Astroceramus astrikos
A stout, pentagonal sea star from deep waters off New Caledonia.
Astroceramus astrikos, a sea star from the family Goniasteridae, lives off the coast of New Caledonia. Its body is stout and roughly pentagonal, with short arms and straight edges between them. The species name comes from the Greek for "of the stars."
This sea star closely resembles the Hawaiian species Astroceramus eldredgei, sharing short arms and wide, adjoining upper marginal plates. However, A. astrikos has fewer of these plates: only 2 to 3 per arm, compared to 4 to 6 in A. eldredgei. It also has fewer marginal plates between the arm tips—6 to 8, versus 12 to 16. The granules on its underside are finer, and the spines along the furrow and next to it are smaller and thinner.
The upper surface plates are polygonal or round, each bearing 40 to 200 crystalline bumps. The upper marginal plates meet across the arm’s midline, with 2 to 3 per arm and 6 to 10 total from one arm tip to another. Each marginal plate is covered by 40 to 250 evenly spread granules. The lower marginal plates have small, paddle-shaped pedicellariae with 4 to 6 interlocking teeth. The underside plates are covered by coarse, round granules (3 to 20 per plate) and 1 or 2 paddle-like pedicellariae. Along the furrow, there are 5 to 6 flattened spines with wide, blade-like tips. Next to these are 3 or 4 subambulacral spines, with one long pedicellaria in the middle.
This species is found at depths between 370 and 621 meters near New Caledonia.
Quick Facts
- Genus
- Astroceramus
- Species
- astrikos
Facts from the source article.
Lore & Background
The species epithet astrikos is Greek for 'of the stars'. In taxonomy and systematics, Astroceramus astrikos displays an immediate resemblance to the Hawaiian Astroceramus eldredgei in having relatively short arms with wide, abutted superomarginals and a low R/r ratio. However, A. astrikos displays consistently fewer superomarginals (2 to 3 abutted plates per arm versus 4 to 6 in A. eldredgei) and fewer marginal plates per interradius (6 to 8 versus 12 to 16 in A. eldredgei). Actinal granulation is coarser in A. eldredgei, and its furrow and subambulacral spines are larger and thicker.
The species has a stout, weakly stellate to pentagonal body with short arms and straight interradial arcs. Abactinal plates are polygonal to round, with 40–200 crystalline bosses embedded in each plate surface. Superomarginal plates are abutted over the midline for the entirety of the arm, composed of 2 to 3 plates; there are 6 to 10 marginal plates per interradius (arm tip to arm tip). Individual marginal plates are covered by 40–250 evenly distributed granules. Inferomarginals have small paddle-shaped pedicellariae with valves bearing 4 to 6 interclasping teeth. Actinal plates are covered by coarse, round granules (3 to 20 per plate) and 1 or 2 paddle-like pedicellariae. Furrow spines number 5 to 6 (primarily six), are strongly flattened with blade-like, wide tips. Subambulacral spines immediately adjacent to the furrow number 3 or 4, with one prominent elongate pedicellariae present median to the others.
Reader's Guide
Astroceramus astrikos is significant as a deep-sea species from the family Goniasteridae, documented only off New Caledonia at depths of 370 to 621 meters. Its description provides detailed morphological distinctions from the similar Hawaiian species Astroceramus eldredgei, particularly in the number of superomarginal plates and marginal plates per interradius, as well as differences in actinal granulation and spine size. The species' stout, pentagonal body and short arms, along with its crystalline bosses on abactinal plates and paddle-shaped pedicellariae, contribute to the taxonomic understanding of the genus Astroceramus. Its Greek epithet 'astrikos' meaning 'of the stars' ties it to a broader tradition of celestial nomenclature in starfish taxonomy. The species' legacy lies in its role as a distinct deep-water representative of the Goniasteridae, with its morphological features helping to clarify relationships within the genus and distinguish it from its Hawaiian relative.
Did You Know?
- Astroceramus astrikos has 2 to 3 superomarginal plates per arm, compared to 4 to 6 in Astroceramus eldredgei.
- Its furrow spines number 5 to 6 and are strongly flattened with blade-like, wide tips.
Frequently Asked Questions
Who is Astroceramus astrikos?
Astroceramus astrikos is a deep-water sea star belonging to the family Goniasteridae, found exclusively off the coast of New Caledonia. It is a stout, roughly pentagonal species with notably short arms and straight edges connecting them.
Where and how deep does Astroceramus astrikos live?
This species inhabits the deep ocean off New Caledonia, typically at depths between 370 and 621 meters. It is a benthic organism restricted to that specific geographic region.
What does Astroceramus astrikos look like?
It has a compact, pentagonal body with short arms and straight interradial edges. Its upper surface carries 2 to 3 superomarginal plates per arm, 6 to 10 marginal plates in each interradius, and 5 to 6 furrow spines (most commonly six).
How is Astroceramus astrikos different from the similar A. eldredgei?
Although both share short arms and broad, adjoining upper marginal plates, A. astrikos has noticeably fewer of these plates—only 2 to 3 per arm versus 4 to 6 in the Hawaiian A. eldredgei. It also bears fewer marginal plates between arm tips, with 6 to 10 compared to 12 to 16 in its relative.
What does the name Astroceramus astrikos mean?
The specific epithet 'astrikos' derives from the Greek word meaning 'of the stars,' a nod to the creature's star-shaped body plan. The genus name Astroceramus similarly evokes a star-like form.
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