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Rediscovering the Apaporis Caiman (Caiman crocodilus apaporiensis): Notes from a Long-Anticipated Expedition

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Caiman crocodilus apaporiensis has been of particular interest because of its clearly differentiated morphotype within the Spectacled Caiman complex. Information on the biology of C. c. apaporiensis is incomplete because of its restricted distribution in the inaccessible middle and upper Apaporis River in Colombia. I undertook an expedition to the middle Apaporis River basin in an attempt to validate the presence of C. c. apaporiensis through observations on morphometry, ecology, and ethnozoology. Previously described skull characteristics were clearly differentiable in both adults and subadults in the region. However, because many individual C. c. apaporiensis that were either captured or visually assessed were relatively small, some skull characteristics more closely resembled the more general C. crocodilus morphotype. Although data on population size and distribution of C. c. apaporiensis remain limited, information gleaned from local inhabitants indicates that the subspecies is common in the middle Apaporis River. Population parameter and molecular phylogeography studies could lead to management practices that would protect the genetic integrity of C. c. apaporiensis by minimizing subspecific interbreeding.
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Rediscovering the Apaporis Caiman (Caiman crocodilus apaporiensis): Notes
from a Long-Anticipated Expedition
Author: Sergio A. Balaguera-Reina
Source: Journal of Herpetology, 53(4) : 310-315
Published By: Society for the Study of Amphibians and Reptiles
URL: https://doi.org/10.1670/19-028
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Journal of Herpetology, Vol. 53, No. 4, 310–315, 2019
Copyright 2019 Society for the Study of Amphibians and Reptiles
Rediscovering the Apaporis Caiman (Caiman crocodilus apaporiensis): Notes from a
Long-Anticipated Expedition
SERGIO A. BALAGUERA-REINA
Programa de Biologı´a Ambiental, Facultad de Ciencias Naturales y Matema´ticas, Universidad de Ibague´, Carrera 22 Calle 67, Ibague´ 730001, Colombia, and
Department of Biological Sciences, Texas Tech University, Lubbock, Texas, 79409, USA; E-mail: sergio.balaguera@unibague.edu.co, otto122@gmail.com
ABSTRACT.—Caiman crocodilus apaporiensis has been of particular interest because of its clearly differentiated morphotype within the
Spectacled Caiman complex. Information on the biology of C. c. apaporiensis is incomplete because of its restricted distribution in the
inaccessible middle and upper Apaporis River in Colombia. I undertook an expedition to the middle Apaporis River basin in an attempt
to validate the presence of C. c. apaporiensis through observations on morphometry, ecology, and ethnozoology. Previously described
skull characteristics were clearly differentiable in both adults and subadults in the region. However, because many individual C. c.
apaporiensis that were either captured or visually assessed were relatively small, some skull characteristics more closely resembled the
more general C. crocodilus morphotype. Although data on population size and distribution of C. c. apaporiensis remain limited,
information gleaned from local inhabitants indicates that the subspecies is common in the middle Apaporis River. Population parameter
and molecular phylogeography studies could lead to management practices that would protect the genetic integrity of C. c. apaporiensis
by minimizing subspecific interbreeding.
RESUMEN.—Caiman crocodilus apaporiensis ha sido de particular intere´s debido a que su morfolo´a esta´ claramente diferenciada
dentro del complejo de los caimanes de anteojos. La informaci ´
on en la biologı´a del C. c. apaporiensis esta incompleta debido a su
distribuci ´
on restringida en la regi ´
on media y superior del inaccesible rio Apaporis en Colombia. Emprendı´ una exploraci ´
on a la cuenca de
la regi ´
on media del rio Apaporis en un intento de validar la presencia del C. c. apaporiensis atrave´s de observaciones de morfometrı´a,
ecologı´a, y etno-zoologı´a. Las caracterı´sticas del cra´ neo descritas por Medem (1955) fueron claramente diferenciables en ambos adultos y
sub-adultos de la regi ´
on. Sin embargo, debido a que muchos de los C. c. apaporiensis que fueron capturados fueron relativamente
pequen˜os algunas de las caracterı´sticas craneales fueron ma´ s cercanas a la morfolo´a general del C. crocodilus. Aunque los datos de
poblaci ´
on y distribuci ´
on del C. c. apaporiensis permanecen limitados, la informaci ´
on recabada de los pobladores indica que la subespecie
es com ´
un a la mitad del rio Apaporis. Estudios sobre para´ metros de la poblaci ´
on y filogeografı´a molecular pueden concluir en practicas de
control que puedan proteger la integridad gene´tica de C. c. apaporiensis al minimizar la cruza dentro de la subespecie.
