Pleionogaster valida, James, 2004

James, Samuel W., 2004, New Species Of Amynthas, Pheretima And Pleionogaster (Clitellata: Megascolecidae) Of The Mt. Kitanglad Range, Mindanao Island, Philippines, Raffles Bulletin of Zoology 52 (2), pp. 289-313 : 309-310

Pleionogaster valida , new species

( Figs. 4C, D )

Material examined. – Holotypes – adult ( NMA 003990 ), Philippines, Mindanao Island, Bukidnon Province, Mt. Kitanglad Range , 8 9' N, 124 45' E, 1800 m. elevation, coll. D. Balete, no date .

Others – ( KUNHM 002147 ) Philippines, Mindanao Island, Bukidnon Province, Mt. Kitanglad Range , 8 10.5' N, 124 51' E, 1900 m. elevation, coll. L. Heaney, 22 Mar.1993; 1 adult , 1 late juvenile ( FMNH 011068 ), Philippines, Mindanao Island, Bukidnon Province, Mt. Kitanglad Range , 8 10.5' N, 124 51' E, 1900 m. elevation, coll. L. Heaney, 22 Mar.1993; 1 adult ( NMA 003991 ) Philippines, Mindanao Island, Bukidnon Province, Mt. Kitanglad Range , 8 10.5' N, 124 51' E, 1900 m. elevation, coll. D. Balete , no date.

Etymology. – The species name valida means strong, robust or durable, and was chosen for the sturdy construction of this relatively large species.

Description. – Unpigmented, body 160-260 mm x 6.2-9.0 mm (vii), 6.0-9.5 (xv), 5.3-8.0 mm (xxv); 223-286 segments; body cylindrical in cross-section. segment x biannulate, xixiii triannulate, in postclitellar segments posterior annulus divided again to make segments quadrannulate. First dorsal pore 12/13 (4), 13/14 (1); spermathecal pores paired in 7/8, 8/9, 0.16 circumference apart, female pores closely paired in xiv, male pores paired in xviii, 0.15 circumference apart in 9 th setal line (3), 10 th line (1), 7 th line (1); 8-14 setae between male pores. Setae regularly distributed around segmental equators; estimated at 192-235 setae on vii, 106-135 setae on xxv; in vii no dorsal gap, in xx ZZ: YZ = 1.3-2.1, no ventral gaps. Clitellum annular xiv-2/3xvii; genital markings paired on 17/18 (4, including syntypes), anterior portion of xviii (1), paired anterior to and surrounding male pores, paired 18/19, broad single genital marking 19/20-2/3 xx (3), shorter unpaired genital markings anterior 2/3 of xxi, sometimes xxii ( Fig. 4C ). Body wall deeply folded inward over segments xviii, xix; fold slightly wider than separation of male pores. Nephridiopores visible on trailing edge of clitellum in xvii, as gaps in setal rings of postclitellar segments, apparently 10 pores per segment.

Septa 5/6-10/11 thick, muscular, 11/12 thinner, remainder thin. Weak gizzard in viii with typical iridescent outer wall but flaccid, esophagus heavily vascularized, with low vertical folds xi-xvi, intestinal origin xix, no caeca; thick annular intestinal gizzards xxvii-xxx (4, including syntypes), xxvi, xxviii-xxix (1); intestinal constriction 46/47-xlvii; typhlosole xlix-lxxv, lxxx, xcv, simple fold with lateral processes, 0.1- 0.15 lumen diameter.

Hearts x-xiii esophageal, commissural vessels v-ix lateral. Supra-esophageal vessel x-xvii, efferent parieto-esophageal vessels from body wall of xiv-xviii to ventral esophagus in xiv, extra-esophageal vessel seen from vi to xvii, where it enters gut wall. Longitudinal blood vessel slightly below mid lateral on body wall of anterior intestinal segments.

Nephridia present as peptonephridia on anterior face of 5/6, micronephridia preseptal vi-ix, on body wall thereafter; from xix posteriorly ten micronephridia per segment in regular ranks plus 2 meganephridia per segment, meganephridia connected to ureters flanking dorsal vessel.

Ovaries and funnels free in xiii, spermathecae paired in viii, ix without nephridia on ducts; each spermatheca with elongate ampulla bearing apical knob, ampulla not sharply demarked from duct; simple sac-shaped diverticulum joins duct near body wall ( Fig. 4D ). Male sexual system holandric, testes and funnels enclosed in annular sacs in x, xi, these sacs encompass hearts, seminal vesicles of xi; seminal vesicles xi, xii small, acinous; vasa deferentia extremely small, travel up prostatic ducts to join ental end of prostatic ducts; each prostate a single racemose mass, occupying xviii; with stout muscular duct; copulatory bursae lacking.

Remarks. – Pleionogaster valida is distinguished from Pl. horsti by its greater size, completely different arrangement of genital markings (no longitudinal row of midventral markings), closer spacing of male and spermathecal pores, different location of the intestinal gizzards, smaller number of micronephridia (10 vs.14 per segment in Pl. horsti ) and probably many other characters not recorded in previous publications on the genus. Differences from Pl. samariensis are greater number of micronephridia, greater number of intestinal gizzards, much larger body size, greater number of setae, and very different pattern of genital markings. Compared to Pl. jagori , Pl. valida has fewer micronephridia, more setae per segment, a similar body size, but different distribution, number and shape of genital markings.

In Easton (1979) and Michaelsen (1900) no mention is made of important nephridial characters, the different regions of the intestine, the unusually posterior appearance of the typhlosole, the longitudinal blood vessels on the body wall of intestinal segments, or the unusually long supra-esophageal blood vessel. These may be of intrageneric importance in distinguishing species, and important to higher-level systematics.

Figures

Fig.4. Spermathecae, and ventral views showing spermathecal pores, female pores, and male pores of Amynthas heaneyi (A,B), Pleionogaster valida (C, D), and Pleionogaster kitangladensis (E, F). Symbols: fp, female pore(s); mp, male pores; sp, spermathecal pores.