Zapatadrilus huastecus 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 : 315-317

Zapatadrilus huastecus Cervantes & Fragoso , sp nov.

( Figures 2 , 4 C,F,G)

Localities and material. MEXICO, Tamaulipas: (1) Old highway Victoria-Jaumave two kilometers after the Balcony of Montezuma , Protected Natural Area " Altas Cumbres ". Municipality of Ciudad Victoria. Oak forest stony with little soil. N 23 ° 36' 2.28'', W 99 ° 12' 53.75'', 1341 m asl. ( Fig. 6 A,B). September 18th, 2013. Collectors G. Cervantes and O. Lázaro.

Holotype. One clitellate adult, IEOL4490. Complete specimens, last segments amputated to obtain DNA.

Paratype. One clitellate adult, IEOL4489. Complete specimens, last segments amputated to obtain DNA.

Additional material. One incomplete clitellate adult, divided in two fragments, IEOL4492. Another incomplete clitellate adult, divided in two fragments and damaged during sampling, IEOL4493.

Description. External. Length 144–172 mm (mean= 158.3 mm, n= 3; holotype 172 mm); postclitellar width 5.9–7.2 mm (mean= 6.5, n= 4; holotype 6.5 mm). Segments 180–197 (mean=190.66, n=3; holotype 197). Colour white. Prostomium closed epilobous, covering half of 1st segment. Secondary annulation: one postsetal in 4–9, one presetal and one postsetal in 10–12; one presetal and two postsetal in 13. Setae eight per segment, visible from segment 2, closely paired. Setal formula in anterior region (aa:ab:bc:cd:dd) in 10: 2.4:1.0:4.0:1.1:16.0; in 30: 3.8:1.0:4.5:1.5:20.0. Genital and penial setae absent. Annular clitellum vermilion red dorsally in 1/2 13 –18 (3 ind.), ventrally in 1/2 13 –1/2 17 interrupted in AA region of 17 by the male genital area ( Fig 2 A). Dorsal pores present all along the body, first pore in 13/14. Spermathecal pores paired in 8 and 9, in AB, very close to 7/8 and 8/9, respectively ( Fig. 2 A). Female pores in 14, presetal and slightly median to A, almost mesial, within an ovoid papilla extending AB ( Fig. 2 A). Two pairs of prostatic pores in 18 and 20, very close to 18/19 and 20/21, respectively, just at the base of setae b and joined by square bracket-shaped seminal grooves, which run along B. Male pores in 19 near 19/20. Genital male area square-shaped in 1/2 17 –20. Genital markings unpaired midventrals in 7, 8 and 9, shape rectangular, extending beyond B (present in two specimens, absent in the other two specimens). Genital marking unpaired in 22–23 (present in 3 specimens, absent in the other one), mid-ventral, ovoid-rectangular, extending beyond B. A tiny ovoid-rectangular papilla in 21 (present in one specimen, absent in the other three). Holotype with three rectangular swellings in 7, 8 and 9, extending beyond B, and ovoidrectangular genital papilla in 22–23, extending beyond B ( Fig. 2 A).

Internal. Septa in 5/6–8/9 thick, muscular and funnel shaped; septa in 9/10 and 10/11 thin and membranous. Two gizzards, in 5 and 6; the latter is the largest; both gizzards are preceded by a thin-walled esophagus. Mesentery covering the esophagus of segments 7 and 8. Lateral and dorsal lamellae large in 11–13, small in 9 and 10. Coagulated blood in the body cavity in 10 and 11. Calciferous glands absent. Intestine beginning in 17/18. Intestinal typhlosole simple, a thin line from 32 to 52. Lateral typhlosoles absent. Intestinal caeca absent, intestine in 18–32 with a rough to pebbly appearance. Single dorsal vessel visible throughout. Supra-esophageal vessel visible in 10–12. Lateral hearts in 6–9. Latero-esophageal hearts in 10–12. Ventral vessel present. Plectonephridia present, over 50 per segment (observed in segment 30).

Holandric. Testes in 10 and 11, attached to iridescent male funnels by coaugulum, the latter are the largest. Two pairs of racemose seminal vesicles of similar size in 9 and 12. Two pairs of tubulo-racemose prostates of similar size in 18 and 20, tongue-shaped; muscular duct narrower and shorter than glandular part; central duct present, although very small and difficult to observe ( Fig. 4 C, F, G). Retractor muscles in 17–22. Male ducts intraparietal. Ovaries one pair in 13, arbuscular. Two pairs of spermathecae with sessile diverticulum, in 7 and 8, opening to spermathecal pores in 8 (the anterior ones) and 9 (the posterior ones). Holotype with the four spermathecae not symmetrically placed; the anterior in segment 7 (right) and 6 (left), the posterior in 8 (right) and 9 (left); openings to spermathecal pores in 8 (the anterior ones) and 9 (the posterior ones). A short duct continues to an ovoidal or pear-shaped ampulla, which in some cases is considerably elongated. Each spermatheca with a single sessile diverticulum with multiple chambers ( Fig. 2 B–E).

Etymology. The name huastecus refers to "huasteco", the gentilic adjective of the people from the Huasteca region.

Remarks. Most similar to Zapatadrilus huastecus sp. nov. is Z. aurelius sp. nov. The two species are separated by body size (144–172 vs. 84–125 mm), the first dorsal pore (13/14 vs. 11/12) and last latero-esophageal heart (12 vs. 13). Differences between Z. huastecus sp. nov. and other species of the genus are presented in Table 1.

Figures

FIGURE 2. Zapatadrilus huastecus sp. nov. Holotype EOL 4490. A. Anterior region of specimen, external ventral view. B, C. Right spermatheca from segment 7: dorsal view (B) and ventral view (C). D – E. Right spermatheca from segment 8: dorsal view (D) and ventral view (E). 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 6. Sites of distribution of Zapatadrilus huastecus sp. nov. and Zapatadrilus montezumensis sp. nov. A. Sierra Altas Cumbres, Tamaulipas, within the biogeographical region of Sierra Madre Oriental. B. Oak forest, type locality of Z. huastecus. C. Cloud forest, type locality of Z. montezumensis. (Colour images only in electronic version).