Colombia is one of the most biodiverse countries in the world
(Jenkins, 2003), as exemplified by the six species of crocodilians,
including three subspecies of the Spectacled Caiman (Caiman
crocodilus; Medem, 1981). However, information on the natural
history, distribution, and dynamic ranges of each of the
Colombian crocodilian species is scant to nonexistent (Mo-
rales-Betancourt et al., 2013; Balaguera-Reina et al., 2015a).
The Spectacled Caiman (C. crocodilus) has one of the broadest
distributions of all crocodilians, ranging from Mexico to Peru and
Brazil, with successful introductions by humans in the United
States (Florida), Cuba, and Puerto Rico (Velasco and Balaguera-
Reina, 2019). Caiman crocodilus has also been introduced into the
insular areas of San Andres and Gorgona Islands in Colombia
(Medem, 1981; Forero-Medina et al., 2006), with little to no
assessment of the ecological impacts on native species.
Morphological and genetic studies on C. crocodilus complex
have demonstrated considerable variability across its range,
supporting the recognition of at least four subspecies: C. c.
fuscus,C. c. crocodilus,C. c. chiapasius, and C. c. apaporiensis
(Medem, 1955, 1981; King and Burke, 1989; Busack and Pandya,
2001; Amato and Gatesby, 1994; Venegas-Anaya et al., 2008;
Escobedo-Galva´n et al., 2015). Caiman c. fuscus and C. c.
crocodilus are widely distributed in Central and South America,
whereas C. c. chiapasius and C. c. apaporiensis have more
restricted distributions (former: from Chiapas, Mexico to El
Salvador [Venegas-Anaya et al., 2008]; latter: endemic to the
middle and upper Apaporis River basins in Colombia [Medem,
1981]).
The Apaporis Caiman (C. c. apaporiensis) has been of
particular interest since being collected by Medem in 1952 and
described in 1955 (=C. sclerops apaporiensis) because of its easily
differentiated morphotype (narrow snouted) within the Specta-
cled Caiman complex (Medem, 1955, 1981; Escobedo-Galvan et
al., 2015). The restricted distribution of C. c. apaporiensis and the
relative inaccessibility to middle and upper Apaporis River
basins to researchers due to protracted Colombian political
unrest have resulted in a paucity of research on this subspecies
for over 40 yr. A single published survey after Medem’s (1955)
work was conducted in the Apaporis River, recording 497
individuals across 11 areas in one-single-visit spotlight survey
(Naranjo, 1996; Rodriguez, 2000). However, only 42 individuals
were classified as C. c. apaporiensis, with 455 assigned to C. c.
crocodilus, lending to the uncertainty of both the presence and
conservation status of this endemic subspecies in the area. Thus,
clarifying the conservation and taxonomic status of the
Apaporis Caiman has become a prodigious challenge among
crocodilian biologists worldwide and was identified by the
International Union for Conservation of Nature/Species Sur-
vival Commission (IUCN/SSC)/Crocodile Specialist Group as
an issue in urgent need of resolution (Velasco and Balaguera-
Reina, 2019).
On the basis of starch gel electrophoretic analyses of blood
proteins from a single, alleged C. c. apaporiensis at the Cincinnati
Zoo, Densmore (1983) found this animal to be the most distinct
of all of the three C. crocodilus representatives that he sampled
(all but C. c. chiapasius). However, despite its unusual
appearance (extended snout), the absolute identity or origin of
the zoo specimen has never been verified. Some recent efforts to
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resolve the Apaporis Caiman taxonomic status genetically
(Bloor, 2013) and morphologically (Escobedo-Galvan et al.,
2015) during the last decade have failed because of the lack of
sufficient sample sizes and deoxyribonucleic acid (DNA) quality
(i.e., they extracted DNA from paratype skulls collected by
Medem in the 1950s), thereby limiting possible conclusions that
could be made. Recent debates among scientists regarding C. c.
apaporiensis taxonomic validity and its uncertain conservation
status have emphasized the need to resample the middle and
upper Apaporis River basins that were studied by Medem
(1955) to identify the distribution of potential subspecies.
