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#phoronids

3 public questions tagged with this topic.

Animal Classification

Blood of phoronids contains

Phoronid circulatory physiology includes red blood corpuscles containing hemoglobin enabling oxygen storage and transport in often hypoxic burrow environments. Hemoglobin located inside nucleated corpuscles circulating within vascular lumen, not dissolved plasma as in some annelids, giving blood red coloration and high oxygen affinity. Corpuscular packaging improves carrying capacity and buffers pH. Trait parallels vertebrate erythrocytes and some polychaete blood cells considered convergent acquisition in lophophorate lineage enhancing gas exchange. Quantity and binding properties vary betwee

Ref: Ruppert et al., Invertebrate Zoology, Chapter 16: Phoronida blood corpuscles hemoglobin

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Animal Classification

Phoronids possess which type of circulatory system?

Phoronids despite small vermiform dimensions possess surprisingly well-developed closed vascular system distinguishing them from many colonial bryozoans. System includes two major longitudinal vessels: dorsal median collecting and ventral median distributing, plus transverse connectives and dense capillaries in lophophore tentacles, body wall, intestine and nephridia, propelled by contractility of vessels themselves rather than discrete heart. Blood remains confined within vessels ensuring high pressure flow allowing efficient oxygen transport. Contains extracellular hemoglobin. Closed conditi

Ref: Brusca & Brusca, Chapter 22: Phoronida closed circulation; Ruppert Invertebrate Zoology

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Animal Classification

Phoronids are commonly known as

Phoronida comprise small exclusively marine vermiform coelomate phylum commonly called horseshoe worms because lophophore typically forms horseshoe-shaped crown of hollow tentacles encircling mouth, especially in Phoronis ovalis though other species show spiral coil with many tentacles. Body differentiated into minute prosome, mesosome bearing lophophore, elongate metasome enclosed in self-secreted tubiculous chitinous tube often impregnated with sand, attached to hard substrate. Feed via ciliary downstream collection, possess U-shaped gut, closed circulation with hemoglobin, actinotrocha larv

Ref: Brusca & Brusca, Chapter 22: Phoronida horseshoe worms; Campbell Biology Lophophorata

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