Giant Clams and Marine Bivalves Codexery

Maxima clam

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Maxima clam

Diego Delso · via Wikipedia: Maxima clam · CC BY-SA 4.0

Throughout the Indo-Pacific, one finds the bivalve mollusc species Tridacna maxima, referred to as the maxima clam or small giant clam.[1] Compared to Tridacna gigas, the true giant clam, the maxima clam's size is less than one-third of that species.[2] The shell edges, marked by prominent furrows, are hidden when the clam opens and exposes a mantle that is bright blue, green, or brown.[3]

Scientific classification

  1. KingdomAnimalia
  2. PhylumMollusca
  3. ClassBivalvia
  4. OrderCardiida
  5. FamilyCardiidae
  6. GenusTridacna
  7. SpeciesTridacna maxima

Named by Röding, 1798

Close relatives

Other species of Tridacna with a Codexery entry.

Sources: Wikipedia taxobox: Maxima clam (CC BY-SA 4.0) · order, family and genus agree with WoRMS AphiaID 207675 (CC BY 4.0)

Conservation status

Least Concern (LC)

  1. LC▲ this species
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX
Population trend
Not held in our sources — see the assessment
Assessment published
2024

Source: IUCN Red List assessment · GBIF copy of the Red List category

Where the maxima clam has been recorded

Where the maxima clam has been recorded239 mapped locations from 23,839 GBIF occurrence records

Each dot is a place where the species has been observed and reported (23,839 records, half-degree grid) — not a modelled range. 22 inland records left out (institution coordinates).

Map: drawn by Codexery. Data: GBIF occurrence search (records CC0 / CC BY) · Natural Earth basemap (public domain)

Key facts and history

It obtains most nutrients from tiny photosynthetic algae called zooxanthellae, reducing its need to filter-feed.[2] Among all giant clam species, the small giant clam occupies the most extensive geographic range.[4] Because it depends on symbiotic photosynthetic algae that need sunlight, the small giant clam lives in well-lit spots on reef surfaces, sand, or partly embedded in coral.[5] A fertilized egg of this species becomes a free-swimming larva after hatching within 12 hours.[2]

Metamorphosis from larva to juvenile clam occurs after eight to ten days, at which point the juvenile can take in zooxanthellae.[2] After two or three years the juvenile matures as a male; once it reaches about 15 centimeters in length it becomes a hermaphrodite.[2]

What the cited sources add

Crystalline pigment cells are what produce the small giant clam's attractive colors.[3] These cells are believed to either shield the clam from strong sunlight or focus light to improve photosynthesis by the algae.[3] To prevent self-fertilization, hermaphroditic clams release sperm before they release eggs.[2]

References

  1. Wikipedia, "Maxima clam" (CC BY-SA 4.0), which cites: MolluscaBase eds. (2022). MolluscaBase. Tridacna maxima (Röding, 1798). Accessed through: World Register of Marine Species at: https://marinespecies.org/aphia.p (original not read by us) en.wikipedia.org
  2. Wikipedia, "Maxima clam" (CC BY-SA 4.0), which cites: Ellis, S. (1998) Spawning and early larval rearing of giant clams (Bivalvia: Tridacnidae). Center for Tropical and Subtropical Aquaculture, 130: 1–55. (original not read by us) en.wikipedia.org
  3. Wikipedia, "Maxima clam" (CC BY-SA 4.0), which cites: Ellis, S. (1998) Spawning and early larval rearing of giant clams (Bivalvia: Tridacnidae). Center for Tropical and Subtropical Aquaculture, 130: 1–55.; "Giant clams could inspire better color displays and solar cells", www.gizmag.com, January 20, 2016 (original not read by us) en.wikipedia.org
  4. Wikipedia, "Maxima clam" (CC BY-SA 4.0), which cites: Neo, "Tridacna maxima", 2024; Huelsken, T., Keyse, J., Liggins, L., Penny, S., Treml, E.A., Riginos, C. (2013) A Novel Widespread Cryptic Species and Phylogeographic Patterns within Several (original not read by us) en.wikipedia.org
  5. Wikipedia, "Maxima clam" (CC BY-SA 4.0), which cites: Wells, S.M., Pyle, R.M. and Collins, N.M. (1983) The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland.; Ellis, S. (1998) Spawning and early larval rearing of giant clams (Bivalvia: Tridacnidae). Center for Tropical and Subtropical Aquaculture, 130: 1–55. (original not read by us) en.wikipedia.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Maxima clam (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

More in Giant Clams and Marine Bivalves

Tridacna noaeTridacna rosewateriTridacna squamosaTridacna squamosinaArgopecten gibbusArgopecten irradiansArgopecten purpuratusChlamys hastataChlamys rubidaTridacninaeHippopusHippopus hippopus

Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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