---
title: Nail-armed Sea Star (Mithrodia clavigera)
scientific_name: Mithrodia clavigera
common_name: Nail-armed Sea Star
taxon: Starfish
published: 2026-08-06T16:37:23.107Z
updated: 2026-08-15T20:34:24.099Z
tags: Nail-armed Sea Star, Mithrodia clavigera, Starfish, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/echinoderms/starfish/nail-armed-sea-star
---

# Nail-armed Sea Star (*Mithrodia clavigera*)

## Quick facts

- **Group:** Starfish (*Asteroidea*)
- **Size:** up to 60 cm
- **Depth:** 3-40 m
- **Diet:** Carnivore
- **Activity:** Nocturnal
- **Rarity:** Rare
- **Habitat:** Reef slopes and rubble, in the open at night
- **Reproduction:** Broadcast spawner, Gonochoric

## How to recognise it

- five long thin cylindrical arms, much narrower than the disc suggests
- surface covered in blunt club-shaped spines, like nails driven into the skin
- red-brown to orange, often mottled
- arm span up to 60 cm

Five long cylindrical arms studded with blunt club-shaped spines, spread across a reef slope at night. Sixty centimeters (24 in) across at full size, and rarely seen because it moves only after dark.

The arms are the interesting part. They are unusually long, thin and flexible for a sea star, and they detach readily - this species is one of the champions of arm loss and regrowth, and individuals with arms at four different lengths are the rule rather than the exception. A shed arm can, in some sea stars of this general kind, regenerate an entire animal from the fragment alone.

It feeds slowly on encrusting animals and detritus, everting its stomach over them the way sea stars do, digesting outside the body and absorbing what is left.

Underneath, hundreds of tube feet run in grooves along each arm, worked by a hydraulic system with no heart and no brain - seawater pumped through a ring of canals, which is how the whole animal moves.

## Also known as

- **English:** Old Club Sea Star, Nail Sea Star
- **French:** Etoile de mer cloutée
- **Japanese:** フトトゲヒトデ
- **Chinese:** 棒棘海星
- **Russian:** Гвоздистая звезда

## Scientific synonyms

- *Asterias clavigera* Lamarck, 1816
- *Echinaster echinulatus* (Muller & Troschel, 1842)
- *Heresaster papillosus* Michelin, 1844
- *Mithrodia echinulatus* (Müller & Troschel, 1842)
- *Mithrodia spinulosa* Gray, 1840
- *Mithrodia victoriae* Bell, 1882
- *Ophidiaster echinulatus* Müller & Troschel, 1842

## Range

Bahamas, Caribbean Sea, Cuba, Eastern Africa & Madagascar, Gulf of Mexico, Guyanas, Indian Ocean, Mexico, New Caledonian Exclusive Economic Zone, Palau, Red Sea, Seychelles, South Atlantic Ocean, South Pacific Ocean, Tanzania

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/echinoderms/starfish/nail-armed-sea-star)*
*Updated: August 15, 2026*