Arrenurus (Megaluracarus) maya, Ramírez-Sánchez, Marcia M. & Rivas, Gerardo, 2013

Ramírez-Sánchez, Marcia M. & Rivas, Gerardo, 2013, New species of subgenus Megaluracarus (Acari: Hydrachnidiae: Arrenuridae: Arrenurus) from Mexico, Zootaxa 3718 (4), pp. 317-330 : 326-328

Arrenurus (Megaluracarus) maya sp. nov.

( FIGURES 1 C, 2C, 3C, 4E–F, 19–25)

Type material. Holotype male from Chac-Ha cenote, 3.5 km northeast of Calotmul, Yucatan, 23 masl, 21º04’40” N 88º08’27” W, 9 July 2007, coll. G. Rivas et al. Paratypes: One female, two males (CNAC007182), same data as holotype. Other material: Three females, same data as holotype. Four males, Chamacos pond, El Edén ecological reserve, Quintana Roo, 50 masl, 21º12’01” N 87º11’42” W, 7 July 2007, coll. G. Rivas et al.

Diagnosis. Idiosoma sturdy; anterior margin smooth except by a frontal protuberance were the eyes are situated; cauda long and wider at its tip than at its base; setose acetabular plates ( Fig. 1 C, 19). P-II medial bears three long setae ( Fig. 21 ). Idiosoma and appendages are moderately intense greenish blue, with some yellowish areas in the dorsum, especially over the eyes, postocularia, and glandularia.

Description. MALE: Idiosoma 977 (1029–1050) long and 630 (662) wide; anterior idiosoma margin smooth with a frontal protuberance were the eyes are situated. Greatest width of dorsal shield 431 (452–462); dorsal shield length with cauda included 725 (735–819); non-caudal portion bearing the postocularia which are situated anterior to the D2 setae, these are particularly far from their corresponding glands; D2 and D3 glands very close to each other and both pairs located just on the widest portion of dorsal shield; D3 glands and setae distant from each other, with D3 setae lying far medially; D1 located anterior to the widest portion of the idiosoma ( Fig. 19 ). Cauda 389 (420) long, gradually broadened towards the posterior end when viewed dorsally; proximal width of cauda 210 (242–252), distal width of cauda 363 (389–399); posterior margin of cauda irregular with laterally directed lobes ( Fig. 1 C, 19); cauda lacks humps or protuberances in lateral view (Fig. 2C, 20). First and second pairs of coxae with sharply projecting anterior corners that extend slightly beyond anterior margin of idiosoma ( Fig. 3 C); second and third pairs of coxae separated by three rows of body pores; medial separation between third pair of coxae wider than between fourth; postero-medial corners of fourth coxae form an acute angle, distinct concavity in posterior margins of fourth coxae as a result of marked bulges over each epimeroglandularia (E4). Acetabular plates wing shaped with numerous long setae around their margins, these setae visible both in dorsal and lateral view ( Fig. 19, 20 ). Dorsal lengths of palpal segments ( Fig. 21 ): P-I 34 (28–30); P-II 68 (63–69); P-III 34 (30–38); P-IV 70 (70–73); P-V 40 (38–43); medial surface of P-II bears three long thickened setae; P-IV distoventral portion angular, but tip slightly rounded and with a relatively short antagonistic seta, 17 in length. Dorsal lengths of distal segments of first leg ( Fig. 22 ): I-Leg-4 133 (130–138); I-Leg-5 150 (145–150); I-Leg-6 250 (250). Dorsal lengths of distal segments of fourth leg ( Fig. 23 ): IV-Leg-4 200 (188–208), 230 (218–240) to tip of distal extension; IV- Leg-5 175 (175–188); IV-Leg-6 175 (170–200); IV-Leg-4 distal process bears four short flexible swimming setae; IV-Leg-3–5 bear both stiff and flexible swimming setae. Dorsal surface of IV-Leg-5 with three long spine-like setae placed in a zigzag pattern.

