Ara
Arabescula Carter, 1873
- Arabescula parasitica Carter, 1873
Porifera → Demospongiae → Heteroscleromorpha → Heteroscleromorpha incertae sedis → Lithistida incertae sedis
Arc
Arcesios Duchassaing & Michelotti, 1864; nije prihvaćeno
- Arcesios hostilis Duchassaing & Michelotti, 1864
- Arcesios prominula Duchassaing & Michelotti, 1864
Porifera → Demospongiae → Heteroscleromorpha → Haplosclerida → Chalinidae
Are
Arenosclera Pulitzer-Finali, 1982
- Arenosclera arabica (Keller, 1889)
- Arenosclera brasiliensis Muricy & Ribeiro, 1999
- Arenosclera digitata (Carter, 1882)
- Arenosclera heroni Pulitzer-Finali, 1982
- Arenosclera parca Pulitzer-Finali, 1982
- Arenosclera rosacea Desqueyroux-Faúndez, 1984
Porifera → Demospongiae → Haplosclerida → Callyspongiidae
Art
Artemisina Vosmaer, 1885
- Artemisina amlia Lehnert, Stone & Heimler, 2006
- Artemisina apollinis (Ridley & Dendy, 1886)
- Artemisina archegona Ristau, 1978
- Artemisina arcigera (Schmidt, 1870)
- Artemisina clavata Lehnert & Stone, 2015
- Artemisina elegantula Dendy, 1924
- Artemisina erecta Topsent, 1904
- Artemisina flabellata Lehnert & Stone, 2015
- Artemisina incrustans Van Soest, Beglinger & De Voogd, 2013
- Artemisina indica (Thomas, 1974)
- Artemisina jovis Dendy, 1924
- Artemisina melana van Soest, 1984
- Artemisina melanoides Van Soest, Beglinger & De Voogd, 2013
- Artemisina plumosa Hentschel, 1914
- Artemisina stipitata Koltun, 1958
- Artemisina strongyla Hentschel, 1914
- Artemisina transiens Topsent, 1890
- Artemisina tubulosa Koltun, 1964
- Artemisina vulcani Lévi, 1963
Porifera → Demospongiae → Heteroscleromorpha → Poecilosclerida → Microcionidae → Ophlitaspongiinae
Arthuria Klautau et al., 2013
- Arthuria adusta (Wörheide & Hooper, 1999)
- Arthuria africana (Klautau & Valentine, 2003)
- Arthuria alcatraziensis (Lanna, Rossi, Cavalcanti, Hajdu & Klautau, 2007)
- Arthuria canariensis (Miklucho-Maclay, 1868)
- Arthuria darwinii (Haeckel, 1870)
- Arthuria dubia (Dendy, 1891)
- Arthuria hirsuta (Klautau & Valentine, 2003)
- Arthuria spirallata Azevedo, Cóndor-Luján, Willenz, Hajdu, Hooker & Klautau, 2015
- Arthuria sueziana (Klautau & Valentine, 2003)
- Arthuria tenuipilosa (Dendy, 1905)
- Arthuria tubuloreticulosa Van Soest & De Voogd, 2015
Porifera → Calcarea → Calcinea → Clathrinida → Clathrinidae