Zapatadrilus aurelius Cervantes & Fragoso

Cervantes, Gabriela, Fragoso, Carlos, Monteros, Alejandro Espinosa De Los, Sánchez-Ramos, Gerardo, Lara-Villalón, Manuel, Yañez-Pacheco, Manuel De Jesús, Lázaro-Castellanos, Jesús Omar & James, Samuel W., 2016, New species of the earthworm genus Zapatadrilus (Clitellata, Acanthodrilidae) from northern Mexico, Zootaxa 4189 (2), pp. 311-326 : 313-315

Zapatadrilus aurelius Cervantes & Fragoso , sp. nov.

( Figures 1 , 4 A,D)

Localities and material. MEXICO, Tamaulipas: (1) Salto del Tigre , ejido El Olmo , Municipality of Güemez. Gallery forest. N 24 ° 0' 15.51", W 99 ° 20' 35.94", 307 m asl ( Fig. 5 ). September 19th, 2013. Collectors G. Cervantes, M. Lara-Villalón, O. Lázaro, G. Sánchez-Ramos & M.J. Yañez-Pacheco.

Holotype. One clitellate adult, IEOL4480. Complete specimen, last segments amputated to obtain DNA.

Paratypes. Two clitellate adults, IEOL4479, IEOL4481.

Description. External. Length 84–125 mm (mean= 108.5 mm, n=3; holotype 116.5 mm); postclitellar diameter 3.7–6.9 mm (mean=5, n=3; Holotype 6.9 mm). Segments 145–168 (mean=153, n=3; holotype =168). Colour white. Prostomium closed epilobous, reaching 1/3 of the first segment. Secondary annulation in 4–13; one postsetal in 4, one presetal and one postsetal in 5–13, behind clitellum two presetal and two postsetal. Setae eight per segment, visible from segment 4, very small and difficult to observe. A ring of yellow spots is present on each segment, giving the appearance of a greater number of setae in perichaetine arrangement. Setal formula (aa:ab:bc:cd:dd) in 10: 2.5:1.0:3.7:1.0:15; in 30: 5:1.0:6.2:1.7:20. Genital setae absent. Penial setae absent. Annular clitellum dorsally and ventrally in 14 –1/2 18, interrupted in 1/2 17 –1/2 18 in AB ( Fig. 1 A), color brown. Dorsal pores present all along the body, first pore in 11/12 but clearly visible from 13/14 (N = 3 ind.). Spermathecal pores paired in 8 and 9 in A, very close to 7/8 and 8/9, respectively, very small on papillae. Female pores in 14 mesial to A, within a papilla ( Fig. 1 A). Two pairs of prostatic pores in 18 and 20 in A, joined by square bracketshaped seminal grooves, which

run along A ( Fig. 1 A). Male pores in 19 in A. Setae ab absent in 18, 19 and 20. Genital male area in 18–20. Genital markings one in segment 17, ovoid, around setae AB; postclitellar transverse papillae of 22–23 ovoid -rectangular, reaching seta C (3 ind.), inside with another similar but smaller structure, covering 2/3 – 3/3 of 22 and 1/3–2/3 of 23 (2 ind.). Other genital markings (absent in holotype) in 8, 9, rectangular, those in 8 largest, covering 2/3–3/3 of segment, those in 9 covering 1/3–2/3 of segment; each marking extending beyond B (N=2 ind.).

