CLASSIFICATION OF PHYLUM PORIFERA

Published in Zoology
Monday, 17 April 2017 00:14
Phylum porifera is classified mainly basing on skeleton. It is divided into 3 classes. sponges spicules plays a very important role in classification of porifera.
  1. Class: Calcarea
  2. Class: Hexactinellida
  3. Class: Demospongiae
CLASS I : CALCAREA:
  1. Skeleton is made by calcareaous spicules.
  2. They show single spongocoel cavity which opens to the outside through a single opening called osculum.
  3. Radially symmetrical animals.
  4. Choanocyte cells are large.
This is divided into 2 orders.
 
Order 1 : Homocoela:
1. Spongocoel is lined by choanocytes internally.
2. Simple sponges or included in this order.
Ex: Clathrina, Leucosolenia, Olynthus.
 
Order 2 : Heterocoela
1.Spongocoel is lined by epithelial cells.
2.Choanocytes restricted to radial canals only.
3. Leuconoid or Syconoid canal system is seen.
Ex: Sycon, Grantia.
 
CLASS II : HEXACTINELLIDA (OR) HYALOSPONGIAE:
  1. Skeleton contains six rayed, or triaxon, siliceous spicules.
  2. Radially symmetrical.
  3. These are also known as glass sponges.
This class includes 2 orders
 
Order 1. Hexasterophora :
1. The spicules are of hexasters type.
2. They are attached to hard objects.
Ex: Euplectella
 
Order 2. Amphidiscophora :
1. The spicules are amphidiscs.
2. These sponges are attached to the substratum by root tufts.
Ex: Hyalonema, Glass rope sponge
 
CLASS III : DEMOSPONGIAE:
  1. Skeleton either absent or present.
  2. The skeleton contains spongin fibres or silicious spicules or both.
This class is divided into 3 subclasses.
 
Subclass 1. Tetractinellida:
  1. The skeleton consists of tetraxon spicules or without spicules.
  2. They are mostly solid rounded structures.
  3. Leuconoid canal system is present. This subclass is divided into three orders.
Order 1. Myxospongida:
1.Structure is simple
2.Skeleton is absent.
Eg. Oscarella
 
Order 2. Carnosa (or) Homosclerophora:
1. Equal sized spicules are present.
2. Megascleres and microscleres are not sharply differentiated.
Ex: Plakina.
 
Order 3. Choristida:
1. Microscleres and megascleres are distinct.
Eg. Tetilla, Geodia.
 
Subclass 2. Monaxonida:
  1. Skeleton consists of monaxon spicules.
  2. Spongin fibres may or may not be present.
  3. They are cosmopolitan in their distribution.
  4. Shallow or deep water forms. This subclass includes 3 orders.
Order 1. Hadromerida:
Spongin fibres absent.Monaxon spicules are represented by tylostyles.
Eg. Cliona (Boring sponge), Tethya.
 
Order 2. Halichondrida:
Monaxon spicules are seen.
Eg. Halichondria.
 
Order 3. Poecilosclerida:
Monaxon spicules are present. Microscleres are sigmas, toxas etc.
Eg. Microciona.
Advertisement

Useful Sites

  • NCBI

    National Center for Biotechnology Information
  • LTO

    Lab Tests Online® by AACC
  • ASCP

    American Society for Clinical Pathology
  • ASM

    American Society for Microbiology
  • The Medical Library®

    Project of BioScience.pk
Advertisement

Connect With Us

Contact Us

All comments and suggestions about this web site are very welcome and a valuable source of information for us. Thanks!

Tel: +(92) 302 970 8985-6

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Website: https://www.bioscience.pk



This website is certified by Health On the Net Foundation. Click to verify. This site complies with the HONcode standard for trustworthy health information:
verify here.

Our Sponsors

InsightGadgets.comPathLabStudyTheMedicalLibrary.orgThe Physio ClubB2BPakistan.com

By using BioScience.pk you agree to our use of cookies to enhance your experience on this website.