Adenomera diptyx
Creators: name: Zaracho, Víctor H.
name: Lavilla, Esteban O.
name: Carvalho, Thiago R.
name: Motte, Martha
name: Basso, Néstor G.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Leptodactylidae
Adenomera
Adenomera diptyx

description: Adenomera diptyx (Boettger, 1885), redescription
Figs 3–6; Tables 2–3
Diagnosis
Adenomera diptyx is recognized within Adenomera by the following combination of character states: (1) body slender; (2) medium size (adult male SVL = 18.2–23.1 mm); (3) a long vertebral pin stripe, extending from the interorbital region to the vent;(4) a distinctive interorbital bar; (5) toe tips unexpanded, tending to a tapered point; (6) antebrachial tubercle absent; (7) single-note advertisement call; (8) call notes formed by incomplete pulses; (9) short note duration (28–49 ms); (10) high note repetition rate (176–299 per minute); and (11) low pulse number (2–6 per note).
Type material
Lectotype PARAGUAY • ♂ (Fig. 3A–C); “ Paraguay, Amer. Merid ” (exact locality unknown); 1985; H.R. Rhode leg.; BMNH 1947.2.17.47.
Paralectotypes (3 specimens examined; one specimen not examined, possibly lost) PARAGUAY • 1 spec.; same collection data as for lectotype; BMNH 1947.2.17.48 (Fig. 3D–E) • 1 spec.; same collection data as for lectotype; ZMB 10595 • 1 spec.; same collection data as for lectotype; NMW 4475 (Fig. 4).
Material examined
PARAGUAY – Amambay • 6 ♀♀; Parque Nacional Cerro Corá; 22°39′56″ S, 56°00′24″ W; MNHNP 0416, 0429, 1221, 4420, 4492, 5709 • 1 ♀; same collection data as for preceding; UNNEC 13937 • 2 ♂♂; same collection data as for preceding; MNHNP 0418, 0438 • 1 ♂; same collection data as for preceding; UNNEC 13936. – Cordillera • 2 ♀♀; Piribebuy; 25°28′06″ S, 57°02′33″ W; CZCEN 0646, 0647, 0650 • 8 ♂♂; same collection data as for preceding; CZCEN 0640 to 0645, 0648, 0649.
Redescription of A. diptyx
The original description of the syntypes of Adenomera diptyx by Boettger (1885) included the main morphological characters of the species, some of which were later highlighted by Heyer (1973) when he designated the species’ lectotype. The following re-description is based on all the specimens seen and examined by us, including specimens recently collected and linked to calls and DNA sequences.
Morphology
Body medium, slender (SVL = 18.2–25.9 mm); head nearly as broad as long (HW/HL = 1.06). Measurements of males and females are given in Table 2. Sexual dimorphism in head shape: males with snout sub-elliptical dorsally and acuminate laterally due to the presence of a developed, shovel-shaped, fleshy ridge, and females with snout rounded laterally, without a fleshy ridge (Fig. 5D). Canthus rostralis round, indistinct; loreal region slightly concave; eye dorsolateral, its diameter about 34% of head length; pupil horizontal, elliptical; palpebral membrane translucent, bordered in its upper edge by a black streak; tympanum distinct, its diameter about 47% eye diameter; tympanic membrane translucent; supratympanic fold well developed, extended from eye to arm insertion; nostrils anterolateral, closer to the tip of the snout than to the eye; internarial distance about 28% head width; postcommissural gland oval; lower lip with a medial projection that fits into a notch in the upper; tongue ovoid; males with vocal sac subgular with a fold parallel to jaw extending to forearm; maxillary and premaxillary teeth present; vomerine teeth present, located posterior to and between choanae, arranged in straight transverse rows. Dorsum glandular; with numerous, small, white-tipped tubercles posteriorly; two pairs (dorsal and lateral) of glandular rows starting behind the eyes and running towards the posterior part of dorsum; ventral surface smooth, except on thigh, areolate; pectoral fold absent, lateral and abdominal folds distinct; axillary gland small; arm short and robust, finger tips rounded, not expanded; relative finger length IV <I = II <III; inner metacarpal tubercle oval and ½ to ⅔ smaller than the outer metacarpal tubercle, circular; palmar tubercles present; subarticular tubercles prominent, rounded, the one on the thumb remarkably larger than the others; shank slightly longer than thigh; thigh length about 41% SVL; relative toe length I <II <V <III <IV, with rounded tips, neither expanded nor flattened (character state A); toes without webbing or lateral fringing; metatarsal tubercles oval, the outer smaller than the inner; inner tarsal fold distinct, with a single row of small, white-tipped tubercles on the edge, running about two thirds length of the tarsus; dorsal surface of the shank and ventral surface of the heel and sole of foot with numerous, small, white-tipped tubercles; most specimens with a paracloacal gland circular on each side of the vent.
