Studies on the Development of the Labial Teeth Row Structure in Rana Curtipes Jerdon Tadpoles

7 Pages·2000·4.7 MB·

by  Jinesh James

STUDIES ON THE DEVELOPMENT OF THE LABIAL TEETH ROW STRUCTURE
IN RANA CURTIPESJERDONTADPOLES
1
JineshJames,ThomasT. Valamparampil2andOommenV. Oommen3
(With oneplate)
Key words: Rana curtipes, development, metamorphosis, labial teeth, tadpoles
Thedevelopmentofthe labial teethrowstructureofanurantadpolesofthetemperateregionshas
been studied. However, similar studies on tropical species are scant. The present study is an
attempt to describe the ontogeny ofthe labial teeth row structure ofRana curtipes an endemic
,
species ofthe Western Ghats ofIndia. R. curtipes tadpole has the highest reported number of
labia! teeth rows, with marginal teeth, among tropical frogs.
Introduction wereusedforthestudy.Freshlycollectedeggswere
dividedintogroupsof50andtransferredtoalarge
The teeth of frogs function primarily to aquarium(maintainedataphotoperiodof12L:12D
graspprey,ortopositionitforswallowing.Their at 29 ±2 °C) containing fresh pond water. After
distributionisknowntobevariableevenamong hatching,thetadpolesweredividedintogroupsof
closely related groups (Altig 1970). The oral 10 to avoid overcrowding, and reared in an
armature ofthe larvae differs from that of the aquarium ofthe same size (Group A). Waterwas
adults, as they differ in feeding habits. changedevery secondday, andthe tadpoles were
The ontogeny of the labial teeth row fedadlibitumwithboiledspinach.Thedeveloping
structure of anuran tadpoles inhabiting eggs and embryoswere observedunderbinocular
temperate regions has been studied by several microscopetonotemorphological changes atone
workers(Taylor 1942,Zweifel 1964,Altig 1970, hour intervals. Embryos and larvae were staged
Lee 1976, Webb and Korky 1977, Hero 1990 according to Gosner (1960) system for Rana
and Davies 1992). However, our knowledge of pipiens. Tadpolesofearlierstageswerepreserved
theIndianamphibiansisscant.Rao(1914),Lobo in 5% and later in 10% formaldehyde.
(1961), Chari (1962), Daniel (1975), Inger et Morphological features ofthe oral armature were
al. (1984) and Sekar (1990a) have given brief studied,andtheteethrowformulawasdetermined
notes on the mouth parts ofIndian amphibians. asperAltig(1970)modifiedbyWebbandKorky
Agarwal and Niazi (1980), and Dutta and (1977),tointroducethe“marginalteeth”.Tadpole
Mohanty-Hejmadi (1983) have reported the stages fromfeedingstage onwardswerecollected
ontogeny of the teeth row structure in Rana from a natural habitat near Thekkady (76° 50 'E,
tigerina (now Hoplobatrachus tigerinus). The 9° 45 'N), Kerala (Group B). Twenty to thirty
presentpaperdescribeschanges intheteethrow tadpoles were examined at each developmental
structure of Rana curtipes tadpoles during
stage.
metamorphosis.
Results
MaterialandMethods The number of teeth rows changed with
growth.Thetadpolescollectedfromswiftwaters
Fertilizedeggscollectedfromnaturalhabitat
(stream) had more teeth rows than those reared
‘AcceptedJuly,1999 in the aquarium. A list ofteeth row formulae of
3DepartmentofZoology,S.B.College, tadpoles rearedin the aquariumat29 ±2°C, and
Changanacherry,Kerala686101 India.
3DepartmentofZoology, Univers,ityofKerala,Karyavattom, those collected from a stream, have been
Thiruvananthapuram695581,Kerala,India. presented in Tables 1 and 2.
