Atatina arimikuriaka, Hernández-García & Rodríguez & James & Limeira-De-Oliveira & Rousseau, 2024

Hernández-García, Luis Manuel, Rodríguez, Giovanny Angiolillo, James, Samuel Wooster, Limeira-De-Oliveira, Francisco & Rousseau, Guillaume Xavier, 2024, Two new species of Atatina earthworm (Rhinodrilidae, Clitellata) from the Gurupi Biological Reserve, Maranhão, Brazil, Zootaxa 5514 (5), pp. 494-500 : 495-496

Atatina arimikuriaka , sp. nov. Hernández-García & James ( Figs 1A–G )

Holotype: LB00001 , adult, complete, collected under trunk, Logged Forest , Gurupi Biological Reserve, Centro Novo do Maranhão , Maranhão, Brazil, 3°37'21.09"S, 46°48'30.21"W, 135 masl, 25 March 2022, Hernández-García, L.M & Rousseau, G.X. colls.

Paratypes: LB00002 , adult, amputee, collected on trunk, LB00003 , adult, complete, collected in soil, same locality as holotype. LB00004 , two adults, completes, collected in litter, Old-growth Forest , Gurupi Biological Reserve , Centro Novo do Maranhão , Maranhão, Brazil, 3°37'12.54"S, 46°48'12.51"W, 139 masl, 24 March 2022, Hernández-García, L.M & Rousseau, G.X. colls. LB00005 , adult, amputee, collected in soil, Burned Forest , Gurupi Biological Reserve , Centro Novo do Maranhão , Maranhão, Brazil, 3°32'31.99"S, 46°47'43.93"W, 128 masl, 29 March 2022, Hernández-García, L.M & Rousseau, G.X. colls. LB00006 , adult, amputee, collected in soil, Logged Forest , Gurupi Biological Reserve, Centro Novo do Maranhão , Maranhão, Brazil, 3°37'16.21"S, 46°48'9.54"W, 133 masl, 24 March 2022, Hernández-García, L.M & Rousseau, G.X. colls .

Etymology: The species name comes from an adaptation of the Awa Guajá indigenous language, spoken by almost 600 people. These people were contacted 40 years ago and live in the indigenous territories Caru, Awa, Alto Turi-Açu and Arariboia in the state of Maranhão. They named this earthworm species “fat head” (jakyÞ mete'eÞnuhuÞa) “earthworm” (arimikuri).

Description. Dimensions: holotype 57 mm in length by 2.35 mm at X, 2.76 mm at clitellum, 2.52 mm at XXX, 219 segments; complete paratypes 46–68 mm in length by 1.8–2.83 mm at X, 2.0– 2.93 mm at clitellum and 1.90–2.7 mm at XXX, 218–302 segments.Body cylindrical, dorsally brown after fixed, light brown ventrally, mainly after clitellum. Setae ab and cd commence on II, closely paired type. Setal arrangement aa:ab:bc:cd:dd = 6.0:1.0:7.3:1.0:25.0 at XXX. Prostomium partially retracted, however, it can extend over more than one segment when stretched, approaching Righi's definition ( Righi & Araujo 2000) of tentacular prostomium ( Fig. 1A ). Clitellum annular in XIII–XXII for all individuals collected. Genital markings absent. Tubercula pubertatis as thin puberal furrows in XVI–XXI next to C line ( Fig. 1B ). Post-clitellar common setae slightly sigmoidal, four individuals with truncated setae (cut off at apical part) in XXX–XL and 112–143 μ m in length. Two complete extracted setae a measured 170 and 317 μm, smooth at the apical part ( Fig. 1C ). Intraclitellar genital setae at AB line, truncated, 200–300 μm in length; the unique complete seta obtained measured 312 μm, lacking ornamentation ( Fig. 1D ). Microscopical male and female pores not recognized externally. Three pairs of spermathecal pores are present just near the intersegmental lines 5/6–7/8, laterally in CD line. Nephropores visible from V in CD line.

Septa 6/7–8/9 absent, 9/10–14/15 membranous. Gizzard in segment VI, externally occupying four segments, highly muscular. Intestinal origin in XVI. Typhlosole started as thick simple folds at XVI that extends to LXVIII and occupy approximately 60% of the intestinal diameter. It gradually decreases in occupation and disappear after CLXXIX. Three pairs of intramural calciferous glands, lamellar structure, are present laterally in X–XII, as vertical folds of esophageal wall opening in the lumen, size depending on the esophagus development which is more dilated on XI ( Fig. 1E ). Holonephric, the nephrostome in postclitellar nephridia is connected to a tube (first loop), as long as the bladder. A second loop, same length, connect to the bladder ( Fig. 1F ). Blood vessels of VII aborted, two pairs are visible in VIII–IX connected to dorsal and ventral vessel. Two pairs of big lateroesophageal hearts, kidney shaped, in X–XI. Supra-esophageal vessel runs over the dorsal side of the intestine.

Ovaries in XIII. A pair of female funnels are in 13/14; female pores open in 14/ 15 in A line. Three pairs of spermathecae in V–VII; Seminal chambers absent, spermatheca duct measuring 274–301 μm wide and 240–790 μm in length, saccular ampulla measuring 350–475 μm wide and 746–820 μm in length, the pores of the spermathecae open at the posterior region of the segment ( Fig. 1G ). One pair of testicles and male funnels enclosed in testes sacs in XI. A pair of long seminal vesicles in XII extending laterally to XLIII. A pair of intraparietal and iridescent deferent ducts, go parallel through C line and open on 16/17 on the tubercula pubertatis line.

Remarks. As some important characters, like male pore and seminal chambers, for A. albida Bartz & Decaëns 2024 were insufficiently described we focus comparisons with others Atatina species. Atatina arimikuriaka sp. nov. is similar to A. puba Righi 1971 by the position of male pore. Major differences are in the type and extension of clitellum (annular in XIII–XXII vs saddle-shaped in XIV–XIII), number of spermathecae (three vs one), and by the number and position of calciferous glands (X–XII vs IX–XIII).

Figures

FIGURE 1. Atatina arimikuriaka sp. nov. A. Ventral view of first thirteen segments. B. Ventral view of clitellum region. C. Left common a seta of XXXVIII. D. Right genital a seta of XIX. E. Dorsal view in cross-section of the left calciferous glands of X–XII. F. Left post-clitellar nephridia of XXX. G. In situ dorsal view of right spermathecae of V–VII. amp: ampulla. bd: bladder. c: crop. d: duct. dv: dorsal blood vessel. Gz: gizzard. h: lateroesophageal heart. I: intestine. lam: lamella. lu: intestinal lumen. np: nephropore. pr: prostomium. sv: seminal vesicle. sp: spermathecal pores. TP: tubercula pubertatis.