Depth
Centrostephanus · Echinoderms (Starfish, Urchins & Brittle Stars)

Hatpin Urchin

Centrostephanus longispinus

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Reef & Open
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Phylum Echinodermata
Genus Centrostephanus
Species longispinus

Echinoderm

Identification & Biology

  • IdentificationA striking sea urchin with an almost black test and exceptionally long, slender, needle-sharp spines that can reach 20 cm or more. The spines are banded in dark purple and white. One of the most recognisable echinoderms in the Mediterranean.
  • SizeTest diameter up to 7 cm. Spine length up to 25 cm, making the total diameter up to 55 cm.
  • Social HabitMostly nocturnal. Hides in crevices and cave openings during the day, emerging at night to graze on the reef. Often found in small groups.
  • HabitatRocky reefs, caves, and overhangs. Prefers shaded and dimly lit positions during the day.
  • Depth5 to 100 m. Most common between 10 and 50 m.
  • Feeds OnAlgae, encrusting organisms, and organic material scraped from rock surfaces.
  • DistributionMediterranean Sea and adjacent eastern Atlantic. Present in Maltese waters.
  • DescriptionCentrostephanus longispinus is the most dramatic-looking sea urchin in the Mediterranean, with its crown of long, sharp spines instantly recognisable in cave entrances and under overhangs. The spines can penetrate skin and break off, causing a painful wound. It is listed on Annex II of the Barcelona Convention as a protected species, and its collection is prohibited. It is primarily active at night.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting reef & open environments. Active from the surface down to 40m depth.

Where Malta divers have spotted this species

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Sightings are logged by divers using our What Did You See? dive-log tool. View the full live sightings map.

Detail

Preferred Environment

Reef & Open habitats, typically at depths of 0-40m. Most commonly encountered by divers at the shallower end of its range.

Encounter Tips

Best approached slowly and calmly. Avoid casting shadows directly over the animal. Neutral buoyancy and patience increase encounter success significantly.

Hatpin Urchin species card

Biology

Behaviour & Diet

Feeding Strategy

Omnivorous grazer that feeds on algae, sponges, and detritus using its Aristotle's lantern. Forages on rocky substrates and among Posidonia beds.

Omnivorous grazer

Reproduction

Sexes are separate, with synchronised broadcast spawning releasing gametes into the water column. Larvae develop through a planktonic pluteus stage.

Broadcast spawner

Behaviour & Defence

Possesses extremely long, slender, needle-like spines that can exceed 20 cm, inflicting painful wounds. Spines are mildly venomous and can break off in tissue, causing irritation.

Venomous spines

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Centrostephanus longispinus. All are accessible on a guided dive with diveshack.

5-30m
North Malta

Cirkewwa

Rocky reef with caves, arches and ledges hosting a rich diversity of reef species.

View dive site ›
5-50m
Gozo

Blue Hole

One of the Med's most famous reef dive sites. Rocky walls and archways covered in life.

View dive site ›
18-36m
South Malta

Um El Faroud

The wreck lies on a sandy bottom surrounded by rocky reef -- a diverse habitat attracting reef species.

View dive site ›
IUCN Red List Least Concern

Conservation Status

This species is assessed as Least Concern on the IUCN Red List. Mediterranean populations face ongoing pressure from fishing activity, habitat degradation, and climate-driven changes to prey availability.

Source: iNaturalist Guide #888
by Lesley Clements (CC BY-SA)
diveshack Mediterranean Marine Life guide