Ameerega boehmei, Lötters, Stefan, Schmitz, Andreas, Reichle, Steffen, Rödder, Dennis & Quennet, Verena, 2009

Lötters, Stefan, Schmitz, Andreas, Reichle, Steffen, Rödder, Dennis & Quennet, Verena, 2009, Another case of cryptic diversity in poison frogs (Dendrobatidae: Ameerega) — description of a new species from Bolivia, Zootaxa 2028, pp. 20-30 : 22-29

Ameerega boehmei sp. nov.

( Figs. 2–3 )

Dendrobates flavopictus (non Hylaplesia flavopicta A. Lutz, 1925 )— Gans 1960: 298.

Phyllobates pictus (non Hylaplesia picta Tschudi, 1838 ) — Silverstone, 1976: 39 (partim).

Epipedobates braccatus (non Dendrobates braccatus Steindachner, 1864 ) — Morales, 2001: 270. Ameerega flavopicta (non Hylaplesia flavopicta A. Lutz, 1925 ) — Lötters et al. 2007: 333 (partim).

Holotype. NKA 8469, male, Serranía de Santiago, roughly 6 km east of Santiago de Chiquitos (1819 ’ S, 5934 ’ W, ca. 800 m above sea level), Chiquitanía region, Provincia San Jos de Chiquitos, Departamento Santa Cruz, Bolivia, April 2002, V. Quennet leg.

Paratypes. NKA 8470-72, ZFMK 77442-444, males, same data as holotype. CAS 97762-63, CM 36155, LACM 44399, 60976, MCZ 29813-25, Serranía de Chochis, near El Portón (1860 ’ S, 6040 ’ W, ca. ca. 720 m above sea level), Chiquitanía region, Provincia San Jos de Chiquitos, Departamento Santa Cruz, Bolivia.

Diagnosis. The new species is assigned to the genus Ameerega (sensu Grant et al. 2006; Lötters et al. 2007) based on the following combination of characters: (1) dorsal skin slightly granular; (2) Finger I> Finger II when adpressed; (3) toe and finger webbing absent; (4) presence of bright flash marks and absence of ventrolateral line. Its specific diagnostic characters include: (5) adult mean size 27.57 mm 2.56 (19–35 mm, N = 46); (6) maxillary teeth present; (7) tympanum well visible; (8) black ground colour with bright yellow dorsolateral lines from snout to groin, bright yellow labial line continuous up to upper arm and bright yellow mid-dorsal spots and/or dots, commonly arranged in two parallel lines; (9) bright orange-red axillary, thigh (extending onto femur) and calf flash marks; (10) limbs brown with black markings or black with bright yellow markings; (11) ventral surfaces light grey to light brown with black marbling.

The new species is most similar to A. braccata (Steindachner, 1864) and A. flavopicta (A. Lutz, 1925) from Brazil, the only other members in the genus with bright mid-dorsal spots and/or dots, commonly arranged in two parallel lines. Ameerega boehmei shares with A. braccata characters 1–4, 6–11 and can be distinguished on the basis of adult size: 27.57 mm 2.56 (19–35 mm, N = 46) versus 20.19 mm 1.32 (18.3–21.3 mm, N = 9) in A. braccata ( Haddad & Martins 1994) . Also, in living A. braccata , lines and spots/dots are golden, yellow or white, while in A. boehmei they are always bright yellow. Furthermore, in A. braccata , limbs are brown with black markings, while in A. boehmei they are black with bright yellow markings. Moreover, A. braccata occasionally has brownish dorsal marbling which is always absent in the new species. Ameerega flavopicta shares with A. boehmei characters 1–9 and in part character 10; some individuals of A. boehmei have brown limbs with black markings (unlike in A. flavopicta ) but limbs in this species can also be black with bright yellow markings (like in A. flavopicta ). The two can be best differentiated by life colour pattern of the ventral surfaces: light grey to light brown with black marbling in A. boehmei versus yellowish white with occasional black marbling in A. flavopicta . As indicated below, the three species additionally differ in their sequences of a 564 bp (including gaps) fragment of the 16S mitochondrial rRNA gene. Ameerega boehmei , A. braccata and A. flavopicta can also be distinguished in advertisement call characteristics.

Ameerega picta (Tschudi, 1838) sensu stricto (including its junior synonym Dendrobates eucnemis Steindachner, 1864 ) from Bolivia, Peru and Brazil and a Guianan form of unclear taxonomic status (here provisionally treated as A. guayanensis Heatwole, Solano & Heatwole, 1965 ), are morphologically similar to A. boehmei . However, they both never develop bright mid-dorsal spots and/or dots ( Haddad & Martins 1994; Lötters et al. 2005, 2007).

The Amazon basin Ameerega trivittata (Spix, 1824) can have irregularly arranged bright dorsal markings. This species is larger than A. boehmei (adult male size> 40 mm) and lacks flash marks ( Silverstone 1976; Lötters et al. 2007).

