Morphology and Systematics of Kalophrynus interlineatus-pleurostigma Populations (Anura: Microhylidae: Kalophryninae) and a Taxonomy of the Genus Kalophrynus Tschudi, Asian Sticky Frogs
Author
Zug, George R.
text
Proceedings of the California Academy of Sciences
2015
2015-04-15
62
5
135
190
journal article
10.5281/zenodo.11512244
0068-547X
11512244
AD651C54-BC39-4A21-A0CA-3B9B8309A0BB
Kalophrynus interlineatus
(
Blyth, 1855
) Striped Sticky Frog
Figures 7
,
11C
.
Engystoma
(?)
interlineatum
Blyth, 1855
,
Journal of the
Asiatic Society of Bengal
[1854] 23:732 [
type
locality: “
Pegu
”,
Myanmar
; see Comments below]
.
TYPE
MATERIAL
.—
LECTOTYPE
:
Natural History Museum
United Kingdom
, formerly
British Museum of Natural History
68.4.3.128, recataloged as
1947.2.31.
26
.
PARALECTOTYPE
:
NHMUK
/
BMNH 68
.4.3. 129, recataloged as
1947.2.31.
27.
See
discussion on the assignment of type specimens in the
Comments
section below
.
DESCRIPTION
AND
INTRAPOPULATIONAL
VARIATION
.
Moderate-sized adults, not sexually dimorphic although females average larger (mean 41.5, 35.0–46.
4 mm
SVL
) than males (39.2, 33.7–44.
6 mm
). These differences are reflected in the other measurements: HeadL 11.2–15.
3 mm
♀♀
, 10.3–13.
4 mm
♂♂
; HeadW 12.7–15.
1 mm
♀♀
, 11.3–13.
5 mm
♂♂
; SnEye 4.3–5.
7 mm
♀♀
, 3.8–
5.3 mm
♂♂
; NarEye 2.8–
3.7 mm
♀♀
, 2.3–
3.8 mm
♂♂
; EyeD 3.6–
4.5 mm
♀♀
, 3.4–
4.5 mm
♂♂
; Tymp 3.1–3.
8 mm
♀♀
, 2.6–
3.5 mm
♂♂
; ForarmL 9.0–13.
2 mm
♀♀
, 8.7–12.
2 mm
♂♂
; HandL 8.4–11.
3 mm
♀♀
, 7.7–10.0 mm
♂♂
; ThghL 13.7–18.
6 mm
♀♀
, 14.1–17.
7 mm
♂♂
; CrusL 13.0–16.
2 mm
♀♀
, 12.0–15.
6 mm
♂♂
; TarsL 8.5–10.
4 mm
♀♀
, 7.9–10.
8 mm
♂♂
; HndfL 13.0–16.
6 mm
♀♀
, 11.7–15.
8 mm
♂♂
.
Body proportion means differ between females and males, although not greatly so (all values are percent): HeadL/
SVL
29–
36 ♀♀
, 28–
31 ♂♂
;
HeadW/
SVL
31–
36 ♀♀
, 29–
36 ♂♂
; HeadW/HeadL 95–
11 ♀♀
, 95–
116 ♂♂
; SnEye/HeadL 36–
41 ♀♀
, 36–
45 ♂♂
; NarEye/SnEye 56–
66 ♀♀
, 54–
78 ♂♂
; EyeD/HeadL 28–
36 ♀♀
, 30–
37 ♂♂
; Tymp/EyeD 72–
100 ♀♀
, 71–
79 ♂♂
;
Forarm/
SVL
25–
31 ♀♀
, 24–
31 ♂♂
; Forarm/CrusL 69–
83 ♀♀
, 65–
86 ♂♂
;
HndlL/
SVL
127–
147 ♀♀
, 122–
148 ♂♂
;
CrusL/
SVL
34–
40 ♀♀
, 30–
39 ♂♂
; CrusL/ThghL 83–
95 ♀♀
, 81–
96 ♂♂
; TarsL/ThghL 51–
62 ♀♀
, 53–
63 ♂♂
;
HndfL/
SVL
30–
40 ♀♀
, 30–
40 ♂♂
; HndfL/ThghL 84–
95 ♀♀
, 80–
93 ♂♂
.
I noted earlier in the Morphometric section that the
Tanintharyi
sample displayed no significant sexual dimorphism and that females were significantly larger in the SE Asia sample. When the samples are combined, the overall size dimorphism declines, although a few traits remain dimorphic. Females have larger heads than males; HeadL, HeadW, and SnEye average larger, but none of the other head metrics do, and there are no proportional differences in the head or body metrics. There is strong dimorphism in ForarmL and HndfL with females being larger in both.
In their amphibian atlas,
Fei et al. (2010)
reported Chinese males as
32–38 mm
SVL
and females to
40 mm
. These adult lengths are smaller, likely significantly so, than my sample which is comprised of frogs from more southern locations.