Internal. Muscular, imbricated funnel-shaped septa in 5/6–9/10, joined by 2–4 dorsal and lateral connective tissue fibers. Septa of 10/11 and 11/12 slightly muscular, not funnel-shaped, and with many fibers (4–9 per side). From 12/13 and backwards septa thin. Two gizzards, in 5 and 6, largest in 6; both gizzards preceded by a thinwalled esophagus in the first third of 5 and 6. Esophageal lamellae present: dorso-laterally and small in 9, laterally and large in 10 and 11, small in 12, 16 and 17, and ventro-laterally and large in 14 and 15. Calciferous glands absent. Intestine beginning in 17/18 (3 ind.), dilated. Single dorsal vessel visible in 20–40. Incipient intestinal typhlosole laminar, a thin line from 32 to 52. Lateral typhlosoles absent. Intestinal caeca absent. Lateral hearts in 7– 9. Latero-esophageal hearts in 10–13. Two ventral vessels and two infra-latero-esophageal vessels in 9. Paired infra-esophageal vessels in 14 adhering to septum 14/15. A pair of ventral-parietal vessels in 15, 16 and 17. A pair of latero-parietal vessels in 14, 15 and 16. Plectonephridia present, over 50 micromeronephridia counted in segment 30, not arranged in rows. Septal meronephridia observed in 5–7. Dorsal tufts of meronephridia in 4.

Holandric. Testes in 10 and 11. Iridescent male funnels and shrub-shaped testes in 10 and 11, the anterior smaller. Two pairs of racemose seminal vesicles of similar size in 9 and 12 that join 9/10 and 11/12, respectively, in dorso-lateral position. Two pairs of tubulo-racemose prostates in 18 and 20, tongue-shaped, extending one segment behind. Muscular duct narrower and shorter than glandular part. Lumen very small but still visible ( Fig. 4 D) Ovaries one pair in 13, bush shaped, with ovules irregularly distributed. Two pairs of spermathecae with sessile diverticulum, in 7 and 8. Each spermatheca with single diverticulum with multiple chambers; ampulla longer than duct and diverticulum ( Fig. 1 B–D). Duct of both spermathecae traversing posterior septum (7/8 and 8/9) and reaching 8, and 9, respectively.

Etymology. The species is named after Aurelio Lázaro Cervantes, son of Gabriela Cervantes.

Remarks. Most similar to Zapatadrilus aurelius sp. nov. are Z. albidus , Z. redelli , Z. ticus , further the new species Z. huastecus sp. nov. and Z. montezumensis sp. nov. For a comparison with the new species, see the remarks below. The new species is separated from Z. albidus and Z. redelli by the penial setae (absent vs. present), beginning of intestine (17/18 vs. 16/17) and typhlosole (present vs. absent). Zapatadrilus aurelius sp. nov. is separated from Z. ticus by the body colour (white vs. orange), the first dorsal pore (11/12 vs. 13/14), penial setae (absent vs. present) and the beginning of the intestine (17/18 vs. 16/17). Further differences between Zapatadrilus aurelius sp. nov. and other species of the genus are presented in Table 1.

Figures

FIGURE 1. Zapatadrilus aurelius sp. nov. Holotype IEOL 4480. A. Anterior region of specimen, external ventral view. B – D. Right spermatheca from segment 8, dorsal view (B), lateral view (C), and ventral view (D). Am = Ampulla, Di = Diverticulum, Du = Duct, Gm = Genital marking, Gp = Genital papilla. Scale bar 1 mm.

FIGURE 4. Right prostate glands of segment 18 of the three new species. A – C. External appearance, dorsal view, photograph. D – G. Cross section, scanning electron micrographs. A, D. Zapatadrilus aurelius sp. nov. B, E. Zapatadrilus montezumensis sp. nov. C, F, G. Zapatadrilus huastecus sp. nov. In external appearance (A – C), the prostates of the three species are racemose, but internally (D – G), the cross sections reveal the presence of a single central duct; therefore the prostates are tubulo-racemose. The central duct is indicated by a red arrow. Scale bars = 100 µm (D, E), 50 µm (F), 10 µm (G).

FIGURE 5. Type locality of Zapatadrilus aurelius sp. nov. El Salto del Tigre, Güemez, Tamaulipas. Gallery forest. When sampling was realized (September 2013) the river was growing and some of the trees were flooded. (Colour images only in electronic version).