Herein, I present results of an expedition carried out to the
middle Apaporis River basin to validate the presence of the
subspecies described by Medem (1955) with notes regarding its
ecology, ethnozoology, conservation, and possible future re-
search.
MATERIALS AND METHODS
Study Area.—The 1,060-km Apaporis River courses through
four departments (Guaviare, Caqueta´,Vaupe´s, and Amazonas) in
Colombia before emptying into the Caqueta´River(alsoknownas
Japura River; IDEAM et al., 2007). The Apaporis River originates
at the junction of the Tunia and the Ajaj ´u rivers at the Dos Rios
locality (between Caqueta´ and Guaviare departments) and flows
480 km until reaching the most prominent of its waterfalls, the
Jirijirimo waterfall, which acts as a zoogeographic barrier for
aquatic organisms (Medem, 1981). As a whitewater river, the
highly productive Apaporis River has high levels of suspended
sediments that result in near-neutral pH, high conductivity, and a
pale, muddy color (Sioli, 1984). The Apaporis River flows past
abandoned oxbows that may contain stagnant black waters that
are seasonally connected to the main river.
Fieldwork.—I carried out an expedition to the middle Apaporis
River basin between the Vaupes and Amazonas departments on
8–16 December 2018 (Fig. 1). I sampled five areas that included
the Inana, Churuco, and Arriba lagoons and two segments of the
Apaporis River between La Victoria and Inana lagoons and
between Inana and Churuco lagoons (Fig. 1). At night, I carried
out spotlight surveys (Chabreck, 1963) using handcrafted canoes
and a 5,000-lumen headlamp (InnoGear 5000 LED, Morgan Hill,
California) with assistance from two indigenous people who
powered the canoe with paddles. During the day, I interviewed
indigenous people to gain insights into the potential uses of, and
beliefs associated with, C. c. apaporiensis and into conflicts
FIG. 1. Study area highlighting the potential distribution area for Caiman crocodilus apaporiensis and all individuals seen across the five transects
followed at the middle Apaporis River basin, Colombia.
REDISCOVERING THE APAPORIS CAIMAN 311
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between humans and the Apaporis Caiman and other crocodilian
species in the region. We did not collect personal information that
would reveal an interviewee’s identity and data derived from
interviews were kept anonymous in the analyses.
Night surveys were conducted between 1900 and 0400 h
along transects established in the five areas (Fig. 1, Table 1).
When an animal was visually located, I recorded location and
approached as close as possible to record morphological
features (relative snout width) as well as to estimate total
length (TL) and to obtain photographs. When possible, I
captured the animal by a noose with catch poles, individually
marked it by scale clipping, sexed it, and collected several
morphological measurements (snout–vent length [SVL], TL,
total head length, cephalic plate length, head height, fourth
maxillary tooth width, fourth mandibular tooth width, and
mass). In the case of animals where TL was estimated visually,
individuals were grouped by size classes as recommended by
Ayarzagu¨ ena (1983) for C. c. crocodilus as follows: classes I (<50
cm), II (50–120 cm), III (121–180 cm), and IV (>180 cm). Each of
the five study areas was sampled once and captured animals
were released immediately after the collection of data. Descrip-
tive statistical and morphological data were analyzed via R 3.5.2
(R Development Core Team, 2012). Finally, a first approximation
of C. c. apaporiensis distribution map was accomplished using
ArcGIS 10.6 (ESRI, 2017) on the basis of the IUCN Red List
protocol using hydroSHEDS (Lehner et al., 2008; IUCN, 2012).
RESULTS
A total of 105 C. c. apaporiensis and 1 Paleosuchus palpebrosus
were recorded across the five surveyed areas (Figs. 1, 2) and of
these, 69 were registered as eyes only—without a TL estimate—
and 17 individuals were captured with the full complement of
measurements obtained. The TLs of 19 individuals were
estimated only visually without capture and were grouped as
class II (10 individuals), class III (seven individuals), and class
IV (two individuals). A size class analysis including all animals,
both captured and sighted, for whom TL was estimated (N=
37) showed a large number of juveniles (class II) and few adults
(class IV) across the study area (Fig. 3).
