Chiasmocleis bassleri Dunn, 1949

Peloso, Pedro L. V., Sturaro, Marcelo José, Forlani, Mauricio C., Gaucher, Philippe, Motta, Ana Paula & Wheeler, Ward C., 2014, Phylogeny, Taxonomic Revision, And Character Evolution Of The Genera Chiasmocleis And Syncope (Anura, Microhylidae) In Amazonia, With Descriptions Of Three New Species, Bulletin of the American Museum of Natural History 2014 (386), pp. 1-1 : 37-42

Chiasmocleis bassleri Dunn, 1949 Figures 22–23 , plate 4

Syncope bassleri: ( de Sá et al., 2012) .

HOLOTYPE (fig. 22): AMNH 42699 ; poorly preserved, portions of limbs destroyed, and color completely faded.

TYPE LOCALITY: Type locality given by Dunn (1949) as ‘‘Río Utoquinia to Río Tapiche, Peru (near the Brazilian border).’’

Peloso and Sturaro (2008) considered the type locality of Chiasmocleis bassleri as ‘‘vague.’’ Despite that, Rodrigues et al. (2011) gave an ‘‘approximate’’ coordinate for the type locality of C. bassleri , based on unclear arguments. In an attempt to solve this issue, we revisited Harvey Bassler’s field notes (deposited at the AMNH) and several hydrographic maps of eastern Peru.

From the field notes, it seems that the holotype ( AMNH 42699) was collected at the region where the Río Utoquinia would meet the Río Tapiche. However, from the maps we analyzed, it is not clear whether there is a water connection between the rivers. It is possible that minor waterways are present, thus providing a connection point between the rivers, but it is also possible that the only connection is by land. Regardless, this putative connection must be somewhere near the borders of departamentos of Ucayali and Loreto (both in Peru) and the state of Acre ( Brazil)—this region being roughly 120 km east of the city of Contamana, Peru, and 140 km west of Cruzeiro do Sul, Brazil. Dunn (1949) likely used the position of the Utoquinia and Tapiche to draw his map ( Dunn, 1949: fig. 4). The locality shown in Rodrigues et al.’s map ( Rodrigues et al., 2011: fig. 2) is, however, clearly far from the one presented by Dunn (1949: fig. 4) and certainly does not correspond to any point along the course of either the Río Tapiche or the Río Utoquinia. Coordinates given by Rodrigues et al. (2011) are ca. 450 km southeast of the locality where the distance between the Utoquinia and the Tapiche is at its minimum. After examination of maps and satellite images, we use the following coordinates as a proxy for the type locality of C. bassleri (07 ° 329300S / 73 ° 599350W: see fig. 25). 9

DIAGNOSIS: A medium-sized species for the genus; SVL in males 19.2–22.1 mm (N 5

9 Coordinates taken from direct observation of satellite images in the interactive software Google Earth, release 6.2.2 for Mac (Google Inc., 2012).

11), in females 21.2–28.8 mm (N 5 20). Body ovoid to elongate; head triangular; snout rounded in dorsal and lateral views. Four distinctive fingers; FI may be reduced in some specimens, but always clearly visible; tubercle on FI may be absent or present; subarticular tubercles present on all remaining fingers; adpressed FI never extends beyond the distal margin of subarticular tubercle of FII; adpressed FIV does not reach distal tubercle of FIII; palmar tubercles present, not divided; relative finger lengths I,II,IV,III. Five distinctive toes present, first may be much reduced; toes may be slightly fringed; toes not webbed; TI lacks tubercle; adpressed TI does not touch subarticular tubercle of TII; adpressed TV does not touch or reaches only to the middle of the middle subarticular tubercle of TIV (touches in the holotype) ; TII–IV with terminal discs, usually more developed in females, but also present in males; relative toe lengths I,II, V,III,IV. An inguinal blotch, variable in

TABLE 6 Uncorrected pairwise distances between 16S sequences of Chiasmocleis avilapiresae

shape, is always present. There is usually a marked contrast in color pattern between the dorsum and the venter that can be delimited by a split stripe.

VARIATION: We have found a high degree of variation in external characters of Chiasmocleis bassleri , especially in color pattern.

