The evolutionnary changes in the nephridial system of pherettima kinberg 1867 oligochaeta megascolecidae

V N U J O U R N A L O F S C I E N C E , N a t Sci & T e c h , t.X V III, n ° l - 0 T H E E V O L U T IO N A R Y C H A N G E S IN T H E N E P H R ID IA L S Y S T E M O F P H E R E T IM A K IN B E R G , (O L I G O C H A E T A , M E G A S C O L E C I D A E ) T hai T ran B ai, Tran T h i T h an h B in h Faculty o f Biology, Hanoi University o f Pedagogy Bahl when doing the first research on the nephridial system of Pheretima posthuma, Ph hawayana, and Ph Corticus in 1919 had discovered three kinds of meronephridia: closed tufted meroncphridia flowing into oesophagus; open septal m eronephndia flowing into intestine and closed integumentary rneronephridia running outside through body-wall (Bahl 1947) These kinds of m eronephridia are also m entioned in Ph Hupeiensis (G rant 1955 quoted from Easton 1979) In 1979, when amending the taxonom y of Acoecata group (Pheretim a w ithout caeca), Easton added d ata about nephridial system of Ph sentanansis, Ph neoguinensis, Ph taprobanae, Ph elongata, Ph Stelleli and another species, ill Pheretim a group, Pleinogaster horsti Easton added in B ahl’s nephredial system diagram some variation of each kind of m eronephridia in A coecata group: - Pharyngeal m eronephridia may have either pairs or over pairs: pairs ill Ph Naoguinensis (from segment IV to VIII); pairs in Ph Sentanensis and Pleionogaster horsti (from segment IV to IX) Three pairs of anterior pharyngeal m eronephridia flow into pharynx; posterior pairs run outside through body wall - The first segment containing integum entary m eronephridia can change depending on each species, from segment II to X To some species (Ph sentanensis, Ph taprobanae) integumentary meronephridia of some last segments flow into a pair of sem iannual lateral sinuses - The location of septal m eronephridia is both on anterior and posterior septal faces (Ph sv.ntanensis, Ph neoquinensis) or only oil anterior faces for startin g septum changes according to species In Ph Elongata and Ph Stelleri this kind of m eronephridia runs outside through body wall Thus, basing on the common diagram of the nephridial system of Pheretim a Bahl had proposed the specific expression about its diversified forms and quantity dem and to calculate many species of this genus and species from different ecosystems in order to imagine the general evolution of this complex organ system In this article, the features of nephridium observed are: - Septal meronephridia: the attached location of m eronephridia; the location of m eronephridia funnels (on anterior or posterior septal faces); the first septum to carry; the number of septal meronephridia attached on anterior and posterior septal faces; the change ill the number of septal nephridia along body, the num ber of supraintestinal excretory ducts and measurement of m eronephredial funnels - Integumentary rneronephridia: the first septum to contain and the change of their number in the successive segments T y p e se t by T h a i T n B a i , T n T h i T h a n h B i n h - Pharyngeal meronephridia: the number of pairs of pharyngeal meronephridia; location of first pair and ways of fluid flowing into pharynx All the observations are carried out under the binocular magnifier with the enlarge­ ment from to 56 times The measurement of meronephridial funnels is the average of 10 X tim es, measured on individuals in each species under the m icroscope based on ocular and objective micrometers in order to count up the real measurement Supraintestinal excretory ducts and pouring location of m eronephridia are determ ined on the serial transversal and