The chromosome number distribution was consistent with the presence of at least six sympatric euploid chromosome complements (one diploid, one triploid, three tetraploids and one hexaploid), as confirmed by a FISH assay performed with an homologous 18S rDNA probe. To generate a robust phylogeny enabling the reconstruction of the evolutionary processes shaping the diversity of these sympatric lineages, we complemented our original 16S rRNA gene sequences with additional COI sequences. For each cocoon, we sequenced a fragment of the 16S rRNA from half of the sibling embryos and karyotyped the other half. To gain insights into the evolutionary events that generated this differentiation, we performed a cytogenetic analysis in parallel with a molecular assay.
from the Lambro River (Milano, Italy), which we suggested comprise several cryptic species. In a molecular phylogenetic analysis, we detected substantial genetic variability among sympatric Tubifex spp. Tubifex worm are often used as a live food for fish, especially tropical fish and certain other freshwater species.Tubifex tubifex is a widespread annelid characterized by considerable variability in its taxonomic characteristics and by a mixed reproductive strategy, with both parthenogenesis and biparental reproduction. Contractile heart is found in the 8th segment. Clitellum is formed in the 11th and 12th segments.Ħ. Setae Forked and hair-like in dorsal bundles and only forked in Ventral bundles.ĥ. Each body segment except the last few are provided with four bundles of setae on the dorsal and ventral sides.ģ. Tubifex is a small slender worm, measuring about 4 cm in length and reddish in color.Ģ. The animal lives in tubes made up of mud and minerals glued together by mucin.ġ.
Habit and Habitat: Tubifex is a fresh water form, occurs in patches on the muddy bottom in the freshwater ponds and lakes. Arenicola is generally used as bait in fishing.Īrenicola can be beneficial by negatively impacting the population of small rodents and insects. Posterior region or post branchial region is much thinner consisting of a variable number of segments devoid of parapodia setae and gills.Ĩ.
Middle region or branchial region comprises thirteen segments bearing parapodia and branched gills.ĥ. Body is divisible into three regions, anterior middle and posterior.Ĥ. Body is stout, elongated, cylindrical worm- like measuring up to 20 to 25 cm in length and brownish or greenish in color.ģ. Arenicola is commonly known as lug warm or lobe-worm.Ģ. It is found in Mediterranean and European shores.ġ. Habit and Habitat: Arenicola is a marine worm that lives in U-shaped burrows of sand and mucus. Distribution: Arenicola is distributed in Europe and the U.S.A.
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