Learning Bio-Etymology- Part 9 – ANNELIDA

·       Eucoelomate: [Gk. eu = true, well, good + koiloma / koilia = hollow, cavity]

In all the higher bilateria, from Annelids onwards, the blastocoel gets obliterated by the development of endodermal ‘archenteron’ [embryonic gut] and another space (true coelom or eucoelom) is created between two layers of mesodermal cells (peritoneum) present between the gut (endoderm) and the body wall (ectoderm).

Examples: Annelida to Chordata. ……………… Bio-etymology PART – 9 onwards.

For the types of Coelom in ‘Bilateria’, please refer to 

                                   Bioetymology PART – 5 

·       Digestive system complete and straight.

·       Blood vascular system closed type with haemoglobin dissolved in plasma.

·       Respiration through moist skin or gills.

·       Nervous system with a circumenteric ring and 2 ventral nerve cords. [Lain circum = round, around + Gk. enteron = gut / alimentary canal] i.e., the part of central nervous system made of highly ganglionated ‘nerve ring’ encircling the pharynx.

·       Sensory organs include tactile organs, taste buds, statocysts, photoreceptor cells or eyes in some.

·       Dioecious or monoecious.

Dioecious: [Gk. di = two + oiki (on) or oikos = house]; male and female reproductive organs (Gonads) at two separate places i.e., male and female individuals.

Or

Monoecious: [Gk. mono = one + oiki (on) or oikos = house]; male and female reproductive organs (Gonads) are in one individual (bisexual or hermaphrodite).

·       Fertilization internal or external. Development direct or indirect.

Based on the presence, absence and number locomotory organs called, ‘setae’, the Phylum is divided into 4 Classes. Further, division of Classes into Subclasses and then into Orders is based on living habit, reproductive organs or location of gonopores or presence or absence of jaws on the proboscis.

Class – Polychaeta: [Gk. poly = many + khaite / chaeta = long hair, (chitinous) bristle or setae] i.e, the worms having many locomotory bristles like seate; placed on lateral fleshy extensions of skin of every segment called, Parapodia [Gk. para = at or to one side of, side by side + podos or pod = foot ].

Subclass- Errantia: [L. errare, to wander, roam, ramble] i.e., wandering or free-living Polychaetes.

EXAMPLE(S):

·        Aphrodite (Sea Mouse): [Gk. aphrodite = ancient goddess of love] i.e., supposed to be named on account of its resemblance with human female genitalia. Common name ‘sea mouse’ is due to its resemblance to a wettened house mouse when washed ashore.

[Ref.: https://www.metmuseum.org/art/collection/search/254697; https://www.earthtouchnews.com/natural-world/how-it-works/this-rainbow-wonder-is-one-of-the-worlds-weirdest-worms/; https://www.faunafondness.com/aphrodita-sea-mouse/]

·        Nereis (Clamworm, Sand Worm): [Ancient Gk. Nereis = sea nymph or Nereus = the sea-god Nereus] i.e., a name applied to his daughters by Doris, who were regarded by the ancients as marine nymphs of the Mediterranian , in contra-distinction from the ‘Naiades’ or the nymphs of fresh water  and ‘Oceanides’ or the nymphs of the great ocean. Another explanation is ‘The Nereides were 50 sea-nymph daughters of Nereus, the old man of the sea. They were goddesses of sea’s rich bounty and protectors of sailors and fishermen, coming to the aid of those in distress’.

Common name ‘clam worm’ and ‘sand worm’ arises out the fact they live in burrows in sand or mud, often with ‘clams’ (a common name for several kinds of bivalve Molluscs).

[Ref.: https://www.flickr.com/photos/a_semenov/6514998793; https://chess.myspecies.info/file-colorboxed/360; https://www.allamaiqbalcollege.edu.in/uploads/download_2005300555.pdf]

Subclass – Sedentaria: [L. sedens or sedentarius = sitting, tending to sit around a lot] i.e., sedentary Annelids or those which are not freely moving but living inside burrows.

EXAMPLE(S):

·        Chaetopterus (Parchment worm or parchment tube worm or paddle worm): [Gk. chaeta / cheta / chaetae = chitinous bristle(s) or setae + pteryx = wing] i.e., the common name ‘parchment worm’ arises from the parchment-like U-shaped tubes (made in the sand or mud) in which the worm lives; and ‘paddle worm’ arises from paddle-like parapodia creating a feeding current of water propelled by fan-like (wing-like) parapodia, particularly aliform or wing-like parapodia  of 10^th segment and 3 sets of parapodial fans  of the middle region.

[Ref.: https://library.ucsd.edu/dc/object/bb04788169; https://alchetron.com/Chaetopterus]

·        Arenicola (Lugworm): [Gk. arena = sand + colo = to inhabit] i.e., living or burrowing in sand.

