Historical, exceptionally large skulls of saltwater crocodiles discovered at the Lee Kong Chian Natural History Museum in Singapore

Abstract

Crocodilians show a wide range of maximum Total Length (TL) and Crocodylus porosus is considered one of the largest crocodilian species with some individuals attaining more than 6 m in length. Remains of such exceptionally large crocodiles are sometimes found in different countries although details of these individuals such as TL, origin, or date of acquisition have been lost in many cases. Here we measured two exceptionally large but little known skulls found at the Lee Kong Chian Natural History Museum in Singapore and compared their morphological measurements to other large skulls reported from different countries. We found out in literature that one of the skulls, named "Edgar", had been from one of the largest crocodiles ever reported (6.7 m TL) and brought from Java to the museum in 1887. Details of the other skull, named "Giryu", still remain unknown. Based on the morphological measurements we presented here, it is likely both these crocodiles were C. porosus larger than at least 6 m TL. Given that such large individuals are hardly seen today due to previous hunting and habitat loss, these skulls have significant, biological and cultural values.

Full text

810
Fukuda et al.: Large crocodile skulls found in Singapore
Historical, exceptionally large skulls of saltwater crocodiles discovered
at the Lee Kong Chian Natural History Museum in Singapore
Yusuke Fukuda1*, Choon Beng How2, Bernard Seah3, Shufen Yang2, Kate Pocklington4 and Lim Kok Peng4
Abstract. Crocodilians show a wide range of maximum Total Length (TL) and Crocodylus porosus is considered
one of the largest crocodilian species with some individuals attaining more than 6 m in length. Remains of such
exceptionally large crocodiles are sometimes found in different countries although details of these individuals such
as TL, origin, or date of acquisition have been lost in many cases. Here we measured two exceptionally large
but little known skulls found at the Lee Kong Chian Natural History Museum in Singapore and compared their
morphological measurements to other large skulls reported from different countries. We found out in literature
that one of the skulls, named “Edgar”, had been from one of the largest crocodiles ever reported (6.7 m TL) and
brought from Java to the museum in 1887. Details of the other skull, named “Giryu”, still remain unknown. Based
on the morphological measurements we presented here, it is likely both these crocodiles were C. porosus larger
than at least 6 m TL. Given that such large individuals are hardly seen today due to previous hunting and habitat
loss, these skulls have signicant, biological and cultural values.
Key words. crocodile, Crocodylus porosus, skull, Java, Rafes
RAFFLES BULLETIN OF ZOOLOGY 66: 810–813
Date of publication: 7 December 2018
http://zoobank.org/urn:lsid:zoobank.org:pub:85153254-5711-4ADE-BAF2-5D5CFB4C61F6
© National University of Singapore
ISSN 2345-7600 (electronic) | ISSN 0217-2445 (print)
1Northern Territory Department of Environment and Natural Resources, Australia;
Email: yusuke.fukuda@nt.gov.au (*corresponding author)
2Sungei Buloh Wetland Reserve, National Parks Board, Singapore
3Bernard Photojournals, Singapore
4Lee Kong Chian Natural History Museum, National University of Singapore, Singapore
INTRODUCTION
The 24 extant species of crocodilian currently recognised
show a wide range of maximum Total Lengths (TL), including
some members exceeding 5 m in the wild. Crocodylus
porosus Schneider, 1801, commonly called the saltwater,
estuarine, or Indo-Pacic crocodile, is considered to be the
largest crocodilian species, with some individuals known to
reach more than 6 m in length (Whitaker & Whitaker, 2008;
Britton et al., 2012; Grigg & Kirshner, 2015). Biological
remains of such giants are sometimes found in the form
of preserved skulls or tanned skins in private and/or public
collections in different countries, which are often outside the
current or historical range of the species in question (Whitaker
& Whitaker, 2008). It is not unusual that such remains are
aged as these historical specimens often come from animals
that had lived before many crocodilian populations were
depleted due to uncontrolled hunting or excessive habitat
loss in the last century. It is also not unusual to lack details
on the providence and morphometric characteristics of
specimens, which have high biological and cultural values.
Here we report on two large, little known skulls of crocodiles
discovered in the collection at Lee Kong Chian Natural
History Museum (LKCNHM) in Singapore, and provide
detailed morphological measurements and estimates of TL
of the individuals from which they were derived.
MATERIAL & METHODS
Cranium (upper jaw) and mandible (lower jaw) named
“Edgar” and another cranium named “Giryu” (義龍) are
included in the Zoological Reference Collection (accession
numbers ZRC 2.7300 for Edgar and ZRC 2.7301 for Giryu,
Fig. 1) at the LKCNHM (formerly Raffles Museum of
Biodiversity Research), National University of Singapore,
Singapore. No details such as the species, origin, size and
age of these specimens were available until this study was
conducted.
We measured the two skulls at LKCNHM on 17 April
2018, using two 100 cm rulers and a 500 cm tape measure,
both made of stainless steel. We followed the standardised
methods for measuring crocodilian skulls, including those
used by Britton et al. (2012). First we measured the Dorsal
Cranial Length (DCL) A (Fig. 2) on both craniums, which
is the length between the tip of the snout and the rear of the
cranial platform (parietal in the occipital part) along the mid-
line of a skull. DCL A is the head length measurement most
commonly referred to for a crocodilian skull or head. We
also measured DCL B which is DCL but at a horizontal level
(Fig. 2). Because DCL B ignores the slope on the cranium, it
is shorter than DCL A and is used only in a supplementary
manner for estimating the size of an animal. We measured
DCL B of Edgar, but not Giryu, as the absence of the lower
jaw in the latter would affect the DCL B angle. We then
measured Maximum Cranial Width (MCW), which is the
Taxonomy & Systematics

