Article

Lizards

From Munshipedia, the MBRAS digital historical encyclopedia

Lizards

Lizards constitute a diverse and widespread group of reptiles across the Malay Peninsula and Borneo, encompassing arboreal, terrestrial, and semi-aquatic forms that have attracted sustained scientific attention since the earliest decades of colonial natural history in the region. The literature preserved in the Society’s journals documents species ranging from the small arboreal Aphaniotis fusca to the gliding Draco lizards, from introduced Australian skinks to newly described ground-geckos, reflecting both the taxonomic richness of the fauna and the evolving methodological approaches of the naturalists who studied it. The records span nearly five decades, from brief field observations in the 1880s to detailed morphological monographs in the 1920s, and collectively reveal a discipline in transition from descriptive natural history towards systematic, measurement-based taxonomy.

Taxonomic Documentation and Morphological Description

The most substantial contribution to lizard taxonomy in the archival record is G. Hope Sworder’s 1929 monograph on Aphaniotis fusca (Peters), a small arboreal species based on 17 specimens from the Malay Peninsula and the Natuna Islands [1]. Sworder’s study was prompted by apparent contradictions between his own observations and all previous descriptions of the species, which he resolved by attributing the discrepancies to sex-based differences and to the loss of the gular sac in preserved female specimens after prolonged immersion in spirit [1, p. 328]. He documented the presence of a well-developed gular sac in males and a smaller one in females, necessitating a correction to Boulenger’s 1912 generic description, which had stated “no gular pouch” [1, p. 328]. Sexual dimorphism was pronounced: males possessed irides of bright blue with a cobalt-blue interior of the mouth, while females had gold-brown irides and two dark bands between the eyes, making the sexes distinguishable “infallibly even at some distance” [1, p. 329].

Sworder’s morphological analysis extended to head-scale variation across localities, which he identified as the most promising character for future subspecific differentiation. The Gemas series showed a normal arrangement of three scales above the rostral, while specimens from Sedili (Johore) and P. Tioman each possessed a single large scale, and a specimen from Parit (Perak) displayed a rosette-shaped group of five scales [1, pp. 330–331]. The Parit specimen was further distinguished by more strongly keeled scales throughout, a nuchal crest on a slight nuchal fold, and a greenish colour in spirit, setting it apart from all other localities [1, p. 331]. Sworder explicitly invited other workers with access to additional material to contribute detailed descriptions and drawings, framing the question of subspecific recognition as an open one [1].

In 1925, Malcolm A. Smith described a new species of ground-gecko, Gymnodactylus sworderi, from a single male specimen collected by Hope Sworder approximately nine miles north of Kota Tinggi, Johore, in September 1924 [2]. The species was characterised by an oval oblique ear opening, a large quadrangular rostral, 14 upper and 10 lower labials, a large subtriangular mental with a pair of chin-shields, granular dorsal scales with larger rounded tubercles, two diverging rows of three preanal pores, and 10–11 pitted femoral scales; total length was 135 mm [2]. Smith noted the species was most closely related to G. peguensis Boulenger from lower Burma and Siam, differing in preanal pore arrangement, supralabial count, and colouration, and the type specimen was deposited in the British Museum of Natural History [2].

E. Bartlett’s 1895 note on a new species of “Philentoma” represents an earlier, briefer contribution to the taxonomic literature, though the archival record provides only the title and page reference without detailed content [3].

Natural History and Behavioural Observations

The earliest lizard records in the Society’s literature take the form of short natural history notes rather than formal taxonomic treatments. N. B. Dennys’s 1882 account of Draco volens in Singapore described the species as abundant and capable of a considerable length of flight, with eggs “about the size of peas” [4, p. 162]. Dennys added a general observation that no species of lizard is in any sense poisonous and that very few possess teeth developed enough to inflict a wound, and noted that spiders are great enemies of lizards, typically catching them asleep and weaving a web around the mouth before biting the lip [4, p. 163]. The note closed with an invitation for readers to keep the animal in confinement and furnish further information [4].

Sworder’s 1929 monograph provided more detailed behavioural data for Aphaniotis fusca, recording that the species is active and arboreal, often found on tree trunks 6 to 20 feet above the ground, and capable of springing four to five feet sideways between trunks in a manner he likened to Draco, with which it is readily confused at a distance [1]. Reproductive data showed that nearly all gravid females in the Gemas series, plus the P. Tioman specimen, contained two fully developed oval eggs measuring approximately 18 mm by 7 mm [1, p. 329].