[Ref.: https://commons.wikimedia.org/wiki/File:Arenicola_marina_poliqueta_sedentario.png; https://commons.wikimedia.org/wiki/File:Arenicola_marina.JPG; https://epadigestive.weebly.com/lugworm-arenicola-marina.html]

·        Amphitrite: [Gk. amphi = round about, on both sides + trite = third] i.e., meaning thereby ‘three times around’, perhaps on account of posteriorly coiled forms of the specimens. In Greek mythology, ‘Amphitrite’ is the name of a daughter of Nereus and Doris. Some considered her a personification of sea itself. She was the wife of Poseidon. Poseidon and Amphitrite had a son ‘Triton’, the Greek God of the sea, used to live in a golden palace on the bottom of the sea. Triton’s special attribute was a twisted sea shell  (‘conch shell’), on which he blew to calm or raise the waves.

Triton is also represented as a ‘merman’ (the male equivalent of mermaid), with the upper body of a human and tailed lower body of a fish. At some places, Amphitrite was depicted in Greek vase painting as a young woman, often raising her hand in a pinching gesture. In mosaic art the goddess usually rides beside her husband in a chariot drawn by fish-tailed horses or ‘hippokampoi’. Sometimes her hair is enclosed with a net and her brow adorned with a pair of crab-claw ‘horns’

[vide:https://www.theoi.com/Pontios/Amphitrite.html; https://www.greekmythology.com/Other_Gods/Amphitrite/amphitrite.html].

The similarity of the animal ‘Amphitrite’ with the sea Goddess ‘Amphitrite’ comes from the fact that, The long, filiform ‘tentacles’ on the peristomium and branched ‘gills’ on first three segments provide appearance similarity with ‘hair’ of the goddess.

The posterior coiled end of ‘Amphitrite’ perhaps resembles ‘twisted seashell of Triton’ or ‘fish-tailed horses or ‘hippokampoi’.

[Ref.: https://www.faunafondness.com/amphitrite/; https://commons.wikimedia.org/wiki/File:Terebellidae_(YPM_IZ_080460)_002.jpeg]

Class – Oligochaeta (Clitellata): [GK. oligos = few + khaite / chaeta = long hair, (chitinous) bristle or setae] [L. clitellae = a pack-saddle + ate(a) = possessing, having the appearance of or a group having a certain function] i.e., the worms (Oligochaeta) having fewer setae (than Polychaeta), embedded in the skin.

Alternatively, the worms (Clitellata) having a thickened glandular section of body wall and secreting a viscid sac in which the eggs are deposited [literally it is meant ‘a pack-saddle’ because a saddle is specifically designed for holding or supporting the load on a ‘pack’ animal (= sumpter animal or beast of burden, a working animal used for transporting material by attachning them so that their weight bears on the animal’s back]. 

Order – Plesiopora (Plesiothecata): [Gk. plesion = near + porus = pore + theke = case + ate(a) = possessing, having the appearance of or a group having a certain function] i.e., indicating about most ‘tube-dwelling’ worms having the ‘male gonopores’ on the segment immediately following (or near) that which contains ‘testes’ or ‘spermathecae’ in the testes-containing segments or ‘nearby’.

EXAMPLE(S):

·        Tubifex: [L. tubus = tube + facere = make] i.e., a freshwater worm living in ‘tubes made of mud’ at the muddy bottoms of lakes, ponds and streams.

[Ref.: https://killifish.biz/product/sealed-live-tubifex-in-bulk/;https://alchetron.com/Tubifex-tubifex; https://www.waterwereld.nu/tubifexeng.php;]

Order – Prosopora: [Gk. pro = before+ porus = pore] i.e., indicating about some (parasitic) worms having the ‘male gonopores’ anterior (pro-) to female pores; on the same segment or on the segment containing the second pair of testes. 

EXAMPLE(S):

·        Branchiobdella: [Gk. branchia = gill(s) + bdella = leech] i.e., a small parasitic worm living on the ‘gills’ of a crayfish attached by a ‘sucker’ (the posterior end modified into an adhesive sucker; like a ‘leech’).

  [Ref.: https://en.wikipedia.org/wiki/Branchiobdellida; https://www.kmae-journal.org/articles/kmae/pdf/2002/03/kmae200236711.pdf; http://nonchordatesworld.blogspot.com/2016/11/phylum-annelida.html

Order – Opisthopora: [Gk. opisthe =  behind, opposite + porus = pore] i.e., indicating about most terrestrial burrowing worms having the ‘male gonopores’ some distance ‘behind’ the testes-bearing segments.

EXAMPLE(S):

·        Lumbricus [L. lumbricus = earthworm] i.e, a 100 – 180-segmented earthworm commonly found in Europe and America, with a clitellum in 33 – 37 segments.

[Ref.: http://www.naturenorth.com/fall/ncrawler/Night_Crawlers_02.html]

·        Pheretima: [Gk. Pheretime = wife of the Gk. Cyrenaean King Battus III].:             

NOTE: No proper explanation could be found about the similarity between the Genus Pheretima and the queen’s name Pherertime except the following excerpts where the name ‘worms’ appears:

“As a postscript to these grisly events, Pheretima herself ended badly. Herodotus reports that during the return to Egypt, she contracted a disease which saw her body horribly waste away, consumed by worms before her very eyes”.[vide: https://www.encyclopedia.com ›]

An earthworm with about 100 – 120 segments and a clitellum surrounding 14 – 16 segments.