JOURNAL, BOMBAYNATURAL HISTORYSOCIETY, 97(2), AUG. 2000 223
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THELABIALTEETHROWSTRUCTUREIN RANACURTIPESJ£7?£>6W TADPOLES
Table1 Hatching and external gill stage: The
LABIALTEETHROWFORMULAOFRANACURTIPES
TADPOLES stomodaeum, at the anterio-ventral region, was
Stages GroupA GroupB a deep oval pit at the time of hatching. At the
Rearedinaquarium Collectedfrom external gill stage, it consisted ofa pair ofoval,
naturalhabitat black,non-serratedbeakswithoutlabialteethand
(stream) papillae. However, small indistinctridges could
Formula Percent Formula be seen on the lateral and ventral margins,
foreshadowing the labial teeth and papillae.
External
gillstage Withoutteeth Notcollected Oneexternalgillcoveredstage:Tadpoles
Oneexternalgill l/0/2(l) 53 Notcollected reached one gill covered stage with widened
coveredstage l/0/3(l) 47 mouth, and a single row ofpapillae on the sides
Operculum 1/0/20) 20 Notcollected ofthe upper and lowerjaws. The edges of the
completestage 2(2)/0/2(l 53 lower jaw had a single row of papillae, the
2(2)/0/3(l) 27
anterior edge ofthe upperjaw lacked papillae.
Feedingstage 3(3)/0/3(l) 59 3(3)/0/3(l)
Thebeaksbecameweaklyserrated.Atthisstage,
3(3)/0/4(l 41 3(3)/0/4(l)
53% of the tadpoles reared in the aquarium at
Prelimbstage 4(3-4)/0/4(l) 20 4(3-4)/0/4(l)
5(3-5)/0/4(l) 46 5(3-5)/0/4(l) 29±2°C, had ateethrow formulaofl/0/2(l)and
5(3-5)/0/5(l) 26 5(3-5)/1/5(1) 47%had l/0/3(1);withacombinedformulaof1/
5(3-5)/0/6(l 8 6(3-6)/l/6(l) 0/2-3(l) (Table 2). There was only one uninter-
Limbbudstage 5(3-5)/1/5(1 14 6(3-6)/l/6(l) rupted row in the upperjaw. The number varied
6(3-6)/0/6(l) 30 7(3-7)/2/6(l)
6(3-6)/l/6(l) 36 8(3-8)/3/7(l from 2 to 3 in the lowerjaw, the firstbeing inter-
7(3-7)/l/6(l) 20 8(3-8)/4/8(l) ruptedbyamedialgap.Marginalteethwereabsent.
9(3-9)/4/7(1 Operculumcompletestage: Atthisstage,
9(3-9)/4/8(l 20% of the tadpoles examined had l/0/2(l)
Footpaddlestage 7(3-7)/2/6(l 27 8(3-8)/3/7(l) (Table 1), 53% had 2(2)/0/2(l), and 27% had
7(3-7)/2/7(l 34 8(3-8)/4/8(l
8(3-8)/3/6(l) 39 9(3-9)/5/7(l 2(2)/0/3(l) formulae. The firstrow in the upper,
9(3-9)/5/8(l) and the secondandthird in the lowerjaw, when
10(3-10)/5/8(l) present, were uninterrupted. However, the first
Footstage 7(3-7)/2/7(1 22 8(3-8)/2/8(l row in the lower, and the second in the upper
8(3-8)/0/7(l) 56 9(3-9)/2/7(l) jaw, were centrally broken. In the majority of
8(3-8)/2/6(l) 22 9(3-9)/3/8(l)
9(3-9)/4/8(l) tadpoles, teeth in the two jaws were weakly
10(3-10)/3/8(l developed.Thecombinedteethrowformulawas
Welldeveloped 7(2-7)/0/7(l) 36 8(3-8)/0/7(l) 1-2(2)70/2-3(1).
