PORT PHILLIP BAY


Pycnogonid 

Nymphon aequidigitatum Haswell, 1884

View scientific description and taxonomy

Scientific Details

Family level characters.
TRUNK: Elongate, typically with lateral processes well separated.
ABDOMEN: short, unsegmented at base.
EYES: 4
PROBOSCIS: short
SCAPES: One segmented.
CHELAE: Usually large, well developed, with teeth.
PALPS: 5-segmented (one genus has 4 segments).
OVIGERS: 10-segmented both sexes, compound spines and full strigilis, terminal claw present. No apophysis
LEGS: 8, 10 or 12 legs.
TARSUS: Shorter than propodus.
AUXILIARY CLAWS: Present or absent.
CEMENT GLAND: Ventral, rarely evident.
GENITAL PORES: Male, ventral surface coxa 2 legs 3 & 4; female all legs.

Genus level characters.
TRUNK: Usually elongate, segmented. Lateral processes well separated or crowded, setae, spines, glabrous and rarely with tubercles.
ABDOMEN: unsegmented.
EYES: Ocular tubercle at rear of cephalic segment.
PROBOSCIS: Short
SCAPES: One-segmented.

Taxonomy

Phylum:
Arthropoda
Subphylum:
Cheliceriformes
Class:
Pycnogonida
Order:
Pantopoda
Family:
Nymphonidae
Genus:
Nymphon
Species:
aequidigitatum

Other Names

  • Sea spider

General Description

Body with proboscis projecting outward from front, with the mouth at the tip. Central body (trunk) behind the proboscis, with a raised, rounded area (tubercle) bearing four eyes. Eight segmented walking legs attached to the sides of the trunk. Short abdomen behind trunk, unsegmented. Leg span about 4 cm.

Biology

Males brood the young which are found gathered on the body of the adult. This species is thought to breed in warmer months, with records of egg-bearing males present from December to April. Males carry the eggs, holding them between body parts called ovigers that hang under the animal.

Habitat

Usually under boulders and reef or on hydroids and seaweed in subtidal areas, sometimes in intertidal areas.

Reefs

Coastal shores

Distribution guide

South-eastern Australia, including western and central Victoria.

Species Group

Sea spiders

Depth

Shore (0-1 m)
Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

4 cm

Commercial Species

No

Global Dispersal

Native to Australia

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Staples, D.

David Staples is a consultant with expertise in pycnogonid taxonomy.

citation

Cite this page as:
Staples, D., 2011, Pycnogonid, Nymphon aequidigitatum, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 19 Aug 2017, http://portphillipmarinelife.net.au:8098/species/6252

Text: creative commons cc by licence