longitudinal slices through the middle section (segments XXX - XXXII), the head section and tail section of individuals in each species The slice’s thickness is 20/im, colored by hematoxylin - eosin The observations are carried out on 71 species Among them, there are species in Acoecata group 62 species in Coecata (Pheretim a with caecum), consist of 46 species with simple caecum (including species in Planapheretim a), species with lobed caecum and species with manicate or plum ate caecum The species observed and the number of specimen observed in each species are shown in table The quantitative data are processed by statistics and introduced by M ± m (average ± change of average) T H E RESULT OF RESEARCH I T h e change o f kinds o f m eron ephridia in P h eretim a Table shows the change of kinds of meronephridia in Pheretim a The degree of changes varies according to each kind of meronephridia - Septal meronephridia: About attached location, septal m eronephridia can attach either on the body wall or on septum at different height from the foot of septa to a position near intestine M eronephridia can attach on both anterior and posterior septal faces with larger number on posterior or on anterior septal faces As to Ph Dacnomonntis, meronephridia only have on posterior septal faces Septal meronephridial funnels are both on anterior and posterior or only on anterior septal faces The diam eter of nephridial funnels is rather stable in each species, but variable among species M eronephridia begins to have from different septum depending on species, largely from septum 15/16 but it can begin earlier (from septum 14/15) or later, even very late (in Ph Grandisetosa and Ph Colonensis beginning from septum 70/71) There can be two or one supraintestinal excretory ducts (figure A, B) We don’t find septal m eronephridia running outside through body wall as E aston’s statem ent about Acoecata species (Easton, 1979) Considering the change in the number of septal meronephridial along body, the number of septal meronephridia rises to the maximum in certain septa (depending on species, about from septa 30/31 to 70/71) and then falls to the end of body (figure 2) However, in some cases, it reduces from the head to the end of body (Ph morrisi, Ph plantoporophorata, Ph samphoni, Ph thaibinhensis, Ph Uncipenifera from C oecata and Ph tani, Ph Taprobanae from Acoecata) Tablel: Features of the nephridial system s o f some species in Pheretima K inberg, 1867 (C: specimen have clitellum; A: specim en h a v e n ’t clitellum; S: on septa; b.w: on body-wall; or faces, a.p.f: on both anterior and posterior faces; : nu m ber of septal nephridia on anterior more or equal on posterior septal faces; r rising; f.: falling; S4: on anterior septa 4/5; Ph5: on phryngeal in 5th segment; res.: respectively; up.d: upside- down ) m ero n e p h rid ia Number of specimen observed Funnel The first Septal nephridia’s nephridia's septa having septal location location nephridia P haryn Integum entary m cronephridia Septal Comparative Longitudinal number of changes in the successive septal septa nephridia on anterior and posterior septal faces Diameter of funnels (M ± m) |im The first Tendency of Number of segment have num bers’ supra change in intestinal successive excretory segments ducts after XXX m ero n ep Number of pair The sepia h phary neph (10) ill) (12) (13) (14 III f S4 ! HI f S4 III f S4 V r S4 41 ± III f S4 r - f 49 ± 1 III f S4 > r - f 67 ± -) III f S4 15/16 < r - f 31 ± n II f S4 a.f 14/15 > r -f 43 ± III f S s a.f 14/15 > f 66 ± III f S 30C s a.f 14/15 < r -f 38 ± 1 III r S nensis Thai el Tran, 3C s a.f 15/16 > r -f 64 ± 1 III r S a, 1891) 3C s s s s a.f 14/15 > r -f 61 ± (9) (3) (4) (5) (6) (7) (8) , 1888) 3C s a.f 15/16 n r - f 1984 3C s a.f 15/16 < f - r - f 49 ± I l Huynh, 1993 2C s a.f 15/16 < r - f s, 1936 3C s a.f 14/15 < r - f 38 ± eiisis Do ct Tran 1994 3C s a.f 14/15 > r -f et Tran, 1986 3C s a.f 14/15 > 3C s a.f 15/16 3C b.w a.p.f Thai, 1982 2C s crg, 1867 2C , 1892 2) cata lu m ate caecum 1982 t Samphon 1988 caecum s Thai 1984 1C 1872 3C rrier, 1872) 3C a.f 17/18 r -f 35 ± a.p.f 15/16 > r - f 86 ± a.p.f 15/16 > r - f 98 ±1 III f S III f S III f S III f S (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (1 35 3C s a.f 15/16 < r -f 53 ± 1 X f S ơìa Thai, 1984 3C s a.p.f 18/19 > 37 ± I IV f S ana Thai, 1984 3C s a.p.f 16/17 < r - f 52 ± V f S a Thai cl Nguyen, 1993 IV f S e caecum 3C s a.f 16/17 > r - f 43 ± hai, 1984 3C s a.f 16/17 > r - f 64 ± 1 III f S osa Rosa, 1896 3C s a.f 16/17 < r -f 66 ± I III f S , 1946 3C s a.f 15/16 < r - f 80 ± III f S 1872) III f S V f S III r S III r S 3C s a.f 15/16 < r - f 25 ± 984 3C s a.f 16/17 < r -f 50 ± I 84 3C s a.f 20/21 < r -f 42 ± ube, 1879 3C s a.f 15/16 < r - f 32 ± , 1889 3C s a.f 15/16 > r - f 35 ± 1 V f S o et Huynh, 1992 3C s a.f 15/16 > r - f 72 ± 1 III r S4 et Huynh, 1992 3C s a.f 14/15 only on posterior r - f 42 ± 1 in f S4 o ct Tran, 1994 in t S4 HI f S4 III f S4 III f S4 III f S4 III f S4 in f S4 3C s • a.f 15/16 > r -f 60 ± hai, 1994 3C s a.f 26/27 < r - f 43 ± osa, 1890) 3C s a.f 15/16 > r - f 39 ± , 1984 3C s a.f 26/27 < r - f 37 ± 3C s a.f 14/15 > r - f 38 ± J ] 1890) 2C s a.f 15/16 > r - f 49 ± 1 et Samphon, 1989 3C s a.f 14/15 < r - f 67 ± I 1C+IA s a.f 15/16 < r - f 3C s a.f 15/16 < r - f 38 3C s a.f 15/16 > r - f theca Chen, 1938 3C s a.f 14/15 > aia Thai el Tran 1986 3C s a.p.f 15/16 et Samphon, 1988 3C s a.p.f el Sam phon, 198K 2C s 1994 1C s Thai, 1984 nson, 1931 38 ± 1 III f S4 40 ± III f S4 42 ± 1 III f S4 r - f 33 ± I III f S4 < r -f 49 ± III r S4 15/16 > r - f 25 ± IV f S4 a.p.f 14/15 57 ± 1 III f S4 15/16 < r - f a.f r - f 32 ± III f S4 , 1867) 3C s a.p.f 15/16 > r -f 36 ± III f S4 hai, 1984 1C s a.p.f 15/16 > r -f 31 ± , III f S4 et Samphon 1988 3C b.w a.p.f 16/17 > r -f 45 ± 1 II f S4 I 2) (3) (4) (5) (6) (7) (8) (9) (10) < 10 (12) (13) (14 et Samphon, 1989 1C b.w a.p.f 17/18 r - f 41 ± *) III f S5 3C b.w a.p.f 15/16 > r - f 48 ± 1 III f S4 3C b.w a.p.f 15/16 < r - f 50 ± III f S4 l Samphon, 1988 3C s a.f 15/16 > f 35 ± 1 II r S4 i et Samphon 1988 3C b.w a.p.f 15/16 > f 44 ± II r S4 ai, 1984 3C s a.p.f 15/16 > f 38 ± 1 II f S4 h 1895 3C s a.p.f 15/16 > r - f 34 ± II f S4 ant, 1869) 42C+8A s a.f 14/15 > r - f 37 ± 1 III r S4 nh 1998 3C b.w a.p.f 15/16 > r - f 42 ± ! II f S4 875 3C b.w a.p.f 15/16 > r - f 59 ± II r S4 3C s a.f 14/15 < r - f 44 ± III f S5 3C s a.f 14/15 < r - f 50 ± III f S3 1946 3C s a.f 14/15 > r - f 54 ± III f S4 1946 1C b.w a.p.f 14/15 > r - f 48 ± I III f S3 2C s a.f 14/15 < r - f 47 ± Ọ IV f S4 1C+1A s a.f 15/16 < f 43 ± IV f S4 ham, 1996 2C s a.p.f 14/15 > r - f 72 ± III r S4 ai, 1996 2A s a.f 70/71 < r - f VIII f S5 1996 3C s a.f 70/71 < r - f VIII f S5 Thai et Nguyen, 1C s a.f 15/16 > r - f 52 ± ? VII f S4 5C s a.f 15/16 < f 55 ± VII f S4 , 1996 2C s a.f 15/16 < r - f 42 ± IV r S r, 1872) I8C+12A b.w a.p.f 15/16 > r - f 43± 1 III r Ph et Samphon, 1988 pecies group h eretim a ta Thai, 1982 97 ecata 1996 ddard, 1892) 12 T h a i Tran B a i , T ran T h ỉ T h a n h B i n h Fig - Supraintestinal excretory ducts (1) and integum entary m eronephridia (2) o f Pheretima A - P heretim a p va mim gxetiensis; B- P h.lem brica; C- Ph kravicapitata (A ,B- transversal slices through 30th segment; C- sauital slice through the caudal segments) Ph.posthuma Ph.juliani h hupeiensis h.fluvialoides ghi chu ã -2 (-*