Laguna Arriba had the highest number of C. c. apaporiensis
recorded (55 individuals; Table 1) and was the only site with a
record of P. palpebrosus. Churuco and Inana´ lagoons had
intermediate numbers of C. c. apaporiensis (24 and 17 individ-
uals, respectively). The river segments, Victoria-Inana´and
Inana´ -Churuco, had lower numbers (seven and two individuals,
respectively), with no presence of P. palpebrosus. The relative
abundance estimates for transects visited were 8.21 individu-
als/km in Laguna Arriba, 6.15 individuals/km in Churuco
Lagoon, 4.86 individuals/km in Inana´ Lagoon, 1.84 individu-
als/km in the La Victoria–Inana´ River segment, and 0.25
individuals/km in the Inana´–Churuco River segment (Table 1).
Captured animals had TL and SVL measurements averaging
68.5 642.2 cm and 35.1 622.3 cm, respectively, with a mean
body mass of 3 kg (min.–max. =0.09–27.8 kg; Table 2). One
individual captured at the Inana´-Churuco River segment was
not included in this descriptive analysis because it did not have
the single-crested part of the tail, a condition that appeared to be
genetic or developmental rather than a mutilation caused by
another animal. Seven individuals were males, three were
females, and seven were of undetermined sex. Five of the latter
animals were observed at a single location in the Arriba Lagoon
with TL between 35 and 40 cm (i.e., yearlings; Table 2).
On the basis of the historically reported ranges of C. c.
apaporiensis (Medem 1955, 1981; Naranjo, 1996) plus those
collected in the present study, I estimate the distribution area of
the C. c. apaporiensis to be 12,640 km
2
, covering a total of 14
watersheds across the upper and middle Apaporis River,
including the lower Ajaj ´u, Tunia, Mecaya, and Tucunema river
basins (Fig. 1).
Ethnozoology.—I interviewed 11 indigenous people (all adults
>30 yr old) from La Victoria community (total population =96;
Appendix 1). All were born in the area and were members of the
various indigenous tribes (Barasano, Cubeo, Tatuyo, Carapana,
Cabiyari, Yucuna, Carijonas, and Tucanos, among others). The
local indigenous people recognized three crocodilian species, or
‘cachirres,’’ in the area: two darkly colored species (‘‘cachirres
negros’’; Paleosuchus trigonatus and P. palpebrosus) and one more
lightly colored species (‘‘cachirre blanco’’; C. c. apaporiensis). Most
indigenous communities in the area preferred to eat black over
white cachirres. People of only three tribes consume white
cachirres (Barasanos, Macunas, and Letuamas), with most of
these individuals inhabiting one nearby community (Mu-
tanacua). Other tribes, especially those living in La Victoria, do
not use white cachirres as a food source because of either
religious beliefs (white cachirres represent condemned men),
tradition as dictated by elders, or because of bad taste with a
slimy nature to the meat. Only 2 of the 11 individuals interviewed
TABLE 1. Transects sampled across the middle Apaporis River basin
and some lagoons around this area. Inana´ and Churuco lagoons were
the areas sampled by Medem (1955).
Transect name
Transect
length
(km)
No. of
Caiman crocodilus
apaporiensis
Relative
abundance
(individuals/km)
La Victoria–Inana´
(Apaporis River
segment)
3.8 7 1.84
Inana´ –Churuco
(Apaporis River
segment)
8.1 2 0.25
Laguna Arriba 6.7 55 8.21
Churuco Lagoon 3.9 24 6.15
Inana´ Lagoon 3.5 17 4.86
Total 26 105
FIG. 2. Heads of Caiman crocodilus apaporiensis captured in the middle
Apaporis River basin, Colombia. Scales on each side and labels
represent the total head length (THL) in centimeters of each animal
depicted. 4MTW, fourth mandibular tooth width; 4XTW, fourth
maxillary tooth width; CPL, cephalic plate length.
312 SERGIO A. BALAGUERA-REINA
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reported hunting white cachirres and using them as bait or to
feed hunting dogs.
My interviews indicated that December is the primary mating
season for white cachirres, with eggs laid in January and
hatching occurring between March and April. The individuals
reported that white cachirres are abundant in lagoons and
closed water bodies, with lower densities in the flowing rivers
and open areas. In contrast, black cachirres were considered to
be scarce across all areas, likely caused by excessive use by
humans.
