Bio-sketches and partitioning of sympatric reed frogs, genus Hyperolius (Amphibia; Hyperoliidae), in two humid tropical African forest regions
Author
Lötters, S.
Author
Schick, S.
Author
Scheelke, K.
Author
Teege, P.
Author
Kosuch, J.
Author
Rotich, D.
Author
Veith, M.
text
Journal of Natural History
2004
2004-08-31
38
15
1969
1997
http://dx.doi.org/10.1080/00222930310001613584
journal article
10.1080/00222930310001613584
1464-5262
4676048
Hyperolius lateralis
Laurent
(figure 9)
This reed frog is known to range from north-western
Tanzania
to the eastern
Democratic Republic of Congo
and to western
Kenya
; it occurs in bush land and forest (
Schiøtz, 1975
,
1999
). Several subspecies from
Rwanda
,
Burundi
and western
Uganda
were named by Laurent (e.g. 1951). According to
Schiøtz (1975
,
1999
), they seem to reflect variation among populations of a single taxon only. We examined the female
holotypes
of the forms
capnodogaster
,
pulcherrimus
and
subolivaceus
and have the impression that they could represent distinct taxa. Comprehensive investigation remains to be carried out including also the similar
H. castaneus
Ahl
and its junior synonyms (from eastern
Democratic Republic of Congo
,
Rwanda
and western
Uganda
). Kenyan material is referable to the nominotypical form and well coincides with the female
holotype
(
SVL
25.0 mm).
Diagnosis.
SVL
males 23.6¡
0.62 mm
(
22.5–24.2 mm
,
n
~7); according to
Schiøtz (1975: 129)
,
SVL
of one female 25.0 mm (a non-collected female had
SVL
24.3 mm
); (2)
TIBL
/
SVL
0.47¡0.01 (0.46–0.49,
n
~7), HW/
SVL
0.32¡0.02 (0.3–0.35,
n
~7); (3) dorsal surface finely coarse, tuberculate below eye and tympanic area; (4) snout shape dorsally and laterally rounded, nares visible from above; (5) E-N/EYE 0.68¡0.08 (0.58–0.76,
n
~7), canthus rostralis straight from tip of snout to nostril and concave from nostril to eye; (6) tympanum distinct or covered by thick skin,
TYMP
/EYE 0.31–0.36 (
n
~2); (7)
FOOT
/
TIBL
0.86¡0.03 (0.85–0.92,
n
~7); (8) foot webbing formula: 1(K–1), 2i(1) 2e(K), 3i(1) 3e(K), 4i(1) 4e(1), 5(K); (9) PhJ and PhF are dorsally olive, brownish or yellowish green, with or without diffuse dark brown and/or bright yellow spotting, sometimes with a faint, thin light dorsolateral stripe, and in PhF a cream and/or bright yellow irregular lateral line or lateral marbling from below or behind eye to groin which always is bordered by dark brown; a dark brown canthal line may be present, ventral sides are translucent pink to reddish including sole and palm, webbing as well as parts of the upper sides of toes and fingers; the gular flap of males is dark yellowish golden; the iris is light brownish grey (information provided is based on collected and numerous non-collected specimens of both sexes); (10) for sequence of 560 bp fragment of mitochondrial DNA of the 16S ribosomal gene see GenBank under
AY323924
(~
NMK
A/3925/1); (11)
LTRF
1/3.
FIG. 9. Male
Hyperolius lateralis
(PhF), Kenya: Kakamega Forest (specimen not collected).
Hyperolius lateralis
is similar to
H. cinnamomeoventris
and
H. castaneus
, which are both sympatric in part. According to
Schiøtz (1975
,
1999
), the latter is very variable and can be indistinguishable from
H. lateralis
PhJ (
H. castaneus
does not fall into PhJ and PhF). It seems that a dark canthal line is always present in
H. castaneus
(versus occasionally present in
H. lateralis
). For differentiation from
H.
cf.
cinnamomeoventris
see below.
Life history.
As
elsewhere, in the
Kakamega
Forest
,
H. lateralis
is a nocturnal arboreal species.
We
observed it
between April and June
only.
Males
and females were found in disturbed primary forest, and at its edge in swampy areas or at ponds where males called from vegetation v
1.5 m
above ground. This reed frog tends to be intermediate between explosive and prolonged breeding strategies. Two clutches were fixed to vegetation above the water surface, containing 94 and
179 eggs
(half black, half cream) each
ca
1.6–1.9 mm
in diameter (without jelly). Larvae are lentic and omnivorous
.
The advertisement of this species can be described as a ‘squashed peep’. It consists of a single note. Graphic and numerical characteristics (figure 2G; table 1) are comparable to data provided by
Schiøtz (1975)
. However, frequency range and dominant frequency are somewhat higher, with overlap.