PORT PHILLIP BAY


Pycnogonid 

Anoplodactylus spinirostrum Stock, 1973

View scientific description and taxonomy

Scientific Details

Family level characters.
TRUNK: With anterior extension of cephalic segment over-reaching base of proboscis.
ABDOMEN: Short to moderately long, inclined dorsally.
EYES: 4
PROBOSCIS: variably shaped, about as long as scapes.
SCAPES: 1-segmented
CHELAE: small, functional
PALPS: lacking entirely or rarely with small palp buds
OVIGERS: 5- or 6-segmented, present in male only, without strigilis or terminal claw.
LEGS: 8 legs. Many species possess a unique propodal lamina.
TARSUS: Shorter than propodus.
AUXILIARY CLAWS: Auxiliary claws either absent or present. They may be tiny and placed lateral to main claw or larger and palced distal to main claw.
CEMENT GLAND: duct(s) conspicuous on dorsal femur.
GENITAL PORES: Male, ventral surface of coxae 2 of legs 3 & 4, opening on top of tall spur. Female pores on ventral surface of second coxae of all legs, no spur.

Genus level characters.
TRUNK: Trunk & legs usually slender. Segmentation often indistinct, particularly between segments 3 & 4. Cephalon strongly projecting over basal part of proboscis.
ABDOMEN: Prominent and erect.
EYES: Rarely blind. Tubercle usually high, pointed.
PROBOSCIS: Usually cylindrical.
SCAPES: Small, 1-segment, longer than proboscis.

Taxonomy

Phylum:
Arthropoda
Subphylum:
Cheliceriformes
Class:
Pycnogonida
Order:
Pantopoda
Family:
Phoxichilidiidae
Genus:
Anoplodactylus
Species:
spinirostrum

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. Prominant, erect abdomen behind trunk. Leg span to 6 mm.

Biology

Possibly because of its small size and subtidal habitat, this species is rarely seen by divers. Males carry the eggs, holding them between body parts called ovigers that hang under the animal.

Habitat

On bryozoans and hydroids, at depths between 10 and 20 m.

Reefs

Distribution guide

Western Port and Port Phillip in Victoria.

Species Group

Sea spiders

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

6 mm

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, Anoplodactylus spinirostrum, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Feb 2025, http://136.154.202.208:8098/species/6248

Text: creative commons cc by licence