Research Article |
Corresponding author: Arthur Tiutenko ( arthur.tiutenko@fau.de ) Academic editor: Günter Gollmann
© 2019 Arthur Tiutenko, Oleksandr Zinenko.
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:
Tiutenko A, Zinenko O (2019) Tadpole of Leptopelis ragazzii (Boulenger, 1896), Shoa Forest Tree Frog (Anura, Arthroleptidae). Herpetozoa 32: 51-55. https://doi.org/10.3897/herpetozoa.32.e35742
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The tadpole of poorly studied Leptopelis ragazzii (Boulenger, 1896), a high-altitude tree frog species from the Ethiopian highlands, is described for the first time and compared with closely related sympatric species – L. gramineus (Boulenger, 1898) and L. vannutellii (Boulenger, 1898).
Die Larve des bis jetzt wenig erforschten Leptopelis ragazzii (Boulenger, 1896), einer Baumfroschart aus den Höhenlagen des Äthiopischen Hochlandes, wird zum ersten Mal beschrieben und mit den nah verwanden sympatrischen Arten L. gramineus (Boulenger, 1898) und L. vannutellii (Boulenger, 1898) verglichen.
Arthroleptidae, Ethiopia, Harenna Forest, larva, Leptopelis gramineus, Leptopelis vannutellii, tadpole
Leptopelis ragazzii (Boulenger, 1896) is a high-altitude species of tree frog that has a wide but patchy distribution in the southern Ethiopian highlands. It is often reported from both sides of the Great Rift Valley where it seems not to occur at elevations below 2,200 m a.s.l. (though one specimen was obtained at 1,930 m –
Apart from the usually acknowledged taxonomic and phylogenetic relevance, in the case of L. ragazzii furthering our knowledge of tadpoles and breeding biology in general is certainly helpful for recognition of habitats critically important to the long-term survival of this species which is considered to be vulnerable (
Leptopelis ragazzii tadpoles were often reported in the course of various surveys and research activities in a number of localities, but to date no detailed description of the tadpole has been published. During our fieldwork in the Harenna Forest, southern Ethiopia, we found, besides adult L. ragazzii, tadpoles in advanced development stages and could study their morphology.
The description is based on 3 specimens in development Stage 25, 1 in Stage 24, and 1 in Stage 28 (Gosner, 1960) found on November 4th, 5th and 6th, 2018, in the north-eastern Harenna Forest (Bale Zone, Ethiopia), at 06.92935N, 40.13629E, 2,610 m a.s.l., in a shallow river flowing fast through dense forest of tall trees. The voucher specimens are housed in the Zoological State Collection Munich, Germany (ZSM 285/2018 and 286/2018) and in the Museum of Nature at V. N. Karazin National University, Kharkiv, Ukraine (MNKNU Г-2000 – 2 specimens, and Г-2001). The specimens were euthanised by brief immersion in 0.1% solution of sodium thiopental and, after fixation in 10% formalin, transferred to 70% ethanol for final preservation.
We identified the genus by morphological characters according to the key to genera of African (sub-Saharan) Anura from
Since in this area the range of grassland dwelling and fossorial L. gramineus overlaps with the range of L. ragazzii that is, however, arboreal and occupies forest habitats, we compared our vouchers also with the following tadpoles of L. gramineus in museum collections: ZSM 17/2017 and 18/2017, MNKNU Г-2002 and Г-2003.
For terminology in describing tadpoles we follow terms and descriptive characters by McDiarmid and Altig 1999;
The illustrations (Figs
The tadpole occupies lotic habitats and is eel-like, free swimming and benthic.
See Table
Morphometrics of tadpoles (in millimetres); for abbreviations see “Material and methods”.
