User:Chinasaur/Remora

A remora, or suckerfish, is a fish of the order Perciformes, family Echeneidae. These fish are best known for the unusual sucking disc on their heads, which they use to "hitchhike" by attaching themselves to larger ocean inhabitants, such as fish, turtles, sharks, whales, or even boats. The evolution of the sucking disc is only beginning to be understood, but the hitchhiking behavior has been known at least since ancient times, when it was noted in the histories of Pliny. A number of early societies capitalized on the remora's unique suction ability, using the fish as a kind of living fishhook to catch other animals, especially turtles.

Taxonomy
Family Echeneidae (sometimes called "Echeneididae" in older texts) comprises eight species, which are traditionally grouped into four genera:
 * Genus Echeneis
 * Live sharksucker, Echeneis naucrates Linnaeus, 1758.
 * Whitefin sharksucker, Echeneis neucratoides Zuiew, 1786.
 * Genus Phtheirichthys
 * Slender suckerfish, Phtheirichthys lineatus (Menzies, 1791).
 * Genus Remora
 * Whalesucker, Remora australis (Bennett, 1840).
 * Spearfish remora, Remora brachyptera (Lowe, 1839).
 * Marlin sucker, Remora osteochir (Cuvier, 1829).
 * Common remora, Remora remora (Linnaeus, 1758).
 * Genus Remorina
 * White suckerfish, Remorina albescens (Temminck & Schlegel, 1850).

Traditionally, these genera are further grouped into two subfamilies: Echeneiinae, comprising Echeneis and Phtheirichthys, and Remorinae, comprising Remora and Remorina. The Echeneiinae are distinct from the Remorinae in having long, snake-like bodies and a pointed lower jaw that jutts out beyond the upper. The Remorinae have shorter, stouter bodies and heads, and their sucking disc is large and broad.

However, recent, more detailed analyses dispute this break down. In an extensive 2002 study, Bruce O'Toole used 138 distinct morphological characteristics to categorize the echeneids and related species. His analysis led to a well-supported phylogenetic hypothesis that renders both subfamily Echeneiinae and genus Remora paraphyletic. Thus, O'Toole recommends subsuming Remorina into Remora, which renders Remora monophyletic, also making Remorinae superfluous. He further recommends eliminating the paraphyletic Echeneiinae group, thus wholly eliminating the subfamily taxonomy.

Finally, the echeneids also belong to superfamily Echeneoidea, along with two other families, Rachycentridae and Coryphaenidae. These relationships are discussed further in the evolution section.

Morphology
For an extensive morphological break down of the echeneids and related species, see O'Toole (2002). Briefly...

Hitchhiking behavior

 * How accomplished, backwards versus forwards for attach/release
 * Purpose, nature of relationship, scavenging, fecal
 * Within gills?
 * Different levels of host specificity
 * Different levels of freeswimming

Evolution
The echeneids are placed in superfamily Echeneoidea, reflecting the belief that Echeneidae shares an immediate common ancestor with the families Rachycentridae and Coryphaenidae, although Rachycentridae and Coryphaenidae do not have the sucking disc adaptation.

Based on O'Toole's comparative morphological analysis, the most probable phylogeny is...

The different styles of hitchhiking behavior can be considered within the framework of O'Toole's phylogeny...
 * Schooling behavior, extraspecial schooling

There is one known fossil form that appears to be intermediate in the evolution of Echeneidae from Rachycentridae. Opisthomyzon glaronensis is a fossil from Upper Eocene deposits in Glarus, Switzerland. Although Opisthomyzon does sport a sucking disc, it is quite different from those of the echeneids, being shorter, narrower, and pointed towards the rear. Among the echeneids, Phtheirichthys is thought to be closest to Opisthomyzon.

Etymology and mythology of the "ship stopper"
In ancient times, the remora was believed to stop a ship from sailing. In Latin remora means "delay", while Echeneis comes from Greek echein ("to hold") and naus ("a ship"). Particularly notable is the account of Pliny the Younger, in which the remora is blamed for the defeat of Mark Antony at the Battle of Actium and (indirectly) for the death of Caligula.

Accounts of remora holding or retarding ships are widespread in literature up to as late as the 18th century. Notable examples include the following lines from Rabelais's Pantagruel:
 * The sucking-fish, with secret chains,
 * Clung to the keel, the swiftest ship detains.

In 20th century texts, the ability of a single remora to slow a ship is discounted, yet the possibility of a large school of remoras slowing a ship is quite seriously entertained.

The "reversus"
Because of the shape of the jaws, appearance of the sucker, and coloration, some remoras appear to be upside-down when they are in fact swimming normally. This probably led to the older common name reversus, although this might also derive from the fact that the remora frequently attaches itself to the tops of manta rays or other fish, so that the remora in fact is upside-down while attached.

The "fishing fish"
Remoras have been used for catching turtles in a remarkable way: a cord is fastened to the remora's tail, and when a turtle is sighted the fish is released from the boat; it usually heads directly for the turtle and fastens itself to the turtle's shell, and then both remora and turtle can be hauled in. Smaller turtles can be pulled completely into the boat by this method, while larger ones are hauled within harpooning range. Sometimes, the hunter will jump from the boat with rope in hand, using it to follow the turtle until it can be captured or killed at close quarters.

This practice has been reported throughout the Indian Ocean, especially from eastern Africa near Zanzibar and Mozambique, and from northern Australia near Cape York and Torres Strait.

Similar reports have also come from Japan and from the Americas. In fact, some of the first records of the "fishing fish" in the Western literature come from the original accounts of the second voyage of Christopher Columbus. However, Leo Wiener considers the Columbus accounts to be apocryphal: what was taken for accounts of the Americas may have in fact been notes that Columbus took from accounts of the East Indies, his desired destination.

Modern references
The remora has frequently been referenced in modern culture, for example:
 * In the Wing Commander space combat series of computer games, there is a ship called the remora.
 * Remoraid is a Pokémon that looks like a remora.
 * In A Series of Unfortunate Events by Lemony Snicket, there is a teacher named Mr. Remora.
 * In the 1996 action film Executive Decision with Kurt Russell, terrorists hijack a commercial plane going towards the US carrying a bomb loaded with DZ-5, planning to kill 40 million citizens. Meanwhile, at the Pentagon, a plan is worked out that will involve a mid-air transfer on a commando team onto the hijacked airliner using an experimental "Remora" aircraft