On the basis of my interviews, hunting that focused on
acquiring white cachirres skins came to the area in the mid-
1960s when rubber tappers (mainly foreigners) started to buy
skins from the local people. The most valuable skins at the time
were jaguar, ocelot, otter, and white cachirres. Hunting pressure
ceased in the 1980s when the profitable coca fields (Erythrox-
ylum coca) were established in the area.
DISCUSSION
I verified the presence of the Apaporis River caiman in five
areas where Medem (1955) described the subspecies for the first
time in the middle basin of the Apaporis River, with no
sightings of any other C. c. crocodilus morphotypes. My
corroboration of the subspecies was based on both skull
(comparatively narrow snout and flat cranial table) and external
morphology (bright yellow-brownish color spotted with black
vermiculations) as described by Medem (1955). The observation
is highly relevant because Naranjo (1996) reported a high
proportion of animals with C. c. crocodilus morphotype and
Medem (1981) hypothesized that C. c. crocodilus was colonizing
the upper Apaporis River basin in the 1970s as a result of
hunting pressure in the Caqueta River. One singular feature
found in animals captured in the present study, and also by
Medem (1955), was the presence of several orange-colored
scutes on the side of the neck that have not been reported in any
TABLE 2. Morphometric variables measured for all individuals captured across transects in the middle Apaporis River basin: snout–vent length
(SVL), total length (TL), total head length (THL), cephalic plate length (CPL), head height (HH), fourth maxillary tooth width (4XTW), fourth
mandibular tooth width (4MTW).
Identification SVL (cm) TL (cm) THL (cm) CPL (cm) HH (cm) 4XTW (cm) 4MTW (cm) Weight (kg)
2 40 75 10.8 4 4 4
4 28 59 8 3 3 3 2 0.61
5 38.5 68.5 10 5 3.5 3.5 2.6 1
6 31.6 64 9.2 4.3 3.2 3.2 2.5 0.8
8 39 78.8 10.8 4 3.9 4 2.6 1.47
9 17.5 35.2 5.3 2.4 2.3 2.3 2 0.09
10 59 116 16.2 5 5.2 5.2 3.7 4.79
11 45 85 12.8 4.5 4.2 4.5 3.3 2.56
12 102 195 27.2 8.3 9.8 10 5.6 27.8
13 65 127 17.5 6 7 6 4.2 7.39
14 16.4 35 5 2 2 1.8 1.4 0.16
15 17.6 36.8 5.3 2.9 2 2.7 1.4 0.17
16 19 40 5.5 2.5 2.3 2.6 1.5 0.17
17 17 36.5 5 2.4 2 1.8 1.3 0.12
18 16.8 36 5.2 2.2 2 2.3 1.3 0.21
19 16.8 35 5.3 2.4 2.1 1.7 1.3 0.1
Mean 35.58 70.18 9.94 3.81 3.66 3.66 2.45 3.16
SD 22.87 42.88 5.94 1.65 2.08 2.03 1.23 6.89
Max. 102 195 27.2 8.3 9.8 10 5.6 27.8
Min. 16.4 35 5 2 2 1.7 1.3 0.09
FIG. 3. Size class analysis depicting the proportions of juveniles and subadults (classes I and II) compared with reproductively mature animals
(classes III and IV). Given the life history of crocodilians with a type III survivorship curve (low proportion of individuals surviving in the first stages
of life; Milnes and Guillette, 2008), one should expect a large number of adults and fewer juveniles in a nonaffected population.
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other subspecies of the C. crocodilus complex. One possible
explanation of orange-colored scutes could be discoloring due
to exposure to iron or other chemicals that can stain the skin.
Skull characteristics described by Medem (1955) as unique in
Apaporis Caimans were clearly differentiable in both adults and
subadults (Fig. 2). However, as many animals captured or
spotted visually were smaller (i.e., juveniles and yearlings),
skull characteristics more closely resembled the more general C.
crocodilus morphotype, an observation also made by Medem
(1955). The young C. c. apaporiensis with C. crocodilus morpho-
type features could explain the high number of C. c. crocodilus
reported by Naranjo (1996). Therefore, C. c. crocodilus may not
actually occur in the area. Genetic analyses are ongoing to fully
clarify the phylogeographic relationship between C. c. apapor-
iensis and C. c. crocodilus because of the significant variation in
skull dimensions (narrow snout vs. broad snout) that has been
reported for C. c. crocodilus across its range (Ayarzagu¨ ena, 1983;
Gorzula, 1994; Ayarzagu¨ ena and Castroviejo, 2008).
