayarzagüena & Señaris, 1994; Kok, 2006; Faivovich et al., 2013). The presence of an ulnar fold on the forearm distinguishes M. liliae from M. chamaeleo (ulnar fold absent in this species; Kok, 2006; Faivovich et al., 2013). Whereas M. liliae has a single nuptial pad on Finger II ( Fig. 6D), M. aromatica , M. chamaeleo and M. loveridgei have two pads ( Ayarzagüena & Señaris, 1994; Kok, 2006; Faivovich et al., 2013), and M. inparquesi and M. neblinaria have a single, larger nuptial pad, which covers dorsally the prepollex and Finger II ( Ayarzagüena & Señaris, 1994; Faivovich et al., 2013). The only other species reported to present an overall greenish coloration is M. chamaeleo , which also has stellated melanophores ( Faivovich et al., 2013). The melanophores in M. liliae are less concentrated and more homogeneously distributed than in M. chamaeleo ( Fig. 6A, B; compare with figs 4 and 7 in Faivovich et al., 2013). The remaining species of Myersiohyla have a brownish dorsum that can be marbled with copper ( M. aromatica ), or darker hues ( M. loveridgei ), or have thin black reticulations ( M. inparquesi ), or spots ( M. neblinaria ; Rivero, 1961, 1972; Ayarzagüena & Señaris, 1994; Faivovich et al., 2013). The white peritoneum is shared only with M. chamaeleo ; M. neblinaria has a translucent peritoneum ( Faivovich et al., 2013). This character state is unknown in the other species of this genus. Finally, species of Myersiohyla with described vocalizations (all but M. loveridgei ) have calls with a long series of repeated notes; however, the call of M. liliae has an increase in both intensity and rate of the call, while M. aromatica , M. chamaeleo , M. inparquesi , and M. neblinaria have a call with a constant interval between notes, and constant intensity ( Ayarzagüena & Señaris, 1994; Kok, 2006; Faivovich et al., 2013). The dominant frequency of the advertisement call of M. liliae (3.24– 3.94 kHz; Kok, 2006) is higher than in the other Mysersiohyla species for which the advertisement call is known (combined values of dominant frequency of M. aromatica , M. chamaeleo , M. inparquesi and M. neblinaria 1.52–2.2 kHz; Ayarzagüena & Señaris, 1994; Faivovich et al., 2013).

Natural history: Specimens of Myersiohyla liliae were collected calling from water-filled phytotelms of the bromeliad Brocchinia micrantha ( Baker, 1879) , but in a nearby locality males were heard calling from high elevation in trees close to a field of bromeliads of the same species (Kok, 2006). Whether the species actually reproduces in phytotelms remains unknown. Although the exact place of oviposition is unknown in the other species of Myersiohyla , tadpoles of four species have been collected in streams ( Ayarzagüena & Señaris, 1994; Faivovich et al., 2013). Myersiohyla aromatica and M. chamaeleo have been reported to call from bromeliads, close to streams, and M.neblinaria at least uses bromeliads for day retreat (Ayarazagüena & Señaris, 1994; Faivovich et al., 2013). Five species of Myersiohyla are known to perch on vegetation around streams in the flat-topped tepuis in southern Venezuela, at elevations above 900 m a.s.l. ( Rivero, 1961, 1972; Ayarzagüena & Señaris, 1994; Faivovich et al., 2013). Myersiohyla liliae , however, is an inhabitant of primary forests at lower elevations (400– 550 m a.s.l.; Kok, 2006). There are observations of release of strong odors by M. aromatica and M. inparquesi ( Ayarzagüena & Señaris, 1994) ; none was noticed by the collectors in M. liliae (PJR Kok and BP Noonan, pers. obs.). See Kok (2006) and Kok & Kalamandeen (2008) for more information.

Distribution: This species is known only in western Guyana, where it has been collected in the Potaro-Siparuni District (the Kaieteur Plateau), and in the Cuyuni-Mazaruni District (Imbaimadai). Kok (in Kok & Kalamandeen, 2008) reported hearing calls from this species on the slopes of the Maringma-tepui at the Guyana – Brazil border, and suggested that the species is probably widespread in the Pakaraima (also spelled Pacaraima) Mountains of Guyana.

Remarks: In the original description of Boana liliae, Kok (2006) tentatively assigned the new species to Boana (as Hypsiboas ) and to the B. punctata group, on the basis of its similarity with B. cinerascens , although stressing that there were no putative synapomorphies for this association. Our results, instead, recover a strongly supported sistertaxon relationship with Myersiohyla chamaeleo , supporting the association of that species with the genus Myersiohyla . This placement, based on our molecular data, actually implies no incongruence with phenotypic evidence.

