Classification of Porifera

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identifying characters
classification on the basis of spicules

1. Invertebrate Zoology Classification of Porifera CBCS-UGC syllabus (Zoology Hons) Presented by Mukesh Mandal ( M.Sc,B.Ed )

2. Classification of Porifera

3. Poris : Pore, Fera : to bear So the name Porifera refer to the species with many surface opening of the body. Defination : The phylum which includes multicellular cellular diploblastic invertebrates with ostia, osculum, paragastric cavity, mesenchyme, choanocyte , canal system and mesenchyme, is called Porifera .

4. Characters General characters: Symmetry: Radial or none Habitat: Aquatic (marine or fresh water) Identifying characters: Germ layer: They are diploblastic animal having only ectoderm and endoderm. In between them there is a gelatinous layer called Mesenchyme . Spicules: it is made up of calcium or silica . Canal system: well developed canal system present. Water enters into the body through ostia and goes out through osculum. Respiration: gaseous exchange take place through diffusion . Reproduction: asexual Nervous system: absent

5. Scheme of classification According to “Text book of Zoology” by Parker and hashwell (1972) Porifera Phylum Class Subclass Calcaria Or calcispongiae Hexactinellida Or Hyalospongiae Demospongiae Calcaronea Hexasterophora Ceractinomorpha Tetractinomopha Calcinea Amphidiscophora

6. Features of different taxa Class 1: Calcaria : Spicules or endoskeleton made up of calcium carbonate Large choanocyte cell present Subclass: 1. C alcaronea : Spicules with three rays . One ray is larger than the rest. Nucleus of choanocyte cell present in the upper portion. Eg : Sycon sp, Leucosolenia sp 2. Calcinea : Spicules with three rays . The rays are of same length . Nucleus of choanocyte cell present in the lower portion. Eg : Clathrina sp, petrobiona sp

7. Class 2: Hexactinellida : Spicules made up of silica. Vase or cup shaped body. Subclass: 1. Hexasterophora : Spicules with six rays. Eg : Euplectella sp ( venus flower busket ) 2. Amphidiscophora : Spicules with disk in both ends . Eg : Hyalonema sp

8. Class 3: Demospongiae Canal system complex type Spicules made up of silica. Subclass: 1. Tetractinomorpha : Spicules with four rays . Spongin fiber absent. Eg : Poterion sp, Cliona sp 2. Ceractinomorpha : Spicules with one rays . Spongin fiber present. Eg : Spongilla sp, Myxilla sp

9. Identify the following species Systematic position: Kingdom: Animalia Phyllum : Porifera Class : Calcaria Subclass : Calcaronea Identifying characters: 1. 2. Hence the species is ……..