PYCNOGONOIDEA

Patricia Nicole M. PerezBSBIO3A

Mrs. Virginio

Pycnogonidea or Pantopoda

(sea-spiders) are a group of marine arthropods.

Kingdom: AnimaliaPhylum: ArthropodaSubphylum: ChelicerataClass: Pycnogonida

Anatomy of a pycnogonida:

A. head; B. thorax; C. abdomen

1. proboscis; 2.chelifores;

 3. palps; 4.ovigers; 5. egg sacs; 6a–6d: four pairs of legs

Characteristics

• The body is slender, segmented, and divided into two regions, the head and the trunk.

•  The head features a number of pairs of appendages, including two pairs of feeding appendages (chelifores) with pincers at the tips, a proboscis with the mouth at the end, and both sexes have a pair of egg-carrying 'legs‘.

• The trunk bears four pairs of long, spindly legs, and has a small projection at the rear called the abdomen

• There are more 1300 species of pycnogonids described and it is believed there are many more species to be discovered mainly from remote deep-sea habitats. The known species are traditionally distributed in 80 genera and eight or nine families as they are: Ammotheidae, Austrodecidae, Callipallenidae, Colossendeidae, Nymphonidae, Phoxichilidiidae, Pycnogonidae, Rhynchothoracidae, and Endeididae a monogeneric family sometimes included in Phoxichilidiidae.

Habitat• Sea spiders usually live near the shore. • They are found crawling over seaweeds as well

as on sea anemones, small sea animals with long, thin, armlike body parts called tentacles corals, the hard skeletons of certain sea creatures; and other animal colonies, or tight groupings of animals, permanently attached to the sea bottom.

• Some species are found at great depths, up to 23,000 feet (7,000 meters), where they live near hot water springs bubbling up from the sea floor.

Location

• They are cosmopolitan, found especially in the Mediterranean  and Caribbean Seas, as well as the Arctic and Antarctic Oceans.

• There are over 1300 known species, ranging in size from 1 to 10 millimetres (0.039 to 0.39 in) to over 90 cm (35 in) in some deep water species.

Life Cycle• Pycnogonids do not have a planktonic stage in their

life cycle, and this is believed to have implications for the patterns of distribution and a possible high rate of speciation. In species of callipallenids and nymphonids the larvae stay attached to the parent's ovigers until they reach a well-developed stage (after the fourth instar) (Nakamura 1981). Pycnogonid protonymphs resemble a nauplius larva of the crustaceans, but they have a proboscis, bear chelifores with strong pincers, and have two other pairs of appendages with a single terminal claw. There is little information to date on morphological characters of larvae and juvenile stages.

ExamplesNymphon gracile

Kingdom: Animalia

Phylum: Arthropoda

Class: Pycogonida

Order: Pantopoda

Family: Nymphonidae

Genus: Nymphon

• Scientific Name: Nymphon gracile• Location: Hitra, Norway• Has a smooth body up to 1 cm long.• Body length up to 10 mm.

Pycnogonum stearnsi

 Kingdom: Animalia 

Phylum: Arthropoda

Class: Pycnogonida 

 Order:Pantopoda

  Family: Pycnogonidae

 Genus: Pycnogonum

 Species:Pycnogonum

stearnsi

• Scientific Name: Pycnogonum stearnsi• Location: Fitzgerald Marine Reserve,

Moss Beach, California, USA• Description color white to pale

yellowish-white. Proboscis barrel-shaped, without bumps or swellings. Legs relatively short, without tubercles.

• Size: Typically about 5mm in length; leg span up to about 10mm.

Anoplodactylus evansi 

Kingdom:

Phylum:

Animalia

Arthropoda

Class: Pycnogonida

Family: Phoxichilidiidae

Genus: Anoplodactylus

Species: Evansi

• Habitat: Red algae in rock pools and on subtidal reef, to depth of 16 m.

• Identifying Characters: Body mainly red, with blue markings. Yellow around the leg joints. Body up to 1 cm long.