Sunday, March 22, 2009

Spaghetti eels (Moringuidae) and false moray eels (Chlopsidae)

Left: Spaghetti eel (Moringua edwardsi), Panama;
(Photo by artour_a)
Right: Bicolored false moray (Chlopsis bicolor), Italy;
(Photo by Pierpaolo Consoli)

We have looked at a wide variety of eels, from moray eels (F. Muraenidae), to snake eels (F. Ophichthidae), from conger eels (F. Congridae) and pike conger eels (F. Muraenesocidae), to the most famous eel family of all, the freshwater eels (F. Anguillidae).

In this post, I will take a look at a couple of little-known eel families, the spaghetti eels (F. Moringuidae) and false moray eels (F. Chlopsidae).

The spaghetti eels and false moray eels are widespread, and a number of species are found in shallow coastal waters of the tropics and subtropics, often close to densely populated areas. However, very little information about these 2 eel families is available online, and good luck in trying to find a photo of a live false moray eel; most of the photos I found of spaghetti eels and false moray eels were of preserved specimens on FishBase.

Apparently, the spaghetti eels are closely related to the freshwater eels, while the false moray eels are close relatives of the moray eels. Presumably, they share similar predatory habits with their more well-known kin. These 2 families are quite small, with only 14 described species of spaghetti eel, and 24 known species of false moray eel. Of course, it is likely that there are more species out there that have yet to be discovered.

Spaghetti eels are also commonly known as worm eels, but to avoid confusion with several snake eel species that go by the same name, I shall avoid calling them worm eels. They are found mostly in the Indo-Pacific, with a couple of species in the tropical western Atlantic.

Like many other eel families, spaghetti eels bury themselves in the day, emerging to feed on smaller creatures at night. Unlike other eels however, spaghetti eels burrow head-first; the pointed, heavily ossified skull and the reduced eyes are said to be adaptations for such a lifestyle. Compare this to the snake eels and the garden eels, which possess adaptations for burrowing tail-first (although some snake eel species are also adapted to some degree for head-first burrowing).

The largest species is the rusty spaghetti eel (Moringua ferruginea), which has been recorded at 1.4 metres, and the Java spaghetti eel (Moringua javanica), at 1.2 metres. Both species are widespread throughout the Indo-Pacific, from East Africa to Micronesia. Other spaghetti eel species don't even get half as long.

Rusty spaghetti eel, Easter Island;
(Photo by John E. Randall)

Some spaghetti eel species are known to enter brackish and freshwater environments; the common spaghetti eel (Moringua microchir) and the purple spaghetti eel (Moringua raitaborua) are among them.

Left: Common spaghetti eel;
(Photo by Christine Pöllabauer)
Right: Purple spaghetti eel;
(Photo by Dietmar Scholtz)

Although spaghetti eels do not appear to be heavily exploited for food, they do appear occasionally in the aquarium trade. So far, the only species which I have encountered in my online searches for spaghetti eels in aquaria are the aforementioned common spaghetti eel and purple spaghetti eel. Both species are offered as fish for the brackish water aquarium, although they are commonly sold as freshwater fish. Not much is available about their care, although like most other eels kept in aquaria, they would require plenty of hiding places to feel comfortable, a deep layer of fine substrate for them to burrow, and an escape-proof enclosure.

Left: Common spaghetti eel;
(Photo by Christine Pöllabauer)
Right: Purple spaghetti eel;
(Photo by Dietmar Scholtz)

Like the spaghetti eels, very little information on the false moray eels is available online. In fact, I think even less is known about them. Taking into account the fact that the bicolored false moray is known to live in the Mediterranean, and that this species, along with a few others, is also known from Florida and the Caribbean, it's really perplexing to find out that there's a great lack of information about false moray eels.

Head of bicolored false moray, Italy;
(Photo by Francesco Costa)

Externally, these eels do closely resemble moray eels, but based on the position of the nostrils, are thought to form a separate family. The family was once known as the Xenocongridae, and this is the family name used in many older texts. The largest species, the bicolored false moray, has been recorded at 42 centimetres; none of the other species exceed 30 centimetres in length. Like the moray eels, false moray eels are associated with reefs and rocky shores, although the bicolored false moray burrows in muddy patches of seabed, and a species from the western Atlantic, the seagrass eel (Chilorhinus suensonii), lives in sandy areas and seagrass beds. I couldn't find any information about their feeding habits, but my guess is that they are nocturnal predators on crustaceans, small fish, and cephalopods.

Within the Indo-Pacific region, the plain false moray (Kaupichthys diodontus) is widely distributed, from East Africa to Hawaii and Micronesia. However, there is some confusion as to whether it belongs to the same species as the common false moray (Kaupichthys hyoproroides), found in the western Atlantic. Some authors consider the 2 forms to be conspecific, whereas at least 1 researcher maintains that the 2 are separate species.

Plain false moray, Johnston Island;
(Photo by John E. Randall)

Sketch of plain false moray;

At this point, I've covered 7 eel families. There are actually quite a few more eel families, but I chose to focus on those families with species living in Southeast Asian waters, and which might conceivably be found living in the seas around Singapore. In fact, a great deal of eel diversity is to be found more than 200 metres beneath the surface, in the mesopelagic and bathypelagic zones.

The other eel families, such as the short-tail eels (F. Colocongridae), longneck eels (F. Derichthyidae), red eels (F. Myrocongridae), snipe eels (F. Nemichthyidae), and sawtooth eels (F. Serrivomeridae) are found exclusively in the ocean depths, whereas the mud eels (F. Heterenchelyidae), duckbill eels (F. Nettastomatidae), cutthroat eels (F. Synaphobranchidae) are predominantly deep ocean dwellers, but have representatives which inhabit shallow coastal waters. However, I did not talk about these families because the species living in shallow waters are not found in Southeast Asia.

Coming up in my final post in this series, anyone diving, fishing, or exploring the shore or river might encounter a long, eel-like creature. But is it necessarily an eel?

Part 1: Moray eels (Muraenidae)
Part 2: Snake eels (Ophichthidae)
Part 3: Conger eels (Congridae) and Pike conger eels (Muraenesocidae)
Part 4: Freshwater eels (Anguillidae)
Part 5: Spaghetti eels (Moringuidae) and false moray eels (Chlopsidae) (this post)
Part 6: Non-eels