Kok (2006) characterized Boana liliae on the basis of the combination of 22 characters: (1) medium size (SVL 32.5–37.1 mm in adult males; females unknown); (2) skin of dorsum and belly thickly granular; (3) body slender; (4) head slightly wider than long, wider than body; (5) snout truncate in dorsal view and slightly protruding in lateral view, with strongly protuberant nostrils; (6) eyes large, prominent, palpebral membrane lacking reticulations; (7) tympanum large, round, approximately half the horizontal diameter of the eye; (8) supratympanic fold strongly visible, not or feebly obscuring the upper margin of the tympanum; (9) limbs long and slender; (10) axillary membrane absent; (11) subarticular tubercles on fingers single; (12) prepollex enlarged, not modified as a projecting spine; (13) nuptial pads present in males; (14) mental glands in males, small; (15) hands about one-fifth webbed, feet about four-fifths webbed; (16) ulnar fold distinct; (17) inner tarsal fold weak, tarsal tubercles absent; (18) heel tubercles and calcar absent; (19) cloacal sheath absent or very short; (20) in life, dorsal surfaces bright green to bright yellowish green during the day, greenish brown at night, ventral surfaces blue, translucent in the central portion of abdomen, iris silver with black periphery during the day, bronze at night; in preservative all surfaces become whitish; (21) peritoneum white; (22) advertisement call consisting of a long series of loud percussive notes gradually increasing in speed and loudness (call length about 60 s, up to seven notes per second).

Most of these characters would allow an association with many species in most genera of Cophomantini . A few of these, however, require comment. An enlarged prepollex not modified as a projecting spine [Character (Ch.) 12] is shared with Nesorohyla , Myersiohyla , Hyloscirtus (except H. condor , H. diabolus Rivera-Correa, García-Burneo & Grant, 2016 and H. tapichalaca ), Aplastodiscus and some species of the Boana semilineata group [ B. diabolica ( Fouquet, Martinez, Zeidler, Courtois, Gaucher, Blanc, Lima, Souza, Rodrigues & Kok, 2016), B. geographica ( Spix, 1824) , B. hutchinsi ( Pyburn & Hall, 1984) and B. semilineata ( Spix, 1824) ; Faivovich et al., 2006; Fouquet et al., 2016]. Nuptial pads (Ch.13) occur in Myersiohyla , Nesorohyla , one species of Aplastodiscus , some species of Bokermannohyla , Hyloscirtus and the Boana semilineata species group ( Lutz, 1950; Ayarzagüena & Señaris, 1994; Faivovich et al., 2006, 2013; Leite, Pezzuti & Drummond, 2011; Coloma et al., 2012; Rivera-Correa & Faivovich, 2013). The presence of a mental gland in males (Ch. 14) is shared with several species of Boana , and also many species of Aplastodiscus , Bokermannohyla , Hyloscirtus and Myersiohyla (see Brunetti et al., 2014). The re-examination of the type series of M. liliae shows the occurrence of several glandular acini in the mental region ( Fig. 6C; IRSNB 1968). Cumuli of glandular acini were also found in other parts of the body, such as the margins of fingers and toes ( Fig. 6B; IRSNB 1968): a histological analysis is required to corroborate whether these skin glands are sexually dimorphic. White peritonea (Ch. 21), the presence of iridophores on parietal or visceral peritonea, are reported in Aplastodiscus , some species of Boana of the B. benitezi , B. faber , B. pellucens , B. pulchella and B. punctata groups, the Hyloscirtus bogotensis group and Myersiohyla chamaeleo ( Duellman, 1971; Lutz, 1973; Hoogmoed, 1979; Ruiz-Carranza & Lynch, 1991; Garcia, 2003; Faivovich et al., 2005, 2006, 2013; Berneck et al., 2016). The advertisement call composed of a long series of notes (Ch. 22), as discussed above, is shared with all species of Myersiohyla for which calls have been described. In fact, to our knowledge, in Boana a similar call structure is present only in B. faber ( Wied-Neuwied, 1821) , B. pellucens ( Werner, 1901) and B. boans ( Linnaeus, 1758) ( B. faber , B. pellucens , and B. semilineata groups, respectively; Martins & Haddad, 1988; Duellman, 2005).

Our specimens of M. liliae are from the Kaieteur Plateau (Potaro-Siparuni District, Guyana), and from Imbaimadai (Cuyuni-Mazaruni District, Guyana). The two localities are 110 km distant from each other, and the specimens have p -distances in 16S of 2.2–2.3% ( Table 1). This is a considerable molecular intraspecific variation for the ribosomal gene 16S (see Fouquet et al., 2007), and suggests that variation in this species requires an assessment.