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Acholoe

Acholoe Claparède is a genus under the kingdom of animalia, it belongs to family Polynoidae, which is a family of marine “scale worms” scientifically named as Polychaete worms. Members of family Polynoidea are named scale worms just because of their scale like appearance and dorsal surface. Under this family almost 900 species are recognized who come from next 9 subfamilies and 167 genera. Scale worms are known as the active daring hunters of the marine world. Generally this family dwells in defensive and protected environments like under the stones and rocks.

Acholoe Claparède

Acholoe Claparède is the direct child of Polynoinae Kinberg and its only species in the genus Acholoe is “Acholoe squamosa” which also belongs to the family of scale worms and it generally found in marine environment like in the Mediterranean Sea and the North-east Atlantic Ocean. Besides this, another species of Acholoe is Acholoe astericola which is not accepted yet.

Classification

Acholoe Claparède belongs to the kingdom of Animalia,

Annelida (Phylum), Polychaeta (Class), Errantia (Subclass), Phyllodocida (Order), Aphroditiformia (Suborder), Polynoidae (Family), Polynoinae (Subfamily), Acholoe (Genus) and Acholoe squamosa (species).

Description: Acholoe Claparède

Genus Acholoe Claparède has distinctive features like long body with several segments from 50 to more than 100 and numerous pairs of elytra on segments 2, 4, 5 & 7 and this sequence is repeated alternatively to 23, 26, 29, 32, segments and afterwards on every third segment to the end of the body.  Moreover, their prostomium is anteriorly rounded and without peaks while Prostomium is the cephalized first body segment in an annelid worm’s body at its anterior end. It looks like a small shelf like or lip like extension over the dorsal side of the mouth. Its lateral antennae are implanted ventrally. Squamosa have elongated acicular lobes with parapodias which refers to lateral outgrowths or protrusions from the body and they are generally found in annelids, where they are unjointed, paired and outgrowth bearing chaetae. Besides with Parapodia, they have both acicula (strong internal chaetae that provide support to parapodia) and penetrating epidermis. Elytra are found orbicular, smooth, without fringes of papillae, with scattered microtubercles on anterior part. Dorsal cirri are found on non-elytrigerous segments, with cylindrical cirrophores and distal styles; dorsal tubercles forming bi-furcated T-shaped ciliated branchial processes. Prostomium bilobed is present with 2 palps and 3 antennae with distinct ceratophores; median antenna inserted in anterior notch; ceratophores of lateral antennae inserted terminoventrally, converging midventrally (arctonoid type), with two pairs of eyes. First or tentacular segment is not distinct dorsally, with tentaculophores lateral to prostomium, achaetous, with dorsal and ventral tentacular cirri, without conical facial tubercle. Second or buccal segment is present with sub-rectangular nuchal lobe, while first pair of elytrophores, biramous parapodia, and ventral buccal cirri is longer than following ventral cirri. Parapodia biramous; notopodia short, subcoanical; neuropodia deeply cut dorsally and ventrally, with slightly longer bifid presetal acicular lobes and rounded postsetal lobes. Notosetae are found few in numbers, slender, short, curved, spinous, with blunt tips. Neurosetae are stout, falcate, spinous with entire tips. This genus has short and subulate ventral cirri, while Pharynx is found with nine pairs of papillae and two pairs of jaws. Additionally, commensal are found with asteroids, Pygidium is found with pair of anal cirri.

Remarks

Regarding the type species of Acholoe, there has ever been confusion, Hartman listed “Genotype: Acholoe squamosal (Della Chiaje) 1828, and Acholoe astericola as identical.

Species: Acholoe Squamosa

In annelids worms like Acholoe squamosa chaetae are found like bundles and arrays on the parapodia pairing appendages on the side of the body and are stout, with distinct rows of spines and blunt tips. The neurochatae which is a chitinous bristle is unidentate without secondary tooth at the tips. Their body is completely elongated, depressed, tapering slightly anteriorly and more posteriorly with several segments up to 120 or more. Elytra are found on large bulbous elytrophores covering dorsum. Elytra have large, oval, without papillae, with scattered microtubercles on anterior part and with yellow brown to blackish pigmentation in central part and near external borders.

Dorsal cirri is found on non-elytrigerous segments with short cylindrical cirrophores and tapering pappilate styles extending to tips of neurosetae. Dorsal tubercles are found in line with elytrophores forming large, flattened and T-shaped ciliated branchial processes. Bi-lobed prostomium is found with rounded lobes without cephalic peaks. While, median antenna is present with large ceratophore in anterior notch of prostomium with style, short and tapering tip. Similarly, lateral antennae is initiated with distinct ceratophores inserted terminoventrally while converging midventrally with short styles, subulate, stout palps, tapering, longer than median antenna, small eyes, larger anterior pair anterolateral and smaller posterior pair near posterior border.

Segment 2 is set up with rectangular bulbous area or nuchal fold between first pair of elytrophores; similar lobes on segments 3 and 4. Small biramous parapodia with ventral buccal cirri longer than following ventral cirri; notosetae and neurosetae similar to following segments and more slender.

Habitat: they are usually reported with various species of starfish in shallow depths of Atlantic Ocean, Mediterranean, English Channel, France, Spain and West Africa.