Accession # | G | SVL | TL | BW | BH | AH | AW | VF | DF | SED | IOD | ED | SSD | SL | ODW | KF |
MNKNU Г-2000(1) | 24 | 7.5 | 14.5 | 4.6 | 3.4 | 1.3 | 1.3 | 0.9 | 0.8 | 1.4 | 2.7 | 0.6 | 3.2 | 0.8 | 0.8 | 1 |
2+2 | ||||||||||||||||
2 | ||||||||||||||||
MNKNU Г-2000(2) | 25 | 9.5 | 30.8 | 4.8 | 3.7 | 2.9 | 1.8 | 2.0 | 1.8 | 2.6 | 3.3 | 1.0 | 4.3 | 1.0 | 2.3 | 1 |
2+2 | ||||||||||||||||
1+1 | ||||||||||||||||
1 | ||||||||||||||||
MNKNU Г-2001 | 25 | 9.8 | 35.5 | 4.9 | 3.8 | 2.2 | 1.6 | 1.8 | 1.7 | 2.0 | 2.8 | 0.8 | 3.9 | 1.0 | 2.6 | 1 |
2+2 | ||||||||||||||||
2 | ||||||||||||||||
ZSM 285/2018 | 28 | 12.4 | 26.8 | 6.8 | 5.3 | 3.2 | 1.9 | 1.4 | 1.4 | 2.8 | 3.0 | 1.0 | 5.4 | 1.2 | 2.5 | 1 |
2+2 | ||||||||||||||||
1+1 | ||||||||||||||||
2 | ||||||||||||||||
ZSM 286/2018 | 25 | 10.6 | 24.1 | 6.4 | 5.1 | 2.3 | 1.5 | 1.4 | 1.2 | 2.3 | 3.2 | 1.0 | 4.3 | 1.1 | 2.4 | 1 |
2+2 | ||||||||||||||||
3 |
The tail length is 0.78 in total. Tail tip is narrow, but blunt. Muscle axis strong and pronounced. Dorsal fin originates posteriorly to the dorsal tail-body junction with maximum height at approximately 2/3 of the tail length and is slightly curved; ventral fin originates on the ventral terminus of the body and is lower than the tail muscle with maximum height of approximately 1/2 of the tail length; maximum height in ventral fin a little greater (DF/VF = 0.94); maximum tail height including fins approximately equals body height; tail axis width (in dorsal view) 0.38 of body width (AW/BW); maximum height of tail axis (at base) 0.57 of body height (AH/BH); tail axis height (at base) higher than maximum height of dorsal fin (DF/AH = 0.62). Vent tube dextral, basicaudal.
The oral disc (Fig.
There are two or three continuous posterior keratodont rows. The number of anterior rows seems to remain constant: one continuous and two interrupted. The following keratodont formulas occur: 1:2+2 / 2; 1:2+2 / 1+1:1; 1:2+2 / 1+1:2; 1:2+2 / 3.
Jaw sheaths are moderately strong; posterior strongly V-shaped and overall heavier than anterior; the latter is wavy.
The tadpole is generally grey or grey-brown in appearance, both in preservative and in life. Dorsum is darker than venter that is also grey coloured. Larger and older specimens in the series have more dark speckles on dorsal fin, hence the overall appearance of the animal becomes darker and more speckled in advanced development stages. Median line of the tail muscle is dark pigmented. The venter skin is opaque, intestines are not visible under normal light, or (in smaller specimens) may be noticed only as shaded contours. The iris is grey.
The easiest, and quite reliable method of distinguishing the larvae of Ethiopian Leptopelis is through assessment of their geographical or ecological separation, as no species seem to occur syntopically even if their ranges overlap. Attempts at identification by external morphology only may fail or lead to a wrong conclusion.
Like the adult frogs, the tadpoles of L. ragazzii and L. vannutellii are very similar in size and shape (for an illustration of L. vannutellii tadpole see
The tadpole of L. ragazzii also resembles the tadpole of L. gramineus, from which it slightly differs by general body and tail shape (see illustration of L. gramineus in
Just like in L. vannutellii and L. gramineus (
In the tadpoles of this genus, the nares seem to appear at later stages, from Stage 34 on (compare
The fieldwork was conducted with the permission and support of the Bale Zone administration and the administrations of the district Goba. We thank all representatives of these institutions who facilitated our work and the inhabitants of the village of Wajitu Shabe who helped us in the field.
This study is part of a project funded by the National Geographic Society, grant WW-243S-17. We thank the donors and the NGS Committee for Research and Exploration for this support.
We are grateful to Wolfgang Böhme, Ursula Bott and Morris Flecks who kindly gave us access to specimens housed in
Our thanks are also due to Kristaps Sokolovskis (Lund University, Sweden) who was a member of our team in the field and found a live specimen of adult L. ragazzii.