Syngenodrilus lamuensis Smith & Green 1919

Jamieson, Barrie G. M. & Fragoso, Carlos, 2024, A monograph of the Oligochaete family Alluroididae, Zootaxa 5529 (3), pp. 401-435 : 432-433

Syngenodrilus lamuensis Smith & Green 1919

Syngenodrilus lamuensis Smith & Green 1919: 145 , Fig. 1–8 .

Syngenodrilus lamuensis Smith & Green. Gates 1945: 393 ; Pickford 1945: 397; Jamieson 1968: 85; 1971: 719.

Length 52 mm, width 4 mm, segments137. Clitellum annular 2/3 XI–XVI. A copulatory band extends from 11/12 to setal arc XIV and filling bc. Setae very small; aa: ab: bc: cd: dd =17: 1:17 0.9:92; dd =0.6 U, bc =1.0 aa; present in the clitellar region. Nephropores commencing at the anterior margin of IV; some midway between cd and the mid–dorsal line others in cd. Male pores at the anterior margin of XIII at about 3/5 bc. Prostate pores intrasegmental in XI, XII and XIII, slightly dorsal of setal line b, presumably paired. Female pores slightly anteriad and dorsal to setae b of XIV. Spermathecal pores two pairs immediately in front of intersegmental furrows 7/8 and 8/9, slightly ventral of setal lines c.

Septa 5/6–7/8 very strong. 8/9–12/13 very thin and imperfect. Strong gizzards in VIII and IX. Intestine commencing in XII or XIII, but oesophagus widened between it and the gizzard. No calciferous glands, intestine lacking typhlosole. Hearts in VI –XI (XII?), possibly absent from X. Nephridia paired; absent from I–III, XI and XII; with pyriform terminal dilatation. Testes and funnels paired in X and XI and enclosed in (unpaired?) testis–sacs containing hearts and nephridia. Seminal vesicles of the microdrile type, a pair extending backwards in the ovisacs to XX. Vasa deferentia lacking terminal atria. Three pairs of short tubular prostates, in XI, XII and XIII, opening separately from the male pores by very short ducts which are confined to the body wall. Penial and genital setae absent. Ovaries extensive in XIII; funnels broad and short on the anterior face of septum 13/14. Ovisacs extending posterior of XXII. Eggs yolky. Spermathecae two pairs, in VIII and IX, each with an irregular, simple tubular ampulla, ca 0.35 mm wide and somewhat longer than the duct which is 0.07–0.1 mm wide: lacking diverticula.

Remarks. Gates (1945) and Pickford (1945) rightly argued for exclusion of Syngenodrilus from the Moniligastridae, They recognized its affinity with the Alluroididae, Gates tentatively suggested inclusion in this family but Pickford advocated retaining a separate family Syngenodrilidae . Both authors noted that it differs from the Alluroidinae in possession of a well–developed, double oesophageal gizzard, in having simple Sparganophilus - like prostate glands which are not related to the male opening and in the absence of a moniligastrid–like atrium at the ectal end of the vas deferens.

Distribution. Kenya: Lamu (Habitat unknown).

Figures

FIGURE 1A. Hennigram (morphological phylogram) for all families of the opisthoporous oligochaetes constructed by nearestneighbour clustering. For details see Jamieson (1978). Redrawn.

FIGURE 2. A phylogenetic classification of the Clitellata. (From Jamieson 2006).

FIGURE 3. Brinkhurstia americanus (Brinkhurst 1964). Longitudinal section through the male terminalia. at.ch, terminal chamber of atrium; at.d, atrial duct; gl.sh, glandular sheath; m.sh, muscular sheath; o.v, ovary; pro, protractor muscle; p.s, penial seta; re, retractor muscle; sep, septum; v.d, vas deferens. From Jamieson (1968).

FIGURE 4. Alluroides brinkhursti brinkhursti Jamieson (1968). Longitudinal section of the holotype. Abbreviations: br, brain; bv, blood vessel; m, mouth; msh, muscular sheath of atrium; oe, oesophagus; oo, oocyte: os, ovisac; ph m, pharyngeal musculature; pr c, prostatic cells; sep, septum; sep gl, septal gland; sp p, spermathecal pore; s. ves, seminal vesicle; sp, spermatheca; sp f, sperm funnel; tes, testis; vd, vas deferens; v n, ventral nerve cord. Adapted from Jamieson (1968).

FIGURE 5. Alluroides brinkhursti brinkhursti Jamieson (1968). A. Transverse section (TS) of clitellum, showing single cell layer; the cells with conspicuous secretory granules and each with a basal nucleus. B. TS through the wall of the atrium, showing a group of atrial gland cells with ductule penetrating the muscular sheath of the atrium. C. Longitudinal section through the male pore, showing the ectal end of the atrium, which forms a penis with muscular sheath, ciliated epithelium and rope of spermatozoa in the lumen, forming in the ectal chamber a sperm mass. D. Alluroides pordagei. Oblique section through the atrial bulb, containing a large sperm mass, and the associated atrium. From Jamieson (2006).

FIGURE 6. Alluroides brinkhursti abyssinicus Jamieson (1968). Longitudinal section of holotype. Abbreviations: epi, epithelium of atrium; gl sh, glandular sheath of atrium; m, mouth; msh, muscular sheath of atrium; oe, oesophagus; oo, oocyte: ph m, pharyngeal musculature; s.ves, seminal vesicle; sp, spermatheca; vbv, ventral blood vessel; vd, vas deferens; v n, ventral nerve cord. Slightly modified from Jamieson (1968).

FIGURE 7. Alluroides lauzannei Ljungström, 1971. Detail of an atrium. Note the vas deferens entering the apex of the atrium via canaliculi. Relabelled from Lauzanne (1968).

FIGURE 8. Alluroides pordagei Beddard 1894. A. Longitudinal section of the anterior region of the body of Beddard’s paratype. B. Spermatheca. C. Longitudinal section of wall of atrium. D. Transverse section of atrium.Abbreviations: at, atrium; at ch, atrial chamber; br, brain; cil, cilia; ep, epidermis; epi, epithelium; gl duc, glandular ductule(s); gl sh, glandular sheath; int, intestine; lum, lumen; m, mouth; ph m, pharyngeal musculature; per, peritoneum; sep.gl, septal gland; sp, spermatheca; sperm, spermatozoa; sph, sphincter; sp epi, spermathecal epithelium; sp m sh, muscular sheath of spermatheca; v.d, vas deferens.. Slightly modified from Jamieson (1968).