811
RAFFLES BULLETIN OF ZOOLOGY 2018
Table 1. Measurements of the two skulls (Edgar and Giryu) found at LKCNHM, Singapore. See text for the abbreviations. The measurements
for other crocodiles in a similar size (Lolong, Corroboree, and Old Charlie) were included for comparative purposes.
Skull DCL A (mm) DCL B (mm) MHW (mm) MCW (mm) IOW (mm) TL (cm)
Edgar 701 682 520 240 80 670&^
Giryu 706 n/a n/a 205 67 n/a
Lolong* 700 694 450 228 84 617.0
Corroboree¶728 n/a 458 230 71 670^
Old Charlie† 666 n/a 480 235 75 615.0
&From Hanitsch (1908). *From Britton et al. (2012). ¶ From Manolis (2006). This skull is also reported by Whitaker and Whitaker (2008),
but measurements in Manolis (2006) are considered more accurate since the skull was bleached and damaged after 2006. †From Webb
& Messel (1978). ^Not measured but estimated.
Fig. 1. Exceptionally large skulls of Crocodylus porosus Schneider,
1801 discovered at the Lee Kong Chian Natural History Museum
(LKCNHM). Edgar on left and Giryu on right.
Fig. 2. Measurement of Dorsal Cranial Length (DCL) A and B of
Edgar, Crocodylus porosus Schneider, 1801.
maximum width of the cranial plate between squamosals,
and Inter-Orbital Width (IOW), which is the minimum
width between orbits (eyes) (Fig. 3). We also measured the
Maximum Head Width (MHW), which is the width at the
widest part (usually mandible) of a head (Fig. 3) for Edgar,
but not Giryu as it did not have the lower jaw.
RESULTS
Although Edgar (with lower jaw) was slightly shorter (0.7%)
than Giryu (upper jaw only), it was considerably wider than
the latter (17.1%; Table 1). Edgar had two teeth left (one
on the right side of the upper jaw and the other on the left
side of the lower jaw) while Giryu had none.
During the measurement of Edgar, we found handwriting that
read “5/4/1887” on the inner side of the left, retroarticular
process of the articular (Fig. 4). We later discovered that
Hanitsch (1908) had reported that a large skull of C. porosus
was presented to the museum by Mr. G. Edgar in 1887. He
described that the skull length, which is considered equivalent
to DCL A, was 27.5 inches (699 mm). He also noted that
the skull “must have belonged to a monster quite 22 feet
in length” (equivalent to 670.5 cm) and “it probably came
from Java”. Although details of the smaller skull remained
unknown, the morphological characteristics such as the two
elevated ridges running between the openings of the eyes
and nostril (Fig. 1).
DISCUSSION
Within large crocodiles, the head could cease increasing
in its length although width may continue to grow, thus a
combination of morphological measurements for the head
width may be a more accurate index for predicting TL
(Webb & Messel, 1978). For example, a large skull located
in Darwin of the Northern Territory, Australia known as
Old Charlie is shorter than that of Lolong, another large C.
porosus captured in Philippines in 2011, but this does not
mean that Old Charlie was smaller than Lolong. In fact, Old
Charlie’s skull was wider than Lolong and both crocodiles
were in similar TL (Table 1). Likewise, Edgar is shorter
but considerably wider than Corroboree, the largest skull in
Australia, and both crocodiles may have been in a similar
size (6.7 m TL). Corroboree was originally caught at the
Point Sturt in the Northern Territory (NT) in the 1970s and
now on display at the Corroboree Tavern in the NT. If these
crocodiles were in a similar size, Corroboree’s TL reported