Karsen et al. (1986)
did not give a range or mean for
Hong Kong
K. interlineatus
and his “up to
6 cm
long”, contrasts sharply with Fei’s lengths and is much larger than the maximum
SVL
in our sample or that reported for this species elsewhere.
Bourret (1942)
gave single value adult sizes of
38 mm
SVL
for males and
44 mm
for females.
Berry (1975)
gave total lengths of Peninsular
Malaysia
K. interlineatus
as
47–58 mm
. I interpret his total length as
SVL
, hence his size data are greater than the range for my Tanintharyi and Thai-Indochina samples and more closely match the size of
K. meizon
. Although I do not reject his data, I am uncertain how to interpret it and have not included his values in
Table 3
. Manthey and Grossmann (1997), in contrast, gave
35–41 mm
SVL
for males and
38–46 mm
for females from Peninsular
Malaysia
, matching my adult size range for the Tanintharyi and Thai-Indochina samples. A more recent study of Malaysian
K. interlineatus
(
Chan et al, 2011
) reported 33.7–38.
1 mm
SVL
for adult males (
n =
7) and 41.1–47.
3 mm
SVL
for adult females (
n
=10); these values also match my values for the more northern Thai-Indochinese sample.
Tongue is broadly obovate, posterior edge smooth; vomerine teeth are absent; palatal fold morphology appears relatively uniform among individuals although these data are not quantified. Vomerine folds are smoothedged flaps, one adjacent to each choanae and widely separated from its opposite. Postorbital folds are more variable; in Tanintharyi frogs, a pair of folds is separated on the midline, and each side has two or three. Variation in the Thai and Indochina frogs is described in the morphology section. Buccal fold is a continuous lobular fold with abutting lobes and each lobe a low, round-edged rectangle. See Fei et al. (2005) for an illustration of the buccal cavity of a Chinese
K. interlineatus
.
Fingers lack webbing. Both finger and toe tips are bluntly rounded. Subarticular tubercle are well developed on the digits; only third finger bears a subarticular tubercle on free portion of digit; all fingers have a tubercle at their base and another row between a large, circular, nearly medial outer palmar tubercle. For the hindfoot, each toe has a basal subarticular tubercle, third and fifth toes have an addition tubercle on free portion of digit, two tubercles on fourth toe. Inner and outer metatarsal tubercles are present; inner is large, nearly circular to elliptical; outer small to nearly absent and circular. Toes modestly webbed WebIII2 median 2.0 (1.0–3.0), WebIV1 1.0 (0.5–2.0). Digit lengths nearly constant for fore- and hindfeet; finger formula 3>2≈1>4; toe formula 4>3>5>2>1.
FIGURE
7. Images of lectotype of
Kalophrynus interlineatus
(NHMUK/BMNH 1947. 2.31.26, female) in (A) dorsal and (B) ventral views, and of paralectotype (NHMUK/BMNH 1947. 2.31.27, male) in (C) dorsal view [photographer G.R. Zug].
Color pattern variation statistics for entire sample of juvenile and adults are (median and range): HeadMid 1, 0–2; HeadPsag 0, 0–2; DorsNap 1, 0–2; DorsPsag 1, 0–2; IngSpt 2, 0–2; HndlBr 2, 0–2; DlatSt 2, 1–2; Loreal 2, 0–2; LatTrnk 2, 0–2;
Chin
2, 0–2; Chest 1, 0–2. In summary,
K. interlineatus
usually has a faded to distinct middorsal stripe and no parasagittal stripes on head, distinct nape stripe in about half of the individuals continuing into bilateral (parasagittal) stripes, inguinal spot almost always present and usually as ocelli, dorsolateral narrow white stripe rarely absent or indistinct, hindlimbs almost always distinctly barred, loreal area and lateral trunk usually uniformly dark, chin and throat always dusky and usually with pair of darker longitudinal bars, and chest commonly dusky. Dorsal ground color is variable, ranging from a light beige or tan to medium or rufous brown, occasional individuals are rose to pink; sides from lore to inguinal are usually shades of medium to dark brown.
Fei et al. (2010)
provided color images of five living individuals whose dorsal coloration ranged from unicolor [
n
= 1 individual] to strongly patterned with all six of my dorsal pattern characters strongly developed [
n
= 5]. The dorsal stripe pattern of Chinese
K. interlineatus
has the same layout/arrangement; however, the stripes differ markedly in being broader with strongly scalloped edges and fragmented, especially the DorsPsag ones.
