AMPHIBIAWEB
Arthroleptella draconella
family: Pyxicephalidae
subfamily: Cacosterninae
 
Species Description: Turner A, Channing A. 2017. Three new species of Arthroleptella Hewitt, 1926 (Anura: Pyxicephalidae) from the Cape Fold Mountains, South Africa. African Journal of Herpetology 66: 53–78.
Conservation Status (definitions)
IUCN (Red List) Status
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

 

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Description
Arthroleptella draconella is a small, squat frog described from six males and one female. The snout to vent length ranges from 10.75 to 14.45 millimeters. The frog’s short snout is blunt and rounded with a length that is slightly shorter than the width of its eye. From the ventrum, the eye and lip are visible. The eye has a horizontal pupil with a visibly bumpy eyelid. No tympanum is visible. A series of rictal glands connect the anterior end of the jaw to the insertion of the upper arm. The dorsum is textured with slight bumps. The lateral skin is smooth with no folds. The palms are smooth and the digits are short. The fingers and toes are unwebbed with tips that are slightly swollen or expanded respectively. The relative finger lengths are III > II > IV > I and the relative toe lengths are IV > III > V > II > I. The inner metatarsal tubercles are rounded and smooth, but the outer metatarsal tubercles are poorly developed (Turner and Channing 2017).

Arthroleptella draconella is primarily differentiated from other members of its genus through advertisement calls and genetic analysis; however, there are a few differentiating morphological traits. Arthroleptella rugosa has well-developed and prominent bumps on the dorsum in both sexes whereas the bumps on the dorsum of A. draconella are less pronounced in males and absent the in one known female specimen. In addition, the advertisement call of A. draconella has unique chirps and chuckles that are not present in the calls of A. rugosa. The calls of A. lightfooti and A. villiersi have a lower average dominant frequency. The call of A. subvoice is longer in length and has lower note and pulse rates. Arthroleptella atermina has longer hind limbs and shorter calls with fewer notes and pulses. Arthroleptella landdrosia, A. drewesii, and A. kogelbergensis all have longer hind limbs and longer advertisement calls with fewer pulses per call (Turner and Channing 2017).

In life, Arthroleptella draconella tends to have a mottled orange-brown to red-brown coloration or grey-brown with no regular patterning. There is a distinct dark patch behind the eye that forms a short eye stripe. The iris of the eye is golden. The ventral side has a grey mottling that is dark toward the anterior side and lighter toward the posterior side (Turner and Channing 2017).

There is variation in male coloration and potential sexual dimorphism in coloration and skin texture may. Dorsal coloration in males can include dark brown mottling with a red-brown background. The coloration on the upper arms can be orange. Males can also have a dark patch anterior to the eye, but never a full mask. The mottled coloration on the chest and throat can be a darker grey-black. The color of the iris in males can be copper-colored. The single female specimen from the species description had a smooth dorsum with a near uniform dark grey-brown coloration and very fine dark mottling that extended to the upper legs. She also had a full dark facemask and copper-brown iris (Turner and Channing 2017).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: South Africa

 

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Arthroleptella draconella is primarily known to occur on the Klein Drakenstein, Hawequas, and Du Toits Kloof Mountains of South Africa at altitudes ranging from 500 m to 1000 m. These frogs are generally found near mountain seeps of the sandstone fynbos because the dense vegetation and mountain seeps allow for yearlong retention of surface moisture. However, suitable habitats are few and far in between (Turner and Channing 2017).

Life History, Abundance, Activity, and Special Behaviors
Due to their preferred habitat of dense vegetation, these frogs are very elusive and, as such, not much is known about their life history (Turner and Channing 2017).

Males perform an advertisement call that contains 2 to 16 click-like notes, 6 per call on average. The average frequency of the call is 4334 ± 231 Hz. These calls have an average duration of 0.732 ± 0.340 seconds, a note rate of 8.84 ± 2.32 notes per second, a pulse rate of 20.72 ± 8.34 pulses per second, and a pulse count of 13.82 ± 5.56 pulses. The calling behavior and performance is affected by temperature (Turner and Channing 2017).

Trends and Threats
Since these frogs reside in mountainous regions, there is minimal threat by human development. However, the species only has an estimated extent of occurrence of 299.0 km2 and a known area of occupancy of 32.4 km2, which, along with a decline in habitat extent and quality, invokes the IUCN Red List “Endangered” criteria of B1b(iii) and B2b(iii) (Turner and Channing 2017). More research is needed to determine if other criteria are met.

The primary threat to Arthroleptella draconella is habitat loss through invasive plant species, primarily Pinus pinaster and Hakea sericea. These invasive plant species disrupt the mountain seeps and the moisture retention that is fostered by the native plants and required by these frogs. In addition, the invasive pines increase the fire hazard of the area as a result of the dry fuel provided by the woody plant material. Other populations of Arthroleptella frogs have shown significant population fluctuations as a result of wild fire (Turner and Channing 2017).

Possible reasons for amphibian decline

General habitat alteration and loss
Subtle changes to necessary specialized habitat

Comments
The species authority is: Turner, A., Channing, A. (2017). “Three new species of Arthroleptella Hewitt, 1926 (Anura: Pyxicephalidae) from the Cape Fold Mountains, South Africa.” African Journal of Herpetology, 66(1), 53-78.

Arthroleptella draconella is a member of the “click-clade” of South African frogs, which are found allopatrically in the Cape Fold Mountains (Turner and Channing 2017).

Bayesian Inference of sequences from 12S and 16S mitochondrial and the RAG-1 nuclear gene indicates that A. draconella is sister to the clade formed by A. atermina, A. drewesii, A. landdorsia, and A. kogelbergensis (Turner and Channing 2017).

Arthroleptella draconella was previously considered a population of A. bicolor. However, molecular analysis showed that populations once considered A. bicolor were actually composed of at least three species. The range of A. bicolor is now restricted to the mountains of Limietberg and Waterval (Turner and Channing 2017).

The specific epithet, draconella, is based on the Latin word for dragon in feminine diminutive form “draco”. This is in reference to one of the localities in which the frog can be found, the Klein Drakenstein Mountains (Turner and Channing 2017).

References

Turner, A., Channing, A. (2017). ''Three new species of Arthroleptella Hewitt, 1926 (Anura: Pyxicephalidae) from the Cape Fold Mountains, South Africa.'' African Journal of Herpetology, 66(1), 53-78.



Written by Jerry Jin (Jerry.j.jin AT berkeley.edu), UC Berkeley
First submitted 2018-07-09
Edited by Ann T. Chang (2018-07-09)

Species Account Citation: AmphibiaWeb 2018 Arthroleptella draconella <http://amphibiaweb.org/species/8642> University of California, Berkeley, CA, USA. Accessed Oct 16, 2018.



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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 Oct 2018.

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