812
Fukuda et al.: Large crocodile skulls found in Singapore
by the owner who observed the animal when captured is
likely to be a reasonable estimate as it is consistent with
Hanitsch (1908) reporting that Edgar came from a 22 ft
(approximately 6.7 m) crocodile. Edgar is actually the widest
skull ever recorded (Whitaker & Whitaker, 2008; Britton et
al., 2012). In contrast, Giryu had the narrowest skull of the
four, but with a slightly longer head than Lolong, which
indicates that the crocodile might have been smaller than
Lolong (6.17 m TL).
To the best of our knowledge and available literature (e.g.,
Webb & Messel, 1978; Kar, 2006; Manolis, 2006; Whitaker
& Whitaker, 2008; Britton et al., 2012; Grigg & Kirshner,
2015), there are only 12 C. porosus skulls known to be
longer than 700 mm DCL, two of which are Edgar and Giryu.
The largest skull, reported to be 760 mm, is at the Paris
Museum, and was collected from Cambodia in the 1800s,
but TL is unknown (Whitaker & Whitaker, 2008; Grigg &
Kirshner, 2015). HL or DCL alone has been widely used
to estimate TL of crocodilians although many datasets are
biased towards smaller individuals and there is known to be
a signicant variation in their HL:TL ratios (Webb & Messel,
1978). Fukuda et al. (2013) calculated HL : TL ratios for C.
porosus from 2,755 individuals ranging from 38 to 503 cm
long and showed that 1 : 7 ratio can be used to predict TL
with reasonable accuracy. Moreover, a few reliable records
suggested that the ratio increasingly becomes higher as a
crocodile grows exceptionally large (e.g., 1 : 8.81 for Lolong
with 6.17 m TL). Accounting these observations, all these 12
skulls are most likely from crocodiles longer than 600 cm
TL and some may have been close to 700 cm. Given that
C. porosus with such large TL are rarely seen today because
of previous hunting and habitat loss, the biological and
cultural values of these historical skulls cannot be over-stated.
LKCNHM is considering incorporating both of the skulls
in its educational displays within the Biodiversity Gallery.
In Singapore, historical data for some individuals measuring
609 cm (recorded as 20 feet in length) have been found
Fig. 3. Measurement of head length (DCL A and B, see Fig. 2),
Inter-Orbital Width (IOW), Maximum Cranial Width (MCW) and
Maximum Head Width (MHW) of Edgar, Crocodylus porosus
Schneider, 1801.
Fig. 4. Handwritten date on the mandible of Edgar, Crocodylus
porosus Schneider, 1801. It is unknown whether this date refers
to a day when the skull was obtained in the eld or presented to
the museum by Mr. G. Edgar.
recorded in digitised newspapers. These measurements were
taken from captured or shot individuals at 20 ft length in
1863 (The Straits Times, 1863) and 1904 (The Straits Times,
1904). Other measurements exceeding these, such as 762
cm, recorded as 25 ft length (The Straits Times, 1960) and