The original description reports a ‘‘belly white with five large circular black spots’’ ( Dunn 1949: 9). We have examined sympatric specimens that vary in spot counts, from just a couple to several (over five) well-defined circular spots (see, for example, fig. 23A). Some specimens do not have circular spots, but show elongated stains or, sometimes, a reticulated pattern (fig. 23F; this pattern is common in some specimens from Amazonas and Mato Grosso, Brazil, but is also present in some specimens from Ecuador).

Chest and throat usually consist of dark vermiculations against a light background (fig. 23A, B), but in some specimens the throat is uniformly dark colored, especially in males (fig. 23C, E–F). Few specimens show a

18.5 mm.

uniform pattern (whitish with black spots or stains) over the entire ventral surface (fig. 23D); this pattern is common in specimens from Peru. There is also extensive variation in length ratios between fingers and toes, especially length of FI, FIII/FIV ratio, length of TI, and TIV/TV ratio.

Color in life varies strikingly among specimens (pl. 4), but data are limited and prevent a detailed analysis of geographic variation. Dorsum can have a uniform color pattern, varying between tones of black, dark brown, purple, reddish, and pink. Several specimens may show blotches on the dorsum, usually lighter than the dorsum and varying between shades of red, orange, green, yellow, and pinkish. A specimen from Vaupés, Colombia, shows a bizarre dorsal pattern, with the left side dark reddish brown and the right side light cream with dark brown mottling (pl. 4G).

Most specimens show a well-marked differentiation between dorsal and ventral pattern, evidenced by a split stripe. In some specimens, the stripe is wide and black, extending from the posterior corner of the eye to the inguinal region (pl. 4B). The split is, however, absent in a few specimens (pl. 4D), but we found no clear pattern of geographical variation in this character. Sympatric specimens can show the absence or presence of the split (e.g., in Porto Walter, Acre, Brazil).

CALL AND TADPOLES: The advertisement call of C. bassleri has been previously described by Santana et al. (2009). The description here is based on the combined calls of three specimens from different populations, including a reanalysis of Santana et al.’s (2009) recording. Acoustic parameters for each individual call are listed in table 2. The call is composed of a fast, repetitive series of multipulsed notes (mean 5.2 ± 1.2 pulses per note, 2–16, N 5 764), emitted at a rate of 568.2 notes/min. Mean note duration 53.3 ± 11.1 ms (15.0–163.0, N 5 786) and mean interval between notes 49.0 ± 26.3 ms (11.0– 302.0, N 5 783). Mean dominant frequency was 2747.0 ± 145.8 Hz (2584–3125, N 5 786). Pulse duration was 6.9 ± 1.6 ms (4.0–11.0, N 5 368). A call from Rio Madeira, Rondônia, Brazil, is illustrated in figure 24.

Tadpoles are unknown.

REMARKS: The phylogenetic position of Chiasmocleis bassleri , given our results, is strikingly distinct from that found by de Sá et al. (2012), represented in his analysis by a single specimen from Loreto, Peru, also included here. We have included several samples of C. bassleri from throughout its distribution in the phylogenetic analysis, and although two well-supported clades were found, we did not find any phenotypic evidence to diagnose the clades as separate taxa. The levels of genetic distance within C. bassleri are generally low (0–6.8 %). Genetic distances between all specimens of C. bassleri included in the phylogenetic analysis are given in table 7.

DISTRIBUTION (fig. 25): Distributed in western Brazil (Acre, Amazonas, Mato Grosso, Pará, and Rondônia), eastern and northern Peru, southwest Colombia, and Ecuador. Icochea et al. (2004) presented a much wider distribution for the species in Peru, and mention the occurrence of the species in Bolivia.

Figures

Fig. 22. Holotype of Chiasmocleis bassleri (AMNH 42699) in (A) dorsal, and (B) ventral views. SVL 5

Fig. 23. Variation of ventral color pattern in Chiasmocleis bassleri. (A) Parque Nacional da Serra do Divisor, Acre, Brazil (UFAC-RB 1611). (B) Via Tarapacá, Letícia, Amazonas, Colombia (ICN 50249). (C) Porto Walter, Acre, Brazil (OMNH 34829). (D) Rio Curanja, Balta, Ucayali, Peru (KU 197036). (E) Floresta Nacional do Pau-Rosa, Rio Paraconi, Maués, Amazonas, Brazil (MPEG 27766). (F) Aripuanã, Mato Grosso, Brazil (UFMT 7136). Not to scale.