''Cheilodipterus novemstriatus'', the Indian Ocean twospot cardinalfish, is a species of ray-finned fish from the Indian Ocean, which is a member of the family

Apogonidae Cardinalfishes are a family, Apogonidae, of ray-finned fishes found in the Atlantic, Indian, and Pacific Oceans; they are chiefly marine, but some species are found in brackish water and a few (notably '' Glossamia'') are found in fresh water. ...

. It has colonised the eastern Mediterranean Sea by way of the Suez Canal since 2011.

Description

''Cheilodipterus novemstriatus'' has a slender body with a short snout, a terminal mouth which has canine-like teeth in both jaws, although no teeth occur at the

symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...

of the lower jaw, and a large eye. Of the two dorsal fins, the origin of the first is slightly behind the origin of the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

is in line with the second dorsal fin and the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

is forked. The body is an overall silver-grey in colour with five contrasting, longitudinal black stripes with the upper running near the base of the dorsal fin. The middle or third stripe starts at the snout running across the eye to the caudal peduncle, while the lower stripe runs along ventral surface in an arc, which terminates in front of the base of the pectoral fin, the portion of this stripe often becomes indistinct towards the base of the anal fin. The caudal peduncle has a large, oval, black spot which is surrounded by yellow background on the caudal peduncle and a second black spot is located on the dorsal surface of caudal peduncle. It is a small species, reaching a maximum length of , but more commonly measures in length.Atlas of Exotic Fishes in the Mediterranean Sea (''Cheilodipterus novemstriatus''). 2nd Edition. 2021. 366p. CIESM Publishers, Paris, Monaco.https://ciesm.org/atlas/fishes_2nd_edition/Cheilodipterus_novemstriatus.pdf

Distribution

''C. novemstriatus'' is native to the western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

from the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

to the

Persian Gulf The Persian Gulf, sometimes called the Arabian Gulf, is a Mediterranean seas, mediterranean sea in West Asia. The body of water is an extension of the Arabian Sea and the larger Indian Ocean located between Iran and the Arabian Peninsula.Un ...

. In 2011, it was recorded in the Mediterranean Sea off

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

, then in Lebanon in 2012, southeastern Turkey in 2014 and in Cyprus in 2015. It is now established in the

Levantine Sea The Levantine Sea () is the easternmost part of the Mediterranean Sea. Geography The Levantine Sea is bordered by Turkey in the north and north-east corner, Syria, Lebanon, Israel, and Palestine in the east, Egypt in the south, and the Aegean ...

, most likely introduced from the Red Sea via the

Suez Canal The Suez Canal (; , ') is an artificial sea-level waterway in Egypt, Indo-Mediterranean, connecting the Mediterranean Sea to the Red Sea through the Isthmus of Suez and dividing Africa and Asia (and by extension, the Sinai Peninsula from the rest ...

Biology

''C. novemstriatus'' is common in shallow, sheltered waters and is found at depths of over rocky reefs or coral, which have holes and ledges. It will shelter among the spines of

sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...

s of the genus '' Diadema'' in groups of as many as 30 individuals, although this depends on the relative sizes of the urchin to those of the fishes. It has also been recorded from a shipwreck at a depth of in the Mediterranean, where it was sympatric with the indigenous Mediterranean cardinalfish '' Apogon imberbis''; it has also been recorded on hard substrates covered with calcareous algae, near rocky crevices and overhangs. It has been recorded sheltering alongside juveniles of the native

wrasse The wrasses are a family, Labridae, of marine ray-finned fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into nine subgroups or tribes. They are typically small, ...

'' Coris julis''. ''C. novemstriatus'' is nocturnal and emerges from its daytime shelters to feed in more open areas, and its nocturnal habits may have facilitated its successful invasion of the eastern Mediterranean, as few indigenous nocturnal competitors exist. Its main food is

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

, and in the Red Sea, it is frequently encountered at night along sandy shores at depths of 0.5–1.5 m. It is a social species and gathers in large groups, especially in its daytime shelters and even in the newly established Mediterranean populations, large schools have been encountered. Like other species of cardinalfish, ''C. novemstriatus'' shows pairing behaviour and courtship and the male broods the eggs in his mouth.

References

{{Taxonbar, from=Q2171432 novemstriatus Taxa named by Eduard Rüppell Fish described in 1838