Coloration
In life (Fig. 5G–H), dorsum medium brown with dark brown blotches; yellowish vertebral pinstripe in most specimens, sometimes interrupted anteriorly, continuous and broader posteriorly. Brown spot pattern on the head, defined by an anterior interorbital bar, a medial X-shaped spot, and a lateral oblique postorbital spot. Canthus rostralis highlighted by a dark brown band. Posterior part of the supratympanic fold and border of the upper eyelids highlighted in dark brown. Dorsal glandular row highlighted by coloration dark brown and cream. Upper surface of the arm light brown, with irregular spots; forearm with darker cross-bars. Upper surface of the thigh and shank light brown, in most with distinct, dark cross-bars on the shank. Posterior surface of the thigh with distinct darker blotches of poorly outlined borders. Dorsal surface of the shank-heel articulation cream-colored. Venter grayish white; in males lateral fold of the vocal sac dark brown. In preservative, color patterns similar to those described for the specimen in life, except for a duller coloration.
Variation
Number of small white-tipped tubercles highly variable, absent on the dorsal surface of the body in some specimens; paracloacal gland poorly defined in some specimens, only with a light-colored, small spot, or even absent. Lateral and abdominal folds indistinct occasionally. Palmar tubercles variable in number. Dorsal and lateral glandular rows sometimes unclear, but most are formed by few or several segments.
Vertebral pinstripe of variable length: from vent to the interorbital or inter-scapular region (long) or restricted to the pelvic region (short); indistinct in two specimens of 31 analyzed specimens (Fig. 6). Number, size, and distribution of the dark marks on the dorsum are quite variable, as well as the contrast between the background color and that of the marks. Glandular rows are highlighted by a single color or a combination of cream and dark color shades. Dark cross-bars on the dorsal surface of limbs are variable in number, in some specimens appear as spots with variable size and are distributed irregularly. The coloration of the paracloacal gland varies from cream-colored, dark-colored, or a combination of both. A few individuals have a dark-colored pigmentation at the base of the lower lip, coinciding with the vocal sac (Fig. 6).
Sexual dimorphism evident in head shape (see above), presence of a subgular vocal sac with distinct folds lateral to the jaw and extending to the forearm, highlighted by dark coloration in males, and females slightly larger than males, averaging 22.1 mm SVL in females and 20.8 mm SVL in males (Table 2).
Comparisons with congeners
Adenomera diptyx is distinguished from all congeners, except A. martinezi (Bokermann, 1956) and A. saci Carvalho & Giaretta, 2013, by its slender body, as opposed to the generally robust body of its congeners, including the morphologically similar but allopatric A. bokermanni (Heyer, 1973), A. coca (Angulo & Reichle, 2008), A. hylaedactyla, and A. thomei (Almeida & Angulo, 2006). The body size of A. diptyx (male SVL = 18.2–23.1 mm) differs from that of large-sized species of the genus, especially A. glauciae Carvalho, Simões, Gagliardi-Urrutia, Rojas-Runjaic, Haddad & Castroviejo-Fisher, 2020 (male SVL = 27.6–30.4 mm) and A. lutzi Heyer, 1975 (male SVL = 27.5–33.5 mm). Adenomera diptyx is also distinguished from all congeners, except A. martinezi and A. saci, by having a long vertebral pinstripe extending from the interorbital region to the vent, which is absent or rarely present in other species of Adenomera. Adenomera martinezi and A. saci have a complete pinstripe, extending from the tip of the snout. Adenomera diptyx is also distinguished from A. martinezi and A. saci by the presence of an interorbital bar and the absence of longitudinal rows of black spots on the dorsum (Carvalho & Giaretta 2013b). Adenomera diptyx has toe tips unexpanded with a tapered point (character state A), whereas the following 14 species have moderately to fully expanded toe tips (states C–D, i.e., swollen, knob-shaped toe tips and toe discs, respectively): A. ajurauna (Berneck, Costa & Garcia, 2008), A. amicorum Carvalho, Moraes, Lima, Fouquet, Peloso, Pavan, Drummond, Rodrigues, Giaretta, Gordo, Neckel-Oliveira & Haddad, 2021, A. andreae (Müller, 1923), A. chicomendesi Carvalho, Angulo, Kokubum, Barrera, Souza, Haddad & Giaretta, 2019, A. engelsi Kwet, Steiner & Zillikens, 2009, A. gridipappi Carvalho et al., 2021, A. guarayo Carvalho, Angulo, Barrera, Aguilar-Puntriano & Haddad, 2020, A. heyeri Boistel, Massary & Angulo, 2006, A. inopinata Carvalho et al. 2021, A. lutzi, A. marmorata, A. nana (Müller, 1922), A. simonstuarti (Angulo & Icochea, 2010), and A. tapajonica Carvalho et al., 2021. Adenomera diptyx is distinguished from A. amicorum, A. aurantiaca Carvalho et al., 2021, A. cotuba Carvalho & Giaretta, 2013, A. glauciae, A. gridipappi, A. inopinata, A. kayapo Carvalho et al., 2021, A. lutzi, A. phonotriccus Carvalho, Giaretta, Angulo, Haddad & Peloso, 2019, and A. tapajonica by the absence of an antebrachial tubercle.