Description of type series. Body slender, head narrower than body; snout in dorsal and lateral views rounded. Maxillary teeth present, vomerine teeth absent; choanae rounded; tongue more than three times as long as wide, free for about half its length. Nares not visible from dorsal view; canthus rostralis convex from tip of snout to nostril, straight from nostril to eye; loreal region vertical; horizontal eye diameter larger than distance from nostril to anterior corner of eye; tympanum visible, less than half eye size. Skin of dorsal surfaces slightly granular, ventral surfaces almost smooth. Toe webbing absent; relative length of toes: I <II <V <III <IV; metatarsal tubercles well developed, outer rounded, somewhat smaller than ovoid inner; rest of sole smooth; well developed subarticular tubercles at joints of all phalanges of foot. Finger webbing absent; relative length of fingers: IV = II <I <III, Finger I> Finger II when adpressed; metacarpal tubercles well developed, outer rounded, outer about three times the size of ovoid inner; rest of palm smooth; well developed subarticular tubercles at joints of all phalanges of hand.

For measurements and proportions of holotype and paratypes at NMK and ZFMK see Table 1 . In the field, females and males could not be distinguished by size; 46 adults measured had mean size 27.57 mm 2.56 (19–35 mm), with the largest specimen identified as an apparent female, however.

In preservative, the entire type series can be described as follows: dorsum black with greyish dorsolateral lines from snout to groin, commonly with mid-dorsal spots and/or dots arranged regularly (i.e. in two parallel lines) or irregularly; labial line continuous up to upper arm; small, pinkish spots above axillae, large, pinkish spots above thigh (extending onto femur) and small, pinkish calf flash marks; limbs greyish tan with black or black with greyish markings; ventral surfaces light grey to light brown with black marbling. For individual colour pattern details of the holotype see Figure 3 .

In life, A. boehmei type specimens at NMK and ZFMK had bright yellow dorsolateral and labial lines and mid-dorsal spots and/or dots; flash marks were bright orange-red; limbs were brown with black or black with bright yellow markings; ventral surfaces were light grey to light brown with black marbling; there was a bronze ring around the pupil. The 46 adults and six juveniles not collected coincided with life colour pattern descriptions given above. The number of dorsal spots and/or dots varied between 6 and 27, with juveniles apparently exhibiting less mid-dorsal spots and/or dots. Life colour pattern description given here coincides with that of Gans (1960). Figure 2 shows a typical specimen of the new species in life.

Advertisement call. Recordings of three Ameerega boehmei males were taken in the field (Serranía de Santiago). The advertisement can be characterized as a series of indistinctly pulsed, upward modulated notes as illustrated in Figure 4 A. For measurable call parameters and intraspecific variation see Table 2.

Foot length from tip of longest toe to proximal outer metatarsal tubercle 11.2 11.4 1.30 (9.9–13.8) Hand length from tip of longest finger to proximal outer metacarpal 6.4 6.6 0.93 (5.4–8.4) tubercle

The advertisement call of A. braccata (recorded at its type-locality, Chapada dos Guimarães, Mato Grosso, Brazil, L. Forti pers. comm.) differs from the new species in shorter mean note duration, higher note repetition rate, lower number of pulses per call and a higher maximum energy of the dominant frequency ( Table 2).

The advertisement call of A. flavopicta was described by Haddad & Martins (1994) based on recordings from Minas Gerais state, Brazil, and by Costa et al. (2006) who recorded this species in Goiás state, Brazil. In addition, original recordings from Goiás state are available on a commercial compact disc (Toledo, L.F., J.G.R. Giovanelli, L. O.M. Giasson, C.P.A. Prado, L.D. Guimaraes, R.P. Bastos & C.F.B.Haddad. 2007. Guia interativo dos anfíbios anuros do cerrado, campo rupestre & pantanal. Editoria neotrópica LTDA, Pinheiros, São Paulo). Figure 4 B illustrates each an oscillogram and an audiospectrogram of the last mentioned analysed by ourselves. The advertisement call of A. boehmei can be distinguished from all three available A. flavopicta vocalizations ( Table 2). In A. flavopicta , mean note duration is shorter (except for the Goiás state population studied by Costa et al. 2006), the mean number of notes per second is higher (except for the Minas Gerais state specimens studied by Haddad & Martins 1994), the number of pulses per note is distinctly higher, the fundamental frequency range and its maximal call energy is remarkably higher (data available for the Goiás state population only; Fig. 4 B) and the dominant frequency range is higher (even at the same temperature).

Several of the differences, such as note repetition rate, note duration, inter-note interval and dominant frequency range may be influenced by temperature and motivation of individuals, while the number of pulses per note is less dependent on such factors ( Narins et al. 2007). We therefore conclude that differences observed between A. boehmei , A. braccata and A. flavopicta reflect rather inter- than intraspecific variation.