FEMALE: Idiosoma 919 long, 835 wide; anterior margin with a frontal protuberance where the eyes are situated; posterior margin with two medial and two lateral bumps ( Fig. 4 E); dorsal shield 620 long, 525 wide, bears the post-ocularia and three pairs of glandularia ( Fig. 24 ). Acetabular plate region 504 wide; acetabular plates laterally directed, narrow in relation to gonopore length, slightly curved and relatively short ( Fig. 4 F, 25); gonopore 147 long, 168 wide; two rows of loosely arranged idiosoma pores between second and third coxae and between posterior coxal groups. Dorsal lengths of palpal segments: P-I 29; P-II 70; P-III 38; P-IV 73; P-V 43; palp as in male. Dorsal lengths of distal segments of first leg: I-Leg-4 133; I-Leg-5 145; I-Leg-6 215. Dorsal lengths of distal segments of fourth leg: IV-Leg-4 190, IV-Leg-5 191; IV-Leg-6 195. II-Leg-4–5 and III-Leg-4–5 bear stiff short swimming setae; IV-Leg-3–5 bear stiff long swimming setae; dorsal surface of IV-Leg-5 with three long spine-like setae placed in a zigzag pattern.

Etymology. The name refers to the great Mayan civilization that extended throughout the South East Mexico, Peninsula of Yucatán and northern Central America from 400 to 1600 AC.

Discussion. Arrenurus maya sp. nov. is very similar to A. motasi , described by Orghidan and Gruia 1977 from Cuba, in terms of the number and shape of setae on the medial surface of P-II, the shape of the idiosoma, and the presence of setae surrounding the acetabular plates. The main difference is related to size: A. motasi is considerably larger than A. maya . Two other Mexican species, A. catoi Cramer and Cook 1992 and A. apizanus Cramer and Cook 1992 , as well as A. crassus Lundblad from Brazil (Lundblad, 1944) are similar to the present species in the general structure and chaetotaxy of the palp, the acetabular plates bordered by setae, and the overall shape of the idiosoma; a gradual development of the cauda can be observed across these species. A. gibberifer Viets from Uruguay and Brazil (Lundblad, 1944) is similar to A. maya in the structure and chaetotaxy of the palp and in the general shape of idiosoma, however A. gibberifer lacks setose acetabular plates and presents a dorsal protuberance just in the middle of the anterior idiosoma.

Figures

FIGURE 1. SEM images of the idiosoma in dorsal view of males of (A) Arrenurus (Megaluracarus) anitahoffmannae sp. nov., (B) Arrenurus (Megaluracarus) olmeca sp. nov., (C) Arrenurus (Megaluracarus) maya sp. nov., and (D) Arrenurus (Megaluracarus) urbanus sp. nov.. Scale bars 100 µm.

FIGURE 3. SEM images of the idiosma in ventral view of males of (A) Arrenurus (Megaluracarus) anitahoffmannae sp. nov., (B) Arrenurus (Megaluracarus) olmeca sp. nov., (C) Arrenurus (Megaluracarus) maya sp. nov., and (D) Arrenurus (Megaluracarus) urbanus sp. nov.. Scale bars 100 µm.

FIGURE 4. SEM images of the idiosoma in dorsal and ventral views of females of (A-B) Arrenurus (Megaluracarus) anitahoffmannae sp. nov., (C – D) Arrenurus (Megaluracarus) olmeca sp. nov., (E – F) Arrenurus (Megaluracarus) maya sp. nov., and (G – H) Arrenurus (Megaluracarus) urbanus sp. nov.. Scale bars 100 µm.

FIGURES 19 – 25. Arrenurus (Megaluracarus) maya sp. nov.; 19 – 23: Holotype male, 24 – 25: Paratype female. 19. Idiosoma, dorsal view; 20. Idiosoma, lateral view; 21. Palp, medial view; 22. I-Leg- 5 – 6; 23. IV-Leg- 4 – 6; 24. Idiosoma, dorsal view; 25. Idiosoma, ventral view. Scale bars 100 mm.