Enigmas: keeping their secrets

By Lee Kong Chian Natural History Museum

Lee Kong Chian Natural History Museum

From
the Latin and Greek meaning to speak allusively, and therefore to obscure
meaning. These creatures have many natural history secrets and those they
have grudgingly yielded are astounding

Hermatobates cf. marchei (2010-04-15) by Tran Anh DucLee Kong Chian Natural History Museum

Hermatobates singaporensis Cheng, 1976

The genus Hermatobates contains 12 species and is among the most elusive and rarely-encountered group of true bugs. For example, at the time when Hermatobates singaporensis was first described from Singapore in 1976, only three specimens were known. Members of the genus are found exclusively in marine habitats, usually on rocky shores and intertidal corals. They are sometimes known as “coral treaders”.

Hermatobates cf. marchei (2010-04-15) by Tran Anh DucLee Kong Chian Natural History Museum

All species of Hermatobates are unable to fly, being completely wingless throughout their lives. At high tide, they hide in air pockets trapped in crevices or holes under boulders. Scientists also think that a layer of fine water-repelling hairs on their body surface may also help to trap air when they are submerged underwater.

Hermatobates cf. marchei (2010-04-15) by Tran Anh DucLee Kong Chian Natural History Museum

At low tide they emerge, treading on the water surface to feed on small invertebrates. Apart from this scant information, their natural history remains a mystery. Hermatobates singaporensis is probably one of the rarest species in the genus and is found only in ASEAN and is so far only known from Singapore.

Banded Goby (Hemigobius mingi) (2018-07-18) by Tran Dac DinhLee Kong Chian Natural History Museum

Banded Goby
Hemigobius mingi (Herre, 1936)

Most commonly found in mangroves, this fish is often found hovering almost upright above the bottom in small groups. In doing so, they appear very prominent against the bottom because of the silvery lines on their dark grey bodies. This display is unusual because many closely-related species are solitary in habit and remain close to the bottom, or otherwise attempt to appear less prominent. In most natural settings, to be prominent is to become someone else’s dinner. Scientists are still puzzled by this enigmatic behaviour. This species is restricted to ASEAN and is found in Brunei, Indonesia, Malaysia, Singapore and Thailand.

Bornean Flat-headed Frog (Barbourula kalimantanensis) (2007-08-13) by Heok Hui TanLee Kong Chian Natural History Museum

Bornean Flat-headed Frog
Barbourula kalimantanensis Iskandar, 1978

When this frog was first discovered in the Kapuas River (in Kalimantan, Borneo) in 1976, it was the first known species of the family from Borneo. In 2007, scientists were able to study this species in further detail. This led to the remarkable discovery that this frog has no lungs! Complete lunglessness is known only in amphibians and the Bornean Flat-headed Frog is the only known frog without a pair.

Bornean Flat-headed Frog (Barbourula kalimantanensis) (2007-08-13) by Heok Hui TanLee Kong Chian Natural History Museum

This species ‘breathes’ by drawing in oxygen directly through its skin from the cold, oxygen-rich streams in which it lives. Little else is known about its natural history. Furthermore, this species is only found in a small area in Kalimantan and is threatened by human activities that pollute the streams it lives in. This species is only known from ASEAN from Indonesia.

Enigmatic Saddle Oyster (Enigmonia aenigmatica) (2004-01-01) by Ria TanLee Kong Chian Natural History Museum

Enigmatic Saddle Oyster
Enigmonia aenigmatica (Holten, 1802)

A species overflowing with the enigmatic is the Enigmatic Saddle Oyster. Its common name and its scientific name (twice!) indicate that it is an enigma. Although recognised as a distinct species in 1802, it was only when animals were first observed alive that the truly remarkable nature of this species became apparent.

Enigmatic Saddle Oyster (Enigmonia aenigmatica) (2004-01-01) by Ria TanLee Kong Chian Natural History Museum

The two largest groups of molluscs are the snails (“gastropods”) and clams (“bivalves”). In general, snails crawl around and clams do not. The Enigmatic Saddle Oyster is clam-like but crawls around snail-like!

Enigmatic Saddle Oyster (Enigmonia aenigmatica) (2005-08-09) by Ria TanLee Kong Chian Natural History Museum

Charles M. Young made observations on living animals sent to him from Singapore in 1957. On placing the animals on glass slides, he was able to observe their movements from the other side of the glass.

Enigmatic Saddle Oyster (Enigmonia aenigmatica) (2010-04-25) by Siong Kiat TanLee Kong Chian Natural History Museum

This species can have both light- and dark-coloured forms, and the shell often grows to conform to the surface it is attached to. This has led to scientists naming some of these forms as distinct species. Outside of ASEAN, this species is found in Australia and China. Within ASEAN, it is found in Malaysia, the Philippines and Singapore.

Greenbottle Fly (Isomyia nebulosa) (2018-06-28) by Yuchen AngLee Kong Chian Natural History Museum

Greenbottle Fly
Isomyia nebulosa (Townsend, 1917)

The Greenbottle Fly comes from a group of flies that are known as “carrion flies” due to their affinity for decomposing flesh. Greenbottle Fly, however, comes from a ‘vegan’ subgroup that avoids meat and has only been recorded feeding on flower nectar. Beyond this, the natural history of the Greenbottle Fly is rather nebulous (like its scientific name!).

The Greenbottle Fly was first discovered in Peninsular Malaysia when a dead individual was found parasitised by a cordyceps fungus (which is well-known as a Chinese ‘materia medica’).

Outside of ASEAN, this species is known from India. Within ASEAN, it is found in Laos, Peninsular Malaysia and Myanmar.

Enigmatic Saddle Oyster (Enigmonia aenigmatica) (2010-04-25) by Siong Kiat TanLee Kong Chian Natural History Museum

This are some of the mysteries that have been cracked by researchers—and many more remain. Just imagine all the others which we do not even know about!

Credits: Story

Text:

Banded Goby
Zeehan Jaafar
(National University of Singapore, Singapore)

Bornean Flat-headed Frog
Chen Ming Li
(National University of Singapore, Singapore)

Enigmatic Saddle Oyster
Siong Kiat Tan
(National University of Singapore, Singapore)

Greenbottle Fly
Yuchen Ang
(National University of Singapore, Singapore)

Hermatobates cf. marchei
Wei Song Hwang
(National University of Singapore, Singapore)
Tran Anh Duc
(Hanoi University of Science, Vietnam)


Images:

Banded Goby
Tran Dac Dinh
(Can Tho University, Vietnam)

Bornean Flat-headed Frog
Heok Hui Tan
(National University of Singapore, Singapore)

Enigmatic Saddle Oyster
Ria Tan
(Wild Singapore, Singapore)

Greenbottle Fly
Yuchen Ang
(National University of Singapore, Singapore)

Hermatobates cf. marchei
Tran Anh Duc
(Hanoi University of Science, Vietnam)

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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