H. N. Ridley’s 1905 note, titled “Nesting of Draco fimbriatus,” presents a textual anomaly: the body of the note refers throughout to “the bird” and describes an individual roosting in a hole in a dead bough in the Gardens, with no eggs or young found despite it being the breeding season [5, p. 227]. This inconsistency may indicate a misattribution of the title to the fragment, or that the note was part of a longer discussion in which the subject shifted [5].

Introduced and Range-Extension Records

The archival record also documents cases of lizards occurring outside their native range, whether through human-mediated introduction or range extension. F. N. Chasen’s 1925 note on the Australian skink Egernia depressa (Gunth.) in Singapore Island reported that a specimen was captured near the Tanjong Pagar docks, and that four other Egernia specimens in the Raffles Museum were presumably also taken on the island [6, pp. 100–101]. The species was described as roughly the size of the common garden skink Mabuia multifasciata but distinguished by its stumpy tail and rows of backwardly directed spines [6]. Chasen attributed the introduction to timber-carrying boats from south-western Australian ports, and noted the species’ confinement to the dock area as evidence it had not yet spread beyond its point of arrival [6, p. 101]. He placed this within a broader discussion of artificially introduced reptile and amphibian species on the island, including the bull-frog Kaloula pulchra and the tokay gecko Gekko verticillatus, whose confinement to urban areas he cited as evidence of artificial introduction [6, p. 100].

H. C. Robinson’s 1905 note recorded the discovery of Draco maximus, a flying lizard from Borneo, in Selangor, where it was captured in deep jungle about nine miles from Kuala Lumpur by the Dyak collector attached to the Selangor Museum [7, pp. 223–225]. Robinson noted this represented a species previously unrecorded from the Malay Peninsula, and provided brief measurements and colouration data [7].

Research and Documentation

The Society’s literature on lizards reveals a clear trajectory from brief, impressionistic natural history notes in the 1880s and 1900s towards the measurement-based, camera-lucida-illustrated monographs of the 1920s. Dennys’s 1882 account and Ridley’s 1905 fragment represent the earlier mode: short, observational, and often lacking in precise morphological data, with the former explicitly inviting reader participation in the form of keeping specimens in confinement [4]. The middle period, exemplified by Robinson’s 1905 range-extension note and Bartlett’s 1895 species description, occupies an intermediate position, providing measurements and locality data but without the systematic comparative framework that characterises the later work [7], [3].

Sworder’s 1929 monograph marks a decisive methodological shift. His use of 16 fully adult specimens measured and examined both in life and after preservation, his camera-lucida illustration at magnified scale, and his explicit framing of head-scale variation as a basis for future subspecific work represent an early example of systematic herpetological documentation in the Malay Peninsula [1]. The paper’s reliance on both personal field material (the Gemas series, collected July 1928) and museum loans (from the Raffles Museum, Singapore) illustrates the collaborative infrastructure that underpinned the discipline at this stage [1]. Smith’s 1925 description of Gymnodactylus sworderi, though based on a single specimen, follows the same taxonomic conventions of precise scale counts and comparative diagnosis [2].

The records also reveal the practical constraints of the period: the loss of diagnostic features in preserved specimens (the gular sac in Aphaniotis females), the difficulty of obtaining embryos or newly hatched specimens (Dennys’s explicit failure with Draco volens), and the reliance on single specimens for range-extension records (Robinson’s Draco maximus, Smith’s Gymnodactylus sworderi) [1], [4], [7], [2]. These limitations shaped the cautious, provisional tone of much of the literature, with authors frequently inviting further collection and description rather than drawing definitive conclusions.

MBRAS Sources

References

  1. G.H. Sworder (1929). Notes on the Aphaniotis fusca (Peters JMBRAS 7(2): 327–335.
  2. M.A. Smith (1925). A new ground-gecko (Gymnodactylus) from the Malay Peninsula. Records of the Raffles Museum, No. 7 JMBRAS 3(1): 87. Read on JSTOR
  3. E. Bartlett (1895). On a new species of “Philentoma” JSBRAS 28: 96–97.
  4. N.B. Dennys (1882). Flying lizard JSBRAS 9: 162–163.
  5. H.N. Ridley (1905). Nesting of Draco fimbriatus JSBRAS 44: 227.
  6. F.N. Chasen (1925). On the introduction of the Australian skink into Singapore Island. Records of the Raffles Museum, No. 12 JMBRAS 3(1): 99–101. Read on JSTOR
  7. H.C. Robinson (1905). Note on the occurrence in Selangor of three vertebrates new to the Malay Peninsula JSBRAS 44: 223–225. Read on JSTOR