A. boehmei A. braccata A. flavopicta

I II III L. Forti (pers. Haddad & Costa et al. Alto Paraíso, comm.) Martins (2006) Goiás state (1994)

DNA barcoding. Table 3 compares uncorrected p-distances of a 564 bp (including gaps) fragment of the 16S mitochondrial rRNA gene of Ameerega boehmei and other Ameerega species falling under the name A. picta sensu Silverstone (1976) . As perhaps expectable, lowest distance occurs between A. boehmei and A. flavopicta (ca. 2 %) while the new and other species differ at 2.7–5.1 %. Comparatively high genetic similarity of species as found between A. boehmei and A. flavopicta occurs among several other, well acknowledged Ameerega species, e.g. A. braccata and A. flavopicta or A. picta and A. yungicola (Table 3).

Lötters et al. (2005) reported even higher similarity (<2 %) among other, well distinguishable Ameerega species.

Distribution and life history. Ameerega boehmei is only known from the Serranías de Santiago and Chochis, isolated Precambrian sandstone massifs in the Chiquitanía region of Bolivia ( Fig. 1 ). Elevational records are from about 700–1200 m above sea level ( Gans 1960; pers. observ. on uncollected specimens). The general area is semi-arid and hot (ca. 50 % rel. humidity and 30°C during the day at 1 m above ground were common in March and April 2002; pers. observ.) with a rainy season from November to April. Natural vegetation includes semi-deciduous forest and 'cerrado' formation ( Fig. 2 ).

Frogs were found active during the day, with an activity peak from 05:00 to 11:00 AM, in non-forested areas in the vicinity of sandstone rocks, often situated near running water ( Fig. 2 ). Crevices are common and are frequently used by A. boehmei for hiding. Specimens can be found in crevices near ground up to more than 2 m above ground, especially during high temperatures and at night (cf. Gans 1960; pers. observ.). We measured the air temperature of three crevices on different occasions in April 2002, each for 24 hours. Temperatures were relatively constant at 21–25°C. Distances between rocks with frogs and the next evident water body was between one and more than 50 m airline. Calling activity was observed during morning hours from exposed portions of rocks. During our study period, three tadpoles in a temporary puddle and six subadults were found, suggesting reproduction takes place during the rainy season. Likewise, Gans (1960) observed nursery adults transporting tadpoles to ditches along a railway track in March.

Conservation status. The known distribution of Ameerega boehmei in the Serranías de Santiago and Chochis is part of the departmental reserve 'Valle de Tucavaca'. Within it some land-use alteration has been observed in some forests; however, areas in which A. boehmei occurs appear to be safe and in good shape. Applying IUCN Red List criteria (IUCN Red List of Threatened Species, 2001 Criteria & Categories (version 3.1.); http://www.iucnredlist.org/info/categories_criteria2001, accessed 1 July 2008), we consider this species to be of 'Least Concern' (LC).

Etymology. The specific name is a patronym for Wolfgang Böhme, in honour of his support of the scientific careers of all authors from early days on.

Figures

FIGURE 1. Known distributions of Ameerega braccata (magenta), A. flavopicta (orange) and the new species described here (red); map modified after Lötters et al. (2007).

FIGURE 2. From upper left to lower right: Ameerega braccata from Mato Grosso, Brazil (photo courtesy of M. Martins); A. flavopicta from Minas Gerais, Brazil (photo courtesy of M. Martins); flavopicta / braccata - like new species, A. boehmei, topotypic specimen not collected (photo by S. Reichle); aspect of landscape which is inhabited by A. boehmei; specimens mostly occur near sandstone which are often situated near running water (foreground) (photo by S. Reichle).

FIGURE 3. Ventral and dorsal views of preserved holotype (NKA 8469) of Ameerega boehmei (photos by S. Reichle).

FIGURE 4. Oscillogram and audiospectrogram of advertisement call of (A) Ameerega boehmei from the type locality (temperature during recording 23.5 ° C) and (B) A. flavopicta from Alto Paraíso, Goiás state, Brazil (temperature during recording 29 ° C)

Tables

TABLE 1. Measurements (mm) and proportions of Ameerega boehmei based on NKA and ZFMK type specimens. The mean is followed by the standard deviation and the range in parentheses.

	Holotype	Males (N = 7)
Size (snout-vent length) Head length from tip of snout to angle of jaws	25.5 7.8	25.5 2.53 (22.4–28.5) 7.8 0.46 (7.1–8.3)
Head width at angles of jaws	8.0	7.7 0.41 (6.9–8.0)
Interorbital distance Distance between nares	2.7 1.8	2.7 0.35 (2.1–3.1) 1.8 0.18 (1.6–2.0)
Distance from nostril to anterior corner of eye	2.5	2.3 0.26 (1.9–2.6)
Horizontal eye diameter Horizontal tympanum diameter	3.5 1.6	3.5 0.50 (2.8–4.2) 1.5 0.20 (1.2–1.7)
Tibia length	12.0	12.5 1.30 (11.0–14.6)