Adenomera diptyx is distinguished from most congeners in advertisement call traits. The single-note call of A. diptyx differs from the multi-note calls of A. amicorum, A. aurantiaca, A. cotuba, A. glauciae, A. gridipappi, A. inopinata, and A. simonstuarti. Among Adenomera with single-note calls, call notes of A. diptyx are formed by incomplete pulses, whereas those of A. guarayo and A. phonotriccus are formed by complete pulses, and those of A. ajurauna, A. bokermanni, A. engelsi, A. kweti, A. lutzi, A. marmorata, A. nana, and A. saci are nonpulsed. From congeners also having single-note calls formed by incomplete pulses, A. diptyx differs by a higher note repetition rate (176–299 per minute; Table 3) from A. andreae (24–68 per minute), A. araucaria Kwet & Angulo, 2002 (23–46 per minute), A. chicomendesi (5–29 per minute), A. coca (66–84 per minute), A. heyeri (22–27 per minute), A. juikitam (32–52 per minute; retrieved from the raw dataset analyzed and published in Carvalho et al. 2021), A. kayapo (23–33 per minute), A. tapajonica (52–59 per minute), and A. thomei (10–23 per minute). Adenomera diptyx differs by a lower pulse number per note (2–6; Table 3) from A. martinezi (15–21). Adenomera diptyx cannot be completely distinguished acoustically from the allopatric A. hylaedactyla (characterized by Carvalho et al. 2019a). Despite the marginal overlap in value ranges of all analyzed traits, three temporal traits can be of help in their discrimination: note duration (A. diptyx: 28–49 ms, X = 38, SD = 5, N = 12 males; A. hylaedactyla: 41–89 ms, X = 59, SD = 9, N = 24 males), note repetition rate (A. diptyx: 176–299 per minute, X = 227, SD = 36, N = 12 males; A. hylaedactyla: 107–242 per minute, X = 154, SD = 32, N = 24 males), and pulse number (A. diptyx: 2–6 per note, X = 4, SD = 1, N = 12 males; A. hylaedactyla: 4–10 per note, X = 7 SD = 1, N = 24 males).
Advertisement call (Fig. 7, Table 3)
We characterized the advertisement call of A. diptyx based on 12 males from Paraguay and Brazil (N = 187 quantified calls and 645 quantified pulses; see Appendix 2 for locality data and voucher specimens). The call consists of single notes given at a repetition rate of 176 to 299 per minute (227± 36). Note duration varies from 28 to 49 (38 ± 5) ms, and the rise time is 8 to 74 % (30± 9) of note duration. Notes are formed by 2 to 6 (4± 1) incomplete pulses (i.e., not separated by silent gaps) emitted at a repetition rate of 65 to 239 per second (142 ± 22). The dominant frequency coincides with the second harmonic, ranging from 3984 to 5060 (4504±237) Hz. Notes can have a modest or pronounced frequency modulation, ranging from -47 to 689 (301 ±124) Hz.
Chromosome number
One specimen (UNNEC 13936, also genotyped) from Parque Nacional Cerro Corá (Amambay department, Paraguay) showed a diploid number 2n = 26 chromosomes and FN = 34. The karyotype is composed of three submetacentric pairs (pairs 1–3), one metacentric (pair 5), and nine telocentric (pairs 4 and 6–13) (Fig. 8A); pair 7 shows a conspicuous proximal secondary constriction NORs. The diploid number was confirmed in meiotic preparations from testes, in which 13 bivalents were observed (Fig. 8B).
Geographic distribution and habitat (Fig. 1)
Adenomera diptyx is known to occur in a few localities in Paraguay and Brazil. The distribution in Argentina and Bolivia is still uncertain and needs future sampling efforts in the field for the collection of specimens and acoustic data. In Paraguay, the occurrence records are the Parque Nacional Cerro Corá (Amambay Department) and the surroundings of Piribebuy (Cordillera Department). In Brazil, our record in Três Lagoas (eastern Mato Grosso do Sul, in border of São Paulo State) represents the easternmost range of the distribution of A. diptyx. The specimen was collected in a flooded area covered by tall grasses, right next to a river. The area seems to be seasonally flooded by the dynamics of the river. The population from Parque Nacional Cerro Corá (Amambay) was found on the bottom of dry ditches on the margin of road “Ruta N° 5” in a dense and tall (ca 1 m) grassland of Pennisetum purpureum Schumach. (elephant grass). Specimens were vocalizing on the ground, hidden in dead organic material. At Piribebuy, individuals were found in a partially urbanized area next to the Piribebuy River.