All individuals over the range of body sizes were very wary
of humans across all areas surveyed, with the exception of
Laguna Arriba, likely reflecting some type of hunting pressure
in these other localities. A ‘‘hunting-induced wariness’’ hypoth-
esis was supported by locals who reported that some tribes in
the area consume Apaporis Caimans. A size class analysis was
consistent with the hypothesis in that there were a large
proportion of juveniles and very few adults present in the
samples (Fig. 3). Given the life and reproductive history of
crocodilians (type III survivorship curve, with low proportion of
individuals surviving in the first stages of life; Milnes and
Guillette, 2008), one should expect a large number of adults and
fewer juveniles in a nonaffected population. Even though C. c.
apaporiensis is adapted to endure high mortality in early ages
and low mortality in the older ones, high hunting pressure in
adults could put populations at risk.
The largest male and female C. c. apaporiensis captured in my
study were 195 cm and 85 cm TL, respectively, which contrasts
with the maximum sizes reported for the subspecies across the
upper and middle Apaporis River basins (222 cm TL for males
and 173 cm TL for females; Medem, 1981). Observed differences
between my study and that of Medem (1981) could be
influenced by variables such as the reproductive patterns of
the species as well as environmental features such as precipi-
tation and temperature (Brien et al. 2008; Balaguera-Reina et al.,
2016). The reproductive ecology of the Apaporis Caiman is
poorly understood and many of the descriptions are based on
data collected by third parties (i.e., local people). Only Medem
(1981) reported a partially constructed nest in March, 1952 at the
Inana´ Lagoon. The observation of five putative yearlings (TL
~35–40 cm), grouped at the same place in the Laguna Arriba,
likely indicates the presence of a nesting area in the vicinity.
Medem (1955) described the distribution of this subspecies to
range between Yaviya Port (rubber camp) and Jirijirimo
Waterfalls, indicating that it was somewhere around 200 km.
The distribution of the subspecies was later expanded upon
finding the Apaporis Caiman at the Ajaju River mouth where
the Apaporis River is born (Medem, 1981). On the basis of these
data and using the Red List range protocol (IUCN, 2012), I
estimate a total distribution area of 12,640 km
2
for the
subspecies (Fig. 1). Even though this approximation may
overestimate the actual range of the subspecies (because of the
inclusion of uninhabitable areas), it provides an initial spatial
analysis that can be used as the null hypothesis to test in future
studies. It also strongly implies that more expeditions to the
upper and middle Apaporis River basins must be undertaken to
clarify the actual range of C. c. apaporiensis on the basis of more
robust analyses (e.g., species distribution models).
Although the number of scientific expeditions to the region
has been comparatively low and the population size and range
of the subspecies remain largely unknown, data reported by
researchers and locals seem to suggest that the subspecies is
common in the middle Apaporis River. The persistence of
morphotype is critical because of the necessity of taxonomically
clarifying its status. Scientific efforts must be directed at the
upper Apaporis River basin to assess population parameters
(growth, demographics, densities, spatial dynamics) as well as
the phylogeography of the subspecies because of the possibility
of subspecific intergradations (e.g., C. c. crocodilus with C. c.
apaporiensis), which could be to the detriment of C. c. apaporiensis
genetic integrity. Ultimately, detailed information on the biology
of C. crocodilus in the region will aid in resolving the subspecific
vs. specific status. Finaly, a clear definition of the conservation
status of the subspecies will allow government agencies to
facilitate the passing of up-to-date legislation to preserve and
sustainably use the Apaporis Caiman.
Acknowledgments.—My project was sponsored by the Univer-
sity of Ibague, Texas Tech University, IUCN/SSC/Crocodile
Specialist Group, CrocFest, and CrocDocs and was approved by
the University of Ibague research center (18-489-ESP) to capture
Apaporis Caimans and collect samples under its national
permit. I thank Alfredo Vargas-Carapana and his family for
hosting me and helping me to navigate and explore the
Apaporis River ecosystems and cultures. I also thank Lou
Densmore, Lorena Carvajal, Mario Vargas, Jarvi Vargas, and
Johnatan Vargas for their help in the field and improving this
manuscript.
