Short Communication |
Corresponding author: Alberto Sánchez-Vialas ( alberto.alytes@gmail.com ) Academic editor: Annemarie Ohler
© 2017 Alberto Sánchez-Vialas, Marta Calvo-Revuelta, Rafael Márquez.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sánchez-Vialas A, Calvo-Revuelta M, Márquez R (2017) Ptychadena in Mauritania and the first record of Ptychadena schillukorum. ZooKeys 673: 125-133. https://doi.org/10.3897/zookeys.673.10265
|
The study of specimens of the genus Ptychadena of the herpetological collection of the Museo Nacional de Ciencias Naturales de Madrid reveals the first record of Ptychadena schillukorum from Mauritania, extending the known distribution range of the species in West Africa more than 450 km northwards. A key is provided for the four Mauritanian species of Ptychadena to solve problems in identification encountered in previous studies.
Herpetological collection, identification key, Ptychadena schillukorum , Sahel, taxonomic problems, West Africa
Ptychadena Boulenger, 1917 is a genus of medium-sized Afrotropical frogs that comprises 50 known living species (
The western portions of the Sahel ecoregion includes a diversified group of species of Ptychadena, namely P. pumilio (Boulenger, 1920), P. bibroni (Hallowell, 1845), P. tellini (Peracca, 1904) (as P. schubotzi (Sternfeld, 1917)), P. longirostris (Peters, 1870), P. oxyrhynchus (Smith, 1849), P. trinodis (Boettger, 1881), P. mascareniensis (Dúmeril & Bibron, 1841), P. tournieri (Guibé & Lamotte, 1955), P. stenocephala (Boulenger, 1901), P. submascareniensis (Guibé & Lamotte, 1953), P. retropunctata (Angel, 1949), and P. schillukorum (Werner, 1908) (as P. floweri, (Boulenger 1917)) (
Ptychadena trinodis differs from the other two species of Ptychadena recorded in Mauritania by the presence of a tarsal tubercle and by very large inner and outer metatarsal tubercles; in Mauritania it has been reported in two localities: Guelta Oumm Lebare and Guelta Metraucha. Ptychadena cf. mascareniensis is cited only at one locality in Mauritania: Zoueina; it differs from P. bibroni by a very subtle outer metatarsal tubercle, lack of supernumerary tubercles on toe IV, dorsal median ridges that reach the posterior edge of the eyes, different webbing formula (22/3–3 in P. cf. mascareniensis and 2–21/3 in P. bibroni), and by a continuous lateral ridge which is broken in P. bibroni. Ptychadena bibroni is known by two records in Mauritania: Kaedi and Mahmoûdé Lake (
Abrupt climate changes and hydrological fluctuations that took place in southern Mauritania during Pleistocene–Holocene, created a dynamic transitional zone promoting dispersal and contraction of distributional areas of Afrotropical species (
In this note, a new species record of Ptychadena is reported from southern Mauritania based on material of the herpetological collection of the Museo Nacional de Ciencias Naturales of Madrid (
The specimens of Ptychadena held at the National Museum of Natural Sciences of Madrid (
Geographic records published of the species of Ptychadena from Mauritania identified at species level. Yellow dot from Senegal represent the previous northernmost record in West Africa of P. schillukorum. Green dot represent the localities were P. bibroni has been recorded in Mauritania. Localities with presence of P. trinodis are represented by red dots. The record of P. cf. mascareniensis is the blue coloured dot. The new record of P. schillukorum from Mauritania is shown as a yellow triangle (map created from http://www.simplemappr.net/).
Morphological characters of
P. bibroni | P. cf. mascareniensis | P. trinodis | P. schillukorum | |
---|---|---|---|---|
Catalog number ( |
44071–44074 | 41784 | 41783 | 43846–43855; 42221–42231; 42208; 42210–42216 |
Tarsal tubercle | absent | absent | present | absent |
Inner metatarsal tubercle as long as toe I | absent | absent | present | absent |
Outer metatarsal tubercle distinctive | present | absent | present | absent |
Lateral ridge continuous | absent | ? | present | absent |
Dorsal ridges continuous | present | ? | present | absent |
Mottled pattern of thigh | absent | present | absent | present |
Number of phalanges of toe 4 free of web | 2 | 3 | 2 | 3 |
Supernumerary tubercles on toe IV | present | absent | absent | absent |
Morphological characters used in this study for comparison between the species of Ptychadena from Mauritania are: tarsal tubercle, inner metatarsal tubercle, outer metatarsal tubercle, lateral ridge, dorsal ridge, thigh pattern, supernumerary tubercles on toes and webbing extension in the fourth toe (Table
The measure of the range extension of P. schillukorum was taken by airline distance using Google Earth tool, from the northern most locality in West Africa at Niokolo-Koba in Senegal to Aleg in Mauritania.
The poor conditions in which we found the specimen of P. cf. mascareniensis collected in Mauritania by Padial and De la Riva (
The morphology of the studied individuals of Ptychadena schillukorum from Mauritania fitted with the description of the species (
The examined individuals
The nearest locality to Mauritania where Ptychadena schillukorum has been reported is in southern Senegal at Niokolo-Koba (
Ptychadena schillukorum (Fig.
Aleg is located in the Sahel region, characterised by a subtropical dry arid climate with rainy season from July to October. Most individuals were collected in October 1998 by RM, a few days after a (sporadic) event of rainfall that caused the formation of shallow pools and the growth of herbaceous vegetation on the normally barren sand (Fig.
The four Mauritanian species of Ptychadena (Figure
Based on
The four species of Ptychadena recorded in Mauritania: Ptychadena bibroni from Gourel Yoba, Senegal; male specimen, not collected (A), Ptychadena trinodis from Toubakouta, Senegal; male specimen, not collected (B), Ptychadena cf. mascareniensis from Zoueina, Mauritania (
1 | Tarsal tubercle present. Metatarsal tubercles large. Inner metatarsal tubercle almost as long as the toe 1 | P. trinodis |
– | Lack of tarsal tubercle. Inner metatarsal tubercle smaller than 0.6 of the length of toe 1 | 2 |
2 | Dorsal ridges continuous | 3 |
– | Dorsal ridges discontinuous, broken into warts. | P. schillukorum |
3 | Dorsal median ridges to mid-dorsum. Lateral ridge discontinuous. Supernumerary tubercles on toe IV present | P. bibroni |
– | Dorsal median ridges to posterior edge of the eyes. Lateral ridge continuous. Supernumerary tubercles on toe IV absent | P. mascareniensis |
Studies concerning amphibian fauna in Mauritania are scarce, suggesting that other populations of Ptychadena schillukorum may be discovered in the future. Molecular studies of P. schillukorum should be carried out to know how complex is the species across their distribution (expected to be high or a group of species as suggested by
We are grateful to Mario García París and Iñigo Martínez-Solano for advice and comments on the manuscript. Collection in Mauritania was possible thanks to Santiago Martínez de Orense who provided lodging, transportation, and help in the field.
This research was partially funded by project TATANKA (CGL2011-25062) obtained from Ministerio de Ciencia e Innovación, Spain. We are grateful to José Manuel Padial who kindly provided the picture 5C, and to Daniel Hinkley who revised the MS in English. We are also deeply grateful to Annemarie Ohler, Edgar Lehr and to an anonymous reviewer whose comments have helped in improving the manuscript.