Additionally, DNA sequences from Lago Ypacaraí (Cordillera Department, Paraguay) and UHE Guaporé (Mato Grosso State, Brazil) provided by Fouquet et al. (2014) were also recovered as Adenomera diptyx. The presence of a long vertebral pinstripe in specimens from the Reserva de Recursos Manejados de Ybyturuzú (Guairá Department, Paraguay; Airaldi et al. 2013) and other specimens examined by us (see Appendix 1) from Laguna Blanca (San Pedro Department, Paraguay) confirm also its occurrence in these localities. The distribution of A. diptyx is mostly associated with the Alto Paraná Atlantic Forest and the Humid Chaco ecoregions, and also in the Chiquitano Dry Forest Ecoregion (Dinerstein et al. 2017).
Conservation
Adenomera diptyx seems to be a species that can adapt quite well to partially disturbed areas. The Amambay population is protected within the area of Parque Nacional Cerro Corá. However, outside of the park, vast extensions of forests have disappeared, and they were mostly replaced with pasture. The species is part of the open-habitat clade of Adenomera. These species are well adapted to open areas, both natural grasslands and savannas, and disturbed areas.
Adenomera diptyx (Boettger, 1885)
BRAZIL – Mato Grosso do Sul • 1 ♂; Três Lagoas; 20°51 ′ 42 ″ S, 51°44 ′ 38 ″ W; 294 m a.s.l.; CFBH 45426. – Mato Grosso • 4 specs (not sexed); Vale de São Domingos, U.H.E. Guaporé; 15°19 ′ 59 ″ S; 58°50 ′ 60 ″ W; MCP 6994, 7015, 7024, 7032 • 1 ♂; same collection data as for preceding; MCP 6996.
PARAGUAY – San Pedro • 5 specs (not sexed); Laguna Blanca; 23°48 ′ 26 ″ S, 56°16 ′ 46 ″ W; MNHNP 11637, 11663, 116664, 11670, 11679.
Adenomera diptyx (Boettger, 1885)
BRAZIL – Mato Grosso do Sul • Três Lagoas; 20°51 ′ 42 ′′ S, 51°44 ′ 38 ′′ W Adenomera _diptyxTresLagoasMS1cTRC_AAGm671: 18:53 h, 20 Dec 2020, air 27.1°C (CFBH 45426)
• Bela Vista; 22°04’27”S, 56°30’59”W Adenomera _diptyxBelaVistaMS1cTRC_AAGmt: 19:31 h, 17 Dec 2010, air 31.0°C
Adenomera _diptyxBelaVistaMS2bTRC_AAGmt: 19:16 h, 18 Dec 2010, air 32.0°C
PARAGUAY – Amambay • Parque Nacional Cerro Corá; 22°39 ′ 56 ′′ S, 56°00 ′ 24 ′′ W FZ-UNNE 0039: 12 Oct 2009, 16:20 h, air 19.1°C
FZ-UNNE 0042: 14 Oct 2009, 16:24 h, 31.4°C
FZ-UNNE 0332: 13 Jan 2015, 20:07 h, temperature unknown, upper 25°C
FZ-UNNE 0344: 15 Jan 2015, 18:32 h, temperature unknown, upper 25°C
– Cordillera • Piribebuy; 25°28 ′ 06 ′′ S, 57°02 ′ 33 ′′ W FZ-UNNE 0073: 13 Nov 2010, 19:10 h, air 23.6°C (CZCEN 0640)
FZ-UNNE 0074: 13 Nov 2010, 19:20 h, air 23.6°C (CZCEN 0641)
FZ-UNNE 0075: 13 Nov 2010, 19:35 h, air 22.3°C
FZ-UNNE 0079: 13 Nov 2010, 20:45 h, air 23°C
FZ-UNNE 0080: 13 Nov 2010, 20:55 h, air 23°C (CZCEN 0643)
description: Published as part of Zaracho, Víctor H., Lavilla, Esteban O., Carvalho, Thiago R., Motte, Martha & Basso, Néstor G., 2023, Redescription of Adenomera diptyx (Boettger, 1885) (Anura, Leptodactylidae) and description of a closely related new species, pp. 1-45 in European Journal of Taxonomy 888 (1) on pages 9-42, DOI: 10.5852/ejt.2023.888.2205, http://zenodo.org/record/8222476