LITERATURE CITED
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Published online: 5 December 2019.
APPENDIX 1. Main content of the questionnaire used on the survey in both English and native (Spanish) languages.
No. Questions Responses
1 How many crocodilian species can you identify in the area? Open
¿Cua´ ntas especies de cocodrylidos se ven en el a´rea? Abierta
2 How do you call these species? What names do they have? Open
¿C ´
omo llamas a estas especies? ¿Tienen alg ´un nombre en particular? Abierta
3 Where and when do you see white and black cachirres? Open
¿D ´
onde y cua´ ndo ves cachirres blancos y negros? Abierta
4 Where and when do you see white and black cachirres nesting? Open
¿D ´
onde y cua´ ndo ves cachirres blancos y negros anidando? Abierta
5 Where and when do you see white and black cachirres babies? Open
¿D ´
onde y cuando ves pichones de cachirres blancos y negros? Abierta
6 White and black cachirres populations in the area are increasing, decreasing, or the same
compared with 20 years ago Open
Comparado con lo visto hace 20 an˜ os, ¿la cantidad de cachirres blancos y negros ha
aumentado, disminuido o siguen igual? Abierta
7 Are white and black cachirres hunted in the area? Which ones? Reasons? Open
¿Cazan cachirres blancos y/o negros en el a´ rea? ¿Cua´les especies? ¿Cua´l es la principal raz ´
on
para cazarlos? Abierta
8 Do you think white and/or black cachirres are special creatures? Any belief around them? Open
¿Tienes alguna creencia en particular sobre los cachirres? Abierta
9 Could you explain to me what is the cachirres’ hunting history in the area? Open
¿Podrı´as contarme un poco sobre c ´
omo ha sido hist ´
oricamente la cacerı´a de cachirres en el
a´ rea? Abierta
10 What type of conflicts have you had with cachirres in the area? Open
¿Que´ tipo de conflictos o problemas ha tenido con los cachirres? Abierta
Age of respondent Open
Gender of respondent Open
Tribe of respondent Open
REDISCOVERING THE APAPORIS CAIMAN 315
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... Population ecology studies on spectacled caimans in Colombia have been highly concentrated on regions such as the Caribbean (Barahona et al. 1996, Ulloa and Cavanzo 2003, Cavanzo 2004 (Forero-Medina et al. 2006), and the Amazon (Naranjo 1996, Balaguera-Reina 2019. Most of these studies were performed across periods of time less than a year, which implies they were missing at least part of the story due to the effects of environmental annual cyclical variables (e.g., temperature, precipitation) on population parameters (e.g., number of individuals, demographic structure; Balaguera-Reina et al. 2018). ...
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Caiman crocodilus apaporiensis has been considered by several authors as an extreme of morphological variation within the Caiman crocodilus complex. Here, we evaluate its position in the Caiman crocodilus complex morphospace using morphological traits from head shape. We examined the holotype and seventeen paratypes of Caiman crocodilus apaporiensis Medem 1955 deposited at the Field Museum of Natural History. We performed multivariate morphometric analyses: principal component analysis (PCA) and discriminant function analysis (DFA), based on 21 cranial traits of of C. c. apaporiensis, C. yacare and the C. crocodilus complex (C. c. chiapasius, C. c. fuscus andC. c. crocodilus). We find a notable separation of C.c. apaporiensis from C. yacare and C. crocodilus complex in the morphospace. We suggest that geographic isolation might have driven this morphological separation from the C. crocodilus complex, but further analysis are necessary to confirm whether these differences are related with genetic differentiation within the complex. In addition, we suggest that environmental heterogeneity might drive the evolution of independent lineages within the C. crocodilus complex.
Chapter
Attempts to assess the natural affinities and evolution of living crocodilians have been difficult and largely contradictory (Kalin, 1955; Steel, 1973; Dowling and Duellman, 1974). Morphological character analysis has been misleading due to the overall conservatism of these reptiles and to the tendencies toward parallelism and convergence of traits that has occurred during their evolution (Langston, 1973). These complications, together with the lack of critical fossils, have made paleontological interpretations extremely difficult (Sill, 1968; Hecht and Malone, 1972; Langston, 1973; Buffetaut, 1979). Because of such problems and the small number of living species, morphoclines are rare, further complicating the efforts of the comparative morphologist (Hecht and Malone, 1972).