Diplomoela browni James & Bartz, 2023

James, Samuel W., Bartz, Marie L. C. & Brown, George G., 2023, New Ocnerodrilidae genera, species and records from Brazil (Annelida: Crassiclitellata), Zootaxa 5255 (1), pp. 235-269 : 264-266

Diplomoela browni James & Bartz sp. nov. ( Fig. 17 a-f)

Holotype. BRBA0010 , one adult, Pau Brazil Ecological Station ( ESPAB-CEPLAC), Porto Seguro , Bahia state, Brazil. S16.38596 W39.17433, 113 m asl., in surface soil and litter of primary forest; 14 November 2014, M.L.C. Bartz, H. Nadolny, E. da Silva and G.G. Brown, colls.

Paratype. none

Etymology. The species is named for George G. Brown in honor of his seminal role in increasing the study of earthworms in Brazil.

Description. Dimensions> 510 mm by 9 mm at segment x, 10 mm at clitellum, 10 mm at xxx, body cylindrical, segments>1020. A photo of the complete specimen upon collection can be seen in Silva et al. (2023). Setae closely paired anteriorly; AB setae commence in ix, CD in xi, setal formula AA:AB:BC:CD = 7:1:3.5:0.4 at xii, AA:AB:BC: CD = 5.5:1:3:1 at xxx; AA:AB:BC:CD = 3.5:1:2:1.5 at cxx; DD> ½ circumference. Prostomium broad epilobous open; segments lacking secondary annulations. Segments vi-x about 4.5 mm long, at xxx segments 1.7 mm long, and mid body 0.9 mm long. Unpigmented, incipient dorsal pores not open in 14/15, also incipient in 20/21 and posteriorly, spermathecal pores intrasegmental on low white papillae about AB distance above B in viii, ix in AB, 0.5 mm behind 7/8/9 ( Fig. 17d ). Ovipores in xiv in AB almost between those setae; male field acanthodriline, and between seminal grooves deeply depressed ( Fig. 17e ); prostatic pores in AB line, equatorial in xvii, xix prominent openings within broadly conical papillae; no copulatory chambers as the prostatic ducts are very small tubules within the muscular mass of the papillae; male pores in xviii in seminal grooves ( Fig. 17e ). Setae AB in xvii - xix absent. Clitellum on xv-xx; no genital markings ( Fig. 17e ).

Septa 3/4/5 muscular but transparent, 5/6-8/9 very thickly muscular, decreasing thereafter ( Fig. 17a ). Septa 8/9/10 posteriorly displaced with segment ix occupying 18 mm length internally, septa 10/11/12 attached to posterior face of 9/10 rather than to body wall; septa 12/13/14/15 very closely spaced, such that 14/15 placed at location of intersegmental furrow 14/15. Alimentary canal with large pharynx ( Fig. 17a ) and thick well-developed gizzards in viii, ix ( Fig. 17a, b ); esophagus valvular in xiii, intestinal origin in xiv; no typhlosole. Calciferous glands ovate, paired in ix, no central lumen, parallel small tubules converging near duct; glands with blood vessel from anterior end to extra-esophageal vessel, two large blood vessels from posterior end of gland, one to supra-esophageal vessel the other not traced. Gland attachment dorso-lateral face of esophagus, after the end of the gizzard in ix. Meronephric, first nephridia in segment vi, all apparently astomate. Nephridia of segments vi-viii on anterior faces of septa and within AB on body wall, from ix posteriorly scattered on body wall from AB level to mid-dorsal. One or two nephridia per block of longitudinal body wall musculature, numbers per segment from 60 to 74 in the region of segments xxx-lx ( Fig. 17f ); ventral nephridia larger, more elongate. Small tubules from nephridia converging on body wall, but no apparent common collecting duct; nephropores not seen.

Vascular system with ventral trunk, dorsal trunk, lateral vessels in iv-ix, latero-esophageal hearts x-xi. Supraesophageal vessel ix-xii. Dorsal trunk double vi-xii, perforate xiii; single elsewhere.

Elongate fan-shaped ovaries, funnels free in xiii; paired large adiverticulate spermathecae in viii, ix, duct muscular ectal bulb at body wall; ampulla tongue-shaped ( Fig. 17c ).

Male sexual system proandric, testes and funnels enclosed by septa 9/10/ 11 in x; vas deferens not seen; seminal vesicles acinous in xi, enclosed by fused septa 10/11/12 ( Fig. 17a ). Tubular prostates coiled under intestine within xv-xxx. Prostatic ducts long, muscular, without terminal muscular bulbs or copulatory pouches. Numerous large transverse muscle bands within xv-xx. Small diffuse glandular bodies in xi near 11/12 junction with body wall; glands with small pores in AB between equator of xi and furrow 11/12.

Remarks. This remarkable species is among the largest neotropical Ocnerodrilidae and its genus is the only one in the family with meronephridia. We were unable to obtain a DNA barcode for D. browni sp. nov. There is a second species as briefly described below.

Figures

FIGURE 17. Diplomoela browni sp. nov. D. Spermathecal pores (sp); E. Male genital field with male pore (mp) and prostate pore (pp); F. Meronephridia on internal body wall.