''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. A h ...

. 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 (, pl. 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 ...

of the lower jaw, and a large eye. Of the two

dorsal fins A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

, 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 surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

. The

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is in line with the second dorsal fin and the

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

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.

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 ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

from the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

to the

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Persis, Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a Mediterranean sea (oceanography), me ...

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

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

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

Levantine Sea The Levantine Sea (Arabic: بحر الشام, tr, Levanten Denizi, el, Θάλασσα του Λεβάντε) is the easternmost part of the Mediterranean Sea. Geography The Levantine Sea is bordered by Turkey in the north and north-east co ...

, most likely introduced from the Red Sea via the

Suez Canal The Suez Canal ( arz, قَنَاةُ ٱلسُّوَيْسِ, ') is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea to the Red Sea through the Isthmus of Suez and dividing Africa and Asia. The long canal is a popular ...

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 () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

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 fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into 9 subgroups or tribes. They are typically small, most of them le ...

Coris julis The Mediterranean rainbow wrasse (''Coris julis'') is a small, colourful fish in the family Labridae. It can be found in the Mediterranean Sea and in the northeast Atlantic Ocean from Sweden to Senegal (though it is a rare wanderer to the southe ...

''. ''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 animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

, 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