hindlimbstage 8(3-8)/0/6(l 31 9(2-9)/0/8(l) Feeding stage: A single row of labial
8(2-8)/0/6(l) 33 9(3-9)/0/8(l)
papillaeappearedaroundthelateralandposterior
10(2-10)/1/8(1)
10(3-10)/l/8(l) marginoftheanterio-ventralmouth. Thesecond
Oneforelimbstage 7(1-7)/0/4(1 61 9(3-9)/0/6(1 continuousrowofteethintheupperjawappeared
8(2-8)/0/6(l) 39 8(2-8)/0/7(l) for the first time. The third and fourth rows of
7(1-7)/0/6(1 ventral jaw were poorly developed; marginal
Bothlimband 5(1-5)/0/3(1-3) 8 5(1-5)/0/3(l-3) teeth were not present at this stage. The teeth
tailstage 4(1-4)/0/3(l-3) 32 4(1-4)/0/2(1-2) row formula varied from 3(3)/0/3(l) to 3(3)/0/
4(1-4)/0/2(l-2) 33 3(1-3)/0/3(1-3
3(1-3)/0/2(1-2 27 4(1), in two groups of tadpoles, and thus the
combined formula 3(3)/0/3-4(l) was the same
Frogletstage Withoutlabial Withoutlabial
forboth groups.
teeth teeth
224 JOURNAL, BOMBAYNATURAL HISTORYSOCIETY. 97(2), AUG. 2000

THELABIALTEETHROWSTRUCTUREIN RANACURTIPESJERDON TADPOLES
James, Jinesh etal.: Rana curtipes Plate 1
Fig. 1: a. Mouth parts ofatadpoleofRana curtipes atfootpaddle stage (stage 34).
b. Marginal teeth ofatadpole ofR. curtipes atfootpaddle stage (stage 34).
LT-labial teeth, MT-marginal teeth.
226 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 97(2), AUG. 2000
) ) ) )))))
THELABIALTEETHROWSTRUCTUREIN RANACURTIPESJERDON TADPOLES
Table 2
COMBINEDLABIALTEETHROWFORMULAOFRANACURTIPESTADPOLES
Stages GroupA GroupB Generalcombined
Rearedinaquarium Collectedfrom formula
naturalhabitat(stream
Externalgillstage Withoutteeth Notcollected Nil
Oneexternalgillcoveredstage l/0/2-3(l) Notcollected l/0/2-3(l)
Operculumcompletestage l-2(2)/0/2-3(l) Notcollected l-2(2)/0/2-3(l
Feedingstage 3(3)/0/3-4(l) 3(3)/0/3-4(l) 3(3)/0/3-4(l)
Prelimbstage 4-5(3-5)/0/4-6(l) 4-6(3-6)/0-l/4-6(l) 4-6(3-6)/0-l/4-6(l
Limbbudstage 5-7(3-7)/0-1/5-60) 6-9(3-9)/l-4/6-8(l) 5-9(3-9)/0-4/5-8(1
Footpaddlestage 7-8(3-8)/2-3/6-70) 8-10(3-10)/3-5/7-8(l) 7-10(3-10)/2-5/6-8(
1
Footstage 7-8(3-8)/0-2/6-7(l 8-10(3-10)/2-4/7-8(l) 7-10(3-10)/0-4/6-8(l
Welldevelopedbindlimbstage 7-8(2-8)/0/6-7(l) 8-10(2-10)/0-l/7-8(l) 7-10(2-10)/0-l/6-8(l
Oneforelimbstage 7-8(1-8)/0/4-6(l) 7-9(1-9)/0/6-7(l) 7-9(1-9)/0/4-7(l)
Bothlimbandtailstage 3-5(1-5)/0/2-3(1-3) 3-5(l-5)/0/2-3(l-3) 3-5(1-5)/0/2-3(l-3)
Frogletstage Nil Nil Nil
Prelimbstage: Theteethrowformulae of 7(3-7)/1/6(1) labial teeth row formulae. Group
the tadpoles reared at 29 ±2 °C were 20% 4(3- B tadpoles varied widely in the number ofteeth
4)/0/4(l), 46% 5(3-5)/0/4(l), 26% 5(3-5)/0/5(l) rowsatthisstage(Table 1).Onerowofmarginal
and 8% 5(3-5)/0/6(l). The lastrow ofthe lower teethappearedforthefirsttimeintadpolesreared
jawin70%ofthetadpoleswaspoorlydeveloped. in the aquarium. Another characteristic was the
The combined formula 4-5(3-5)/0/4-6(l) developmentoftwotothreerowsofsub-marginal
indicated that, of4 to 5 rows in the upperjaw, papillaeonthesidesofbothjaws.Thelowerand
the first two rows were uninterrupted, marginal upper beaks were strong, serrated and
teeth were absent and in the lowerjaw the teeth keratinized. As in some ofthe previous stages,
rows varied from 4 to 6, with the first row the last row oflabial teeth in the lowerjaw was
uninterrupted.Tworowsofsubmarginalpapillae poorlydeveloped, orincomplete. The combined
couldbeseenonthesidesoftheupperandlower teeth row formula was 5-7 (3-7)/0-l/5-6(l) in
jaws. Group A and 6-9(3-9)/l-4/6-8(1) in Group B.
