Range and habitat
We detected L. nigriventer at the known and newly identified sites within the Hula Nature Reserve, and at another location, about 1 km southeast of the reserve borders near the small village Yesod HaMa’ala (Fig. 1 C–F). In total, we observed 64 adult females, 42 adult males, 29 juveniles (Fig. 2) and 40 tadpoles. Of these, six middle-sized to large individuals (SVL 33.8–76.8 mm) were discovered within the reserve, while 112 medium to large-sized individuals (SVL 43.0–128.4 mm), 19 small individuals (SVL 16.2–30.1 mm; Fig. 2 M) as well as tadpoles at Gosner stages 25–34 were recorded at Yesod HaMa’ala. Based on our specimen records we estimate L. nigriventer to occupy an area of at least 6.5 km², but the number of active reproductive sites is uncertain.
The species was found to exploit different kinds of terrestrial and aquatic habitats:
(1) In the Hula Nature Reserve all individuals were discovered in terrestrial habitats. As a former part of the Hula marshes and lake, the organic soil at this site is peaty, damp and loose, and covered by a ca. 20–30 cm layer of humid decomposed leaf litter. Most individuals (including 9 of the 14 individuals found prior to our surveys) were found beneath this layer within a dense thicket of blackberry (Rubus sanguineus Frivaldszky, 1835), reeds (Phragmites australis (Cavanilles) Trinius Ex Steudel, 1840) and occasionally fig trees (Ficus carica Linnaeus, 1753). The majority of the reserve’s water bodies are lentic and about 20–30% of the permanently flooded area is covered by dense stands of reeds and Papyrus sedge (Cyperus papyrus Linnaeus, 1753). It is, however, uncertain which of the water bodies of the Hula Nature Reserve are used by L. nigriventer as no individuals were found here in their aquatic habitat, and no eggs or larvae were detected.
(2) At the site near Yesod HaMa’ala, all individuals were found in the water or at the slopes of a ~600 m long ditch. This ditch has a permanent source of water from a small spring and dense vegetation both in and next to the water. The water is very slowly flowing and depth is substantial (up to ca. 150 cm) but starting at depths of ca. 10–100 cm. A deep layer of mud covers the bottom of the ditch and aquatic vegetation covers much of the water’s surface (comprising dense P. australis growths, water lettuce (Pistia stratiotes Linnaeus, 1753), and duckweed, Lemna minor Linnaeus, 1753). At the edges of the ditch, the mineral soil is compressed, sandy and in the dry season less damp than in the reserve. Individuals in terrestrial habitat were detected either beneath dried or half-dried grass tufts, or in natural cavities or small burrows at the water edge dug by semi-terrestrial freshwater crabs (Potamon potamios (Olivier, 1804)) or small mammals. The Latonia individuals encountered at this site displayed a strikingly high percentage of injury. Of the 112 medium to large-sized frogs (> 42 mm), 28% had old or recent minor injuries mainly on the hind limbs (Fig. 3), while such injuries were not detected in juvenile frogs or in individuals found in the Hula Nature Reserve. However, the ditch is less frequently visited by migrating birds or larger mammals and has fewer fish species than other, major water bodies in the Hula Nature Reserve (see S2 in the Supplement).