914 cm recorded as 30 ft length (The Straits Times, 1878)
were taken from sightings only and are most likely to be
utterly overestimated or exaggerated.
ACKNOWLEDGEMENTS
We thank Tony Pine who helped us measure the skulls
and Shimpei Ochi at Herpetological Society of Japan who
encouraged us to publish this article. We are thankful to
Charlie Manolis, Rom Whitaker and anonymous reviewers
for their constructive inputs. Charlie Manolis re-measured
the skull “Corroboree” for this study. Funding for Y. Fukuda
was provided by National Geographic Society – Asia (grant
number 51-16).
LITERATURE CITED
Britton ARC, Whitaker R & Whitaker N (2012) Here be a dragon:
Exceptional size in a saltwater crocodile (Crocodylus porosus)
from the Philippines. Herpetological Review, 43: 541–546.
Fukuda Y, Saalfeld K, Lindner G & Nichols T (2013) Estimation
of total length from head length of saltwater crocodiles
(Crocodylus porosus) in the Northern Territory, Australia.
Journal of Herpetology, 47: 34–40.
Grigg G & Kirshner D (2015) Biology and Evolution of
Crocodylians. Cornell University Press, New York, 649 pp.
Hanitsch R (1908) Guide to the Zoological Collections of the Rafes
Museum, Singapore. Straits Times Press, Singapore, 112 pp.
Kar S (2006) Record of a large saltwater crocodile from Orissa,
India. Crocodile Specialist Group Newsletter, 25(3): 27.
Manolis C (2006) Record of a large saltwater crocodile from
the Northern Territory, Australia. Crocodile Specialist Group
Newsletter, 25(3): 27–28.
Schneider JG (1801) Historiae Amphibiorum naturalis et
literariae. Fasciculus secundus continens Crocodilos,
Scincos, Chamaesauras, Boas. Pseudoboas, Elapes, Angues.
Amphisbaenas et Caecilias. Frommanni, Jena, Germany, 374 pp.
The Straits Times (1863) Wednesday, 10th June. The Straits
Times 13 June 1863. http://eresources.nlb.gov.sg/newspapers/

813
RAFFLES BULLETIN OF ZOOLOGY 2018
Digitised/Article/straitstimes18630613-1.2.9.2.aspx. (Accessed
22 November 2015).
The Straits Times (1878) Wednesday, 3rd July. The Straits Times
6 July 1878. http://eresources.nlb.gov.sg/newspapers/Digitised/
Article/straitstimes18780706-1.2.16.2.aspx. (Accessed 22
November 2015).
The Straits Times (1904) Catching a crocodile. The Straits
Times 31 May 1904. http://eresources.nlb.gov.sg/newspapers/
Digitised/Article/straitstimes19040531-1.2.25.aspx (Accessed
12 September 2015).
The Straits Times (1960) Croc scares shermen. The Straits Times
18 March 1960. http://eresources.nlb.gov.sg/newspapers/
Digitised/Article/straitstimes19600318-1.2.154.aspx (Accessed
12 September 2015).
Webb GJW & Messel H (1978) Morphometric analysis of
Crocodylus porosus from the north coast of Arnhem Land,
northern Australia. Australian Journal of Zoology, 26: 1–27.
Whitaker R & Whitaker N (2008) Who’s got the biggest? Crocodile
Specialist Group Newsletter, 27(4): 26–30.