The combined teeth row formula, 4-5 Foot paddle stage: The combined teeth
(3-5)/0/4-6(l), of tadpoles reared in the lab rowformulaeofGroupA [7-8 (3-8)/2-3/6-7(1)]
indicatesthepresenceofamaximumoffiverows and Group B [8-10(3-10)/3-5/7-8(1)] indicated
in the upperjaw and six rows in the lowerjaw. that maximum upper labial, lower labial and
The combined teeth row formula of tadpoles marginal teethappeared forthe firsttime in this
collected from the stream was 4-6(3-6)/0-l/4- stage. Maximum upper labial teeth rows in
6(1). One row of marginal teeth was observed GroupA were 8 and in Group B10. Similarly,
for the first time in 40% ofthe tadpoles. the maximum marginal teeth rows observed in
Limb bud stage: In this stage of Group A were 3. In Group B, the minimum and
development, Group A had 14% 5(3-5)/l/5(l), maximum marginal teeth rows were 3 and 5
30% 6(3-6)/0/6(l), 36% 6(3-6)/l/6(l) and 20% respectively (Plate 1). All the rows ofteeth in
JOURNAL, BOMBAYNATURAL HISTORYSOCIETY, 97(2), AUG. 2000 227
THELABIALTEETHROWSTRUCTUREIN RANACURTIPESJERDON TADPOLES
the upper and the lower jaws were well lateralsidesofmouthinthepreviousstages,were
developed. absorbedandpapillaewereseeninsmallclusters
Footstage: InGroupAtadpoles,22%had at the comers of the mouth. The homy beaks
7(3-7)/2/7(l), 56% had 8(3-8)/0/7(l) and the disappeared. The mouth widened, and the
remaining 22% had 8(3-8)/2/6(l) formulae. comersreachedtheleveloftheposteriormargin
Thus, 78% oftadpoles ofGroup A at this stage ofthe eyes.
had 8 rows in the upperjaw. Another feature at
this stage was the reduction in marginal teeth. Discussion
56% in Group A had completely lost their
marginal teeth. Likewise, in Group B, the The present study shows that there are
majority had less than 4 rows ofmarginal teeth. variations inthedevelopmentoflabialteethrow
Acomparisonbetweenfootpaddleandfoot structureintropicalanurans.Thenumberofteeth
stages indicates thatwhile there was an increase rowschangeswiththestageofdevelopment,and
in the percentage oflabial teeth row number in for each stage there are individual variations.
foot stage, a decrease in marginal teeth row Table 1 indicates that labial teeth appear at the
numberalso occurredinbothgroups oftadpoles one external gill covered stage, and reach a full
at the foot stage. complement of rows at the foot paddle stage.
