Holoscolex dossantosi Hernández-García, Rousseau & James, 2018

Hernández-García, Luis Manuel, Burgos-Guerrero, Jesús Enrique, Santos, Bianca Tamires Silva Dos, Rousseau, Guillaume Xavier & James, Samuel Wooster, 2018, Three new species of Holoscolex (Clitellata, Glossoscolecidae) from the Gurupi Biological Reserve, last forest remnant of the Belém Endemism Area, Eastern Amazon, Zootaxa 4496 (1), pp. 459-471 : 461-462

Holoscolex dossantosi Hernández-García, Rousseau & James , sp. nov.

( Figure 2 )

Holotype. MPEG.ANL 0 0 0 307 one adult, clitellate, amputee. Gurupi Biological Reserve , primary forest, Centro Novo do Maranhão, Maranhão, Brazil, 3°41'24.87"S 46°45'12.96"W, 188 masl. 26 March 2015, Hernández- García, L.M. & Rousseau G.X. colls.

Paratypes. MPEG.ANL 0 0 0 308 two adults, clitellate, amputee, same locality as holotype ; MPEG.ANL 0 0 0 309 two adults, clitellate, fragmented, Gurupi Biological Reserve , logged primary forest, Centro Novo do Maranhão, Maranhão, Brazil, 3°41'10.76"S 46°45'56.54"W, 158 masl. 28 March 2015, Hernández-García, L.M. & Rousseau G.X. colls.

Description. Dimensions: holotype 40 mm long and 2.5 mm wide at X, 2.7 mm at clitellum, 2.5 mm at XXX, 111 segments; paratypes 43–46 mm by 2.1–2.4 mm at X, 2.4–2.6 mm at clitellum and 2.2–2.3 mm at XXX, 114– 120 segments. Body cylindrical. Setae AB and CD begin on IV. Setae AB widely paired while those of CD are narrowly paired. Setal arrangement aa:ab:bc:cd:dd = 1.8:1.0:0.8:0.1:2.8 at XXX, dd <1/2 circumference throughout. Prostomium pro-epilobous. Ovipores microscopical on small ventral elevations, equatorial approximately at the level of setae A in XIV with distance of 0.75 mm between pores. Two pairs of spermathecal pores in 7/8 and 8/9 open in B line just over intersegmental semilunar grooves associate to circular papillae. Microscopical male pores in 20/21 inside the tubercula pubertatis; milk-white clitellum saddle to BC in XVI– XXIV. Tubercula pubertatis on XIX–XXII in B line and looking like two double bands on each side, a larger and a smaller one, the smaller one from XX–XXI and with some internal wrinkles like spiral bands. Genital markings as circular papillae in VIII and IX just on AB line. Setae with papillae similar to common setae. In segment VIII genital markings are in setal line C, in IX they are in setal line B. Other small and paired genital markings on A line and becoming more widely spaced from XV to XVIII ( Fig. 2A ). Genital markings also on segments XXIII–XXV on A line. Setae related to genital markings of straight shape in the apical region and 300 µm in length ( Fig. 2B ). Common setae of post-clitellar region sigmoidal and 85–90 µm in length ( Fig. 2C ). Nephropores small, just dorsal to setal line C, very small and smooth valves are visible on body wall.

Septa 6/7–9/10 equally thick and muscular, 10/11 thinly muscular, other septa membranous. Alimentary canal with large cylindrical gizzard in VI; esophagus with high chevron pattern lamellae in VII–IX, longitudinal lamellae in 9–10, intestinal origin in XIII, with a dorsal typhlosole from the beginning. Thyphlosole as disk-shaped, concave folds in XV–XXVII, then wavy laminar. Calciferous glands of composite-tubular type originating in XII, with ovoid form for glandular part and conic sac form for membranous part, extending to XVI; dorsal blood vessel connects to a blood vessel on lateral face of gland part. The membranous part is a calcium carbonate reservoir on medial face of gland, towards duct ( Fig. 2D ). Vesiculated holonephridia; post-clitellar nephridia consisting of a thin tube arranged in irregular loops and connected directly with the bladder compartment ( Fig. 2E ). Vascular system with ventral trunk, single dorsal trunk, lateral vessels in VII–IX, latero-esophageal hearts in X and XI. A thin supra-esophageal vessel was observed from segment X connected to latero-esophageal hearts; the thin vessel runs along dorsal side of intestine without supra-esophageal hearts.

One pair of ovaries in segment XIII, ovarian funnels in intersegment 13/14 just on septum and with duct running to body wall opening on A line. Spermathecae in VIII and IX and opening in B line at 7/8 and 8/9 just adjacent to genital marking glands. There is not distinction between ampulla and duct. The structure is an elongate thin-walled sac, slightly tapering towards the ectal pore ( Fig. 2F ). Two pairs of setal glands associated to the spermathecae at A line in segment IX. Male sexual system holandric, testes and seminal funnels free in X and XI; medial to hearts of X–XI, narrow tubes from testes connect to two pairs of lobulated seminal vesicles in XI–XII; seminal vesicles of XII penetrate septa and extend posteriorly along intestine to XIV–XV; vasa deferentia on body wall at B en route to enter body wall in 20/21 within tubercula pubertatis.

Etymology. The species is named in memory of Raimundo dos Santos Rodrigues, farmer and environmentalist, member of the Gurupi Biological Reserve Council, murdered August 25, 2015 by ranchers.

Remarks. Holoscolex dossantosi sp. nov. resembles Holoscolex caramuru Righi, 1975 and Holoscolex nemorosus tacoa Righi et al., 1978 by the presence of two pairs of spermathecae in VIII and IX, the presence of tubercula pubertatis and the beginning of clitellum on segment XVI. They are, however, separated by the following characters ( H. dossantosi sp. nov., vs H. nemorosus tacoa and H. caramuru ): i) length of tubercula pubertatis, XIX–XXII vs. XIX–XXI; ii) male pores in 20/21 vs. XX; iii) spermathecal pores in B vs. BC in H. nemorosus tacoa and B in H. caramuru . Moreover, H. dossantosi sp. nov. has distinctive genital markings, which are gradually more widely placed on segments XV–XVIII, and tubercula pubertatis looking like double bands. Furthermore, H. dossantosi sp. nov. has a distinctive setal arrangement; setae are widely paired ventrally and narrowly paired laterally.

Figures

FIGURE 2. Holoscolex dossantosi sp. nov. (holotype). A. Ventral view of clitellar region. B. Genital setae of right papilla on A line of XVIII. C. Common seta of right A line of XXX. D. Dorsal view of right calciferous gland. BV, blood vessel; G, glandular region; M, membranous region. E. Frontal view of right post-clitellar nephridium. np, nephropore; npt, nephrostome; V, nepridium vesicle; Bd, bladder. F. Dorsal view of right spermatheca of VIII.