Corythomantis greeningi, Boulenger, 1896, Boulenger, 1896
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publication ID |
https://doi.org/10.11646/zootaxa.1686.1.4 |
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DOI |
https://doi.org/10.5281/zenodo.16043758 |
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persistent identifier |
https://treatment.plazi.org/id/6A1D0421-C178-5838-27CA-FEB0FBB7CE9C |
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treatment provided by |
Felipe |
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scientific name |
Corythomantis greeningi |
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Adult males of Corythomantis greeningi from São José Mountain were considerably smaller (SVL = 50.4 ± 7.3 mm, n = 7) than those of Lages (SVL = 75.1 ±6.2, n = 4). However, there were no other conspicuous differences.
External morphology of the tadpole. Tadpoles from Serra São José are smaller than Lages ( Table 1 View TABLE 1 ). Both examined population show oval body in dorsal view and slightly depressed in profile ( Figure 2 View FIGURE 2 ); body length approximately 36% of total length; body approximately 1.4 times wider than tall; snout rounded and downward protruding in profile; eyes dorsally oriented, interorbital distance approximately 3 times the eye diameter, and 1.5 wider than internostril distance; nostrils oval, dorsolaterally located, closer to the eyes than to the snout, and directed anterolaterally; spiracle single, short, sinistral, located at the middle third and below the midline of the body with opening slightly narrower than the basal region, directed upward; vent tube medial and attached to the ventral fin; tail musculature tapering off to pointed tip; tail muscle width around 35% of body width; dorsal fin originating at the end of the body, outline undulated, maximum height at mid point, ventral fin slightly narrower than dorsal fin ( Figure 2a and 2b View FIGURE 2 ); oral disc anteroventral, approximately 0.8 times the body width ( Figure 2c View FIGURE 2 ), not emarginated; dark labial teeth, labial tooth row formula (LTRF) 5– 6(1)/5–8 ( Figure 2d View FIGURE 2 ); one row of marginal papillae around the oral disc, without gap, papillae on the lower labium smaller than papillae on the upper labium; wide jaw sheaths, finely serrated, keratinized non-serrate lateral processes located at the extremities of the upper jaw sheath, upper jaw sheath with a non-serrate medial projection emerging bellow the serrated portion of the jaw; lower jaw V-open shaped.
Colour in formalin as follows. Body and musculature of the tail contrasting from beige to pale brown; dorsal and lateral surfaces with black mottling, conferring a darker appearance; belly cream, without mottling; intestines dark brown, conspicuous laterally and ventrally; tail musculature more pigmented than fins; dorsal fin more pigmented than the ventral; beak black.
Advertisement call. The advertisement call is one pulsed note with amplitude and frequency modulation. We could distinguish two different note parts, called here part A and part B ( Figure 3A–C View FIGURE 3 ). The note begins with a long series of pulses with low amplitude and no frequency modulation (part A). Amplitude rises slowly to the end of the call and falls abruptly after the amplitude peak. Most energy is concentrated at the end of the call in two of the four observed harmonics (part B). Dominant frequency ranged from 0.73–1.46 kHz and from 0.64–1.24 kHz in Lages and São José Mountain respectively. Part A is longer with more pulses and lower pulse rate (pulses/s) than part B ( Table 2 View TABLE 2 ). The dominant frequency of part B always is a little higher than the part A ( Table 2 View TABLE 2 ). Advertisement call structure is similar in the two populations studied. Acoustic parameters differ slightly ( Table 2 View TABLE 2 ).
Discussion
Jared et al. (1999) published a sonogram of the territorial call of Corythomantis greeningi without descriptive and quantitative analysis. These authors associated that vocalization with territorial call because they observed fights between males. However, the authors did not specify if the recorded male was the fighter male. The sonogram published shows five calls with similar characteristics to those analyzed herein. Nevertheless, we did not observe fights or other behaviour that might indicate additional kind of interactions between individuals. Because Jared et al. (1999) did not present the acoustic parameters values, it is difficult to precise if their recordings of C. greeningi represented another type of call.
Besides the size difference in male adult size, the advertisement call and tadpole morphology are so similar that they could not be used to separate the normal and the dwarf populations as different species. Although the two populations of C. greeningi had tadpoles also with different sizes ( Table 1 View TABLE 1 ), the general morphology of the body and characteristics of oral disc were the same. The advertisement call shows the same structure with slight differences in the averages of the parameter measurements (Table 3), but all of them are in the range of standard deviation. Because the low number of individuals recorded from the two populations, the differences obtained in the advertisement calls do not permit a secure conclusion to separate these populations in two species.
Dwarf species evolution has been associated with competition pressures, normally competition to some essential resource as food, shelter or territory ( Kishdi & Geritz 2001). Although Corythomantis greeningi is adapted to xeric environments, São José Mountain is an environment that suffered great changes by farm system. The native vegetation was removed and the cattle use the water of many points along of the rivers. This factor might be interfering on both quantity/quality of shelters available to adults and tadpoles of C. greeningi and on abundance of microorganisms living in the water of the rivers that could be important items to tadpole diet. The decreasing availability of water resources may be favouring the survival of smaller morphs. However, other factors could explain this situation as well (e.g. accelerated metamorphosis to avoid death by desiccation in smaller pools).
Remarks
Although the oviposition of Corythomantis greeningi can occur in lentic water ponds ( Jared et al. 1999) formed along temporary shallow rivers, the tadpoles frequently are found clasping on the rocky river bed ( Figure 1b View FIGURE 1 ) and swimming against the current (first author’s personal observation). Corythomantis greeningi tadpoles have a depressed body, oral disc with a complete uniserial marginal papillae, LTRF 5–6(1)/5–8 and show a scouring surface on the front face of the upper sheath just proximal to the serrated edge (similar to Isthmohyla pictipes, Altig & McDiarmid 1999 ), corresponding with the typical morphology for suctorial larvae inhabiting benthonic fast-water habitats ( McDiarmid & Altig 1999).
Tadpoles of other casque-head species inhabit either lotic or lentic water, showing varied body morphology and an oral disc, whose morphology might be explained by different habitat use (see Wogel et al. 2006 and Pimenta & Canedo 2007 for comparative data and discussion). Known tadpoles of casque-head species of Aparasphenodon , Osteocephalus , Trachycephalus and Itapotihyla have a gap on upper lip papillae rows and the number of anterior tooth rows is normally two or three and posterior tooth rows varying from four to 8 rows ( Wogel et al. 2006; Pimenta & Canedo 2007). The presence of four posterior labial tooth rows, at least, is indicated as a putative morphological synapomorphy of the tribe Lophiohylini confirming the phyllogenetic position of C. greeningi in this tribe as proposed in Faivovich et al. (2005). However, we agree with Altig (2006) that many changes in the oral disc represent morphological adaptations associated with specific modes of feeding constrained by a large and poorly understood phylogenetic component and that less plastic structures than mouthparts will prove to be the most phylogenetically informative.
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