Well developed hindlimb stage: All the Labialteeth rowsmaintainthis full complement
tadpoles ofGroup A and a number oftadpoles up tothewell-developedhindlimb stage. Before
inGroupB hadlosttheirmarginal teeth. Second the onset of metamorphosis, labial teeth begin
labial teeth row became broken in 69% of to shed and disappear with the completion of
tadpoles. Thus, reduction or shedding oflabial metamorphosis. Dutta and Mohanty-Hejmadi
teeth had started at this stage. None of the (1983)reportedasimilarpatterninRanatigerinci
tadpoles hadthe full complementofteeth atthis (now Hoplobatrachus tigerinus). Further, the
stage. present study shows that the teeth rows in the
One forelimb stage: Teeth row formula upperjawvaryfrom 1 to 10. Similarly, thelabial
varied from 7(1-7)/0/4(1) to 8(2-8)/0/6(l) in teethrows inthelowerjawvaryfrom2 to 8. The
Group A tadpoles. The combined formula of combined teeth row formula for Rana curtipes
Group B was 7-9(l-9)/0/6-7(l). In the majority according to Rao (1914) is 6-8(4-8)/6-8(l), and
of tadpoles, both upper and lower jaw had Sekar (1990b) is 7(3-7)/5-8(l) or 7(4-7)/5-8(l).
intermittently broken labial teeth rows. The The present observation agrees with the views
sheddingoflabialteethhadalready startedprior of Rao (1914) and Sekar (1990b) in the
to this stage. The rows ofsub-marginal papillae maximumnumberofrowsandnatureofthefirst
were absorbed, and limited to the comers ofthe row inthe lowerjaw.
mouth. The number ofpapillae decreased in the The present study established that Rana
lower jaw. The horny beaks, both upper and curtipes tadpoles have marginal teeth, which
lower, became thick, colourless orwhite, except make their first appearance in the prelimb stage
atthe edges where they wereblack atthis stage. (Table 2), reach a maximum at the foot paddle
Both limb and tail stage: In both groups stage, and begin to disappear at the foot stage.
oftadpoles,thecombinedteethrowformulawas Thenumberofmarginal teethvaries from0 to 5
the same, 3-5(l-5)/0/2-3(l-3). All the rows in in Rana curtipes. Similar findings have been
the upper and lowerjaws were interrupted with reported in R. pustulosa (Taylor 1942), R.
lostteeth,andlimitedtothecomersofthemouth. tarahumarae(Zweifel 1955)andR. macroglossa
The labial fringes, which were present on the (VolpeandHarvey 1958).Butnonehavereported
228 JOURNAL BOMBAYNATURAL HISTORYSOCIETY. 97(2). AUG. 2000
THELABIALTEETHROWSTRUCTUREIN RANACURTIPESJERDON TADPOLES
thepresenceofmarginalteethinatropicalanuran. Indirana beddomii) [4(4)/0/4(1-2)] and
Some differences were also found in the R. keralensis (now Limnonectes keralensis)
number ofteeth rows between aquarium reared [2(2)/0/3], by Chari (1962) for R. malabarica
tadpoles, and those collected from their natural [170/2(1)] andbySekar(1990b)forRhacophorus
stream habitat. The tadpoles developed in the malabaricus [6(3-6)/0/3(1)], werelessthanthose
aquariumdiffersignificantlyfromthosecollected of Rana curtipes. The maximum number
from streams in the number, pattern and reported for R.tigerina (now Hoplobatrachus
percentage ofoccurrence oflabial andmarginal tigerinus), by Dutta and Mohanty-Hejmadi
teeth rows. In Rana curtipes 10 rows oflabial (1983), was 5(2-5)/0/(l-3).
,
teeth in the upper and 8 rows in lower jaw The above observations reveal that Rana
indicate that the species has the largest number curtipes has the largest number of labial teeth
oflabialteethrows amongtropical frogs. Labial rows among tropical anurans and the number
teethrowformulaereportedbyIngeretal. (1984) ofteeth rows changes with the development of
forR. temporalis [2(2)/0/2(1)],R. beddomi(now tadpoles.
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