Karsen et al. (1986)
pictured a
Hong Kong
striped individual that matched those of Fei et al. Additionally Fei’s photographs showed well-developed white dorsolateral stripes that were strongly speculate in all individuals. The single individual depicted for
Cambodia
(Thy and Holden 2008) had a well-developed dorsal pattern similar to the western populations, although the white dorsolateral stripe was narrow and appeared interrupted. Ohler and Grosjean (2005) reported distinct pattern difference between “western” and Vietnamese frogs. The former depicted by a
Laos
individual (O&G 2005: figs. 1a,c,e) has straight-edged dorsal stripes, the latter (2005: figs. 1b,d,f) has the scalloped and fragmented stripes of the Chinese individuals. The preceding summary confirms Ohler’s and Grosjean’s observations of color pattern differences between west (
Thailand
) and east (
Vietnam
) and, as they noted, hints at the possibility of speciation between eastern and western populations. Chan and collaborators (2011) noted that half of their sample of Malaysian
K. interlineatus
(= their
pleurostigma
) lacked inguinal spots on one or both sides and concluded that “populations in Peninsular
Malaysia
are not conspecific” with mainland Asia populations. Their interpretation may be correct, although I suspect that there is no genetic discontinuity between these Malaysian population and those of peninsular
Myanmar
and
Thailand
.
ETYMOLOGY
.—
Blyth (1855)
offered no explanation for his name, presumably using
interlineatus
to note the longitudinal lines on the dorsum, hence a derivation from the Latin
inter
, between, and
lineatus
, from Latin
lineo
, drawing lines, and
linearis, lineatus
, of a line, linear.
DISTRIBUTION
.—
Kalophrynus interlineatus
as here defined has the broadest geographic range of the
pleurostigma
group, extending eastward from northern-most Peninsular
Myanmar
, eastward through northern
Thailand
,
Laos
,
Cambodia
, and
Vietnam
, southward through Peninsula
Malaysia
, and also in southern
China
from southeastern
Yunnan
to
Hong Kong
and adjacent Guangdong.
Bourret’s (1942)
concept of
K. interlineatus
was as a subspecies with a northern distribution from
Myanmar
through northern
Thailand
to
Vietnam
and adjacent
China
to
Hong Kong
. He had only a single male specimen (
38 mm
SVL
) of questionable locality (probably
Tonkin
,
Vietnam
) in Indochina. He listed four Burmese localities: Bhamo, Teinzo, Palon, Toungo (credited to Oates [Toungo] and Fea [diverse localities]). The first two records are potential localities for
K. anya
, the latter two are potential localities for
K. interlineatus
. Toungo (= Taungo,
20°56´N
95°24´E
) is in the upper Sittaung River valley.
MNHN
1893.492 is identified as
Kalophrynus interlineatus
from Palon; I did not examine this specimen to confirm its presence or identification. Palon (
7°41´N
97°31´E
), Kayin State, is identified as a Pegu locality in the British natural history museum specimen register but represented by only one gecko and one
Micryletta inornata
. This record highlights the broad geographic concept of Pegu by the British in late 19
th
century.
Thy and Holden (2008) stated that
K. interlineatus
was a common frog and suggested that it occurred throughout
Cambodia
.
NATURAL
HISTORY
.— In
Cambodia
, Thy and Holden (2008) reported it as a common species living in grassland, scrub forest adjacent to villages, and deciduous forest. The recent Burmese individuals derived from the soil surface in mixed deciduous-evergreen secondary growth forest (Mon) and from evergreen forest abutting a clear-cut (weedy) pipeline (Tanintharyi).
COMMENTS
.—
The
type
locality “Pegu” is commonly interpreted by biologists as equivalent to the present
Myanmar
division of
Bago
(formerly called
Pegu
).
Nineteenth
century
Pegu
encompassed a much broader area than the present political division.
The
older
Pegu
encompassed the area from the
Arkan
(roughly equivalent to the present state of
Rakhine
) eastward to the
Sittang River
drainage.
This
broad
Pegu
likely encompassed northernmost
Mon State
, hence my placement of the
type
locality straddling the
Bago-Mon
border.
This
broad
Pegu
is emphasized by a
NHMUK
/
BMNH
specimen from
Palon
,
Kayin state
, that was geographically labeled as
Pegu
.
Ohler and Grosjean (2005) reported examining the
holotype
of
Engystoma interlineatum
Blyth
, a specimen (
ZSI
9853) from Mergui,
Myanmar
. The British Museum has
two specimens
(
NHMUK
/
BMNH
68.4.3.128–129, recataloged as
1947.2.31.
26–27, an adult female and male, respectively) collected by Theobald in
Pegu
. I believe that the latter two
Pegu
specimens of Theobald’s (
Fig. 7
) are the individuals on which Blyth based his description of
interlineatum
, and they were subsequently sent to London. The precision of
ZSI
locality indicates that someone arbitrarily selected a
Kalophrynus
specimen and designated it as a
ZSI
holotype
. Mergui was never recognized as part of
Pegu
and is in Tenasserim. Because both
Blyth (1855:720)
and
Theobald (1882: 192)
specifically noted having
two specimens
, I recommend recognizing one of them as a
lectotype
and select
BMNH
1947.2.31.
26, the female, because this specimen is presently in the best physical condition.
BMNH
1947.2.31.
27 is then a
paralectotype
. Because
Pegu
is not sufficiently delimited, I recommend a more precise, yet not overly restrictive, type locality:
Bago
DivisionMon State border in the lower Sittaung River valley,
Myanmar
(~
17°35´24˝N
96°53´33˝E
).