Allocyclops veracruzanus, Suárez-Morales & Mendoza & Mercado-Salas, 2010

Suárez-Morales, Eduardo, Mendoza, Fredy & Mercado-Salas, Nancy, 2010, A new Allocyclops (Crustacea, Copepoda, Cyclopoida) from bromeliads and records of freshwater copepods from Mexico, Zoosystema 32 (3), pp. 393-407 : 396-400

Allocyclops veracruzanus n. sp.

( Figs 1-6 )

TYPE MATERIAL. –– Mexico. Holotype: Rancho Viejo, near San Andrés Tlalnehuayocan , central sector of the state of Veracruz, altitude 1420 m, from the widespread bromeliad Tillandsia heterophylla Morren , 7.VII. 2008, Fredy Mendoza, adult ♀, dissected, mounted in glycerine sealed with Entellanº (ECO-CHZ-03953).

Allotype: same date, site, and collector as holotype, 1 dissected adult ơ, mounted in glycerine, slide sealed with Entellanº (ECO-CHZ-03954).

Paratypes: same date, site, and collector as holotype, 1 dissected adult ♀, mounted in glycerine, slide sealed with Entellanº (ECO-CHZ-03955); 1 dissected ♀ mounted in glycerine, slide sealed with Entellanº (MNHN-Cp6031); 1 dissected ơ mounted in glycerine, slide sealed with Entellanº (MNHN-Cp6032). — Same locality and date, 4 undissected adult ♀♀, ethanol-preserved; 2 undissected adult ơơ, ethanol-preserved (ECO-CHZ-03955).

Additional specimens: 1 ♀ and 1 ơ specimens processed for observation by SEM at Universidad Autónoma de Aguascalientes. Several copepodites in original sample. TYPE LOCALITY. –– Rancho Viejo,San AndrésTlalnehuayocan (19°32’22”N, 97°00’50”W), Veracruz, Mexico.

ETYMOLOGY. –– The specific epithet makes reference to Veracruz (meaning “true cross”), the name of the Mexican state in which these specimens were collected.

DIAGNOSIS. –– Small, compact body, harpacticoid-shaped. Body without pseudosomite between fifth pediger and genital double somite. Female genital double somite slightly wider than long. Female leg 6 plate on caudal end of proximal third of somite. Anal somite with well-developed anal operculum, triangular, coarsely serrate. Caudal rami short, medialmost and lateralmost terminal setae with breaking planes. Antennule with 11 segments in the female, 15 in the male; segment 7 with three setae, median caudal seta present on the ultimate antennular segment. Antennal basis with exopodal seta. Mandibular palp reduced, with single short seta. Rami of swimming legs 1-4 broad, endopodites and exopodites two-segmented. Endopodite of male leg 3 lacking modified setae. Spine formula 3, 4, 4, 3 in both females and males. Leg 5 composed of proximal segment completely fused to bearing pedigerous somite, armed with a single distal seta; terminal segment also fused, with two equal terminal setae. Leg 6 of male represented by plate with two short, stout setae.

DESCRIPTION

Female

Total body length = 0.55 mm ± 0.03 mm (n = 4) from anterior end of cephalothorax to posterior margin of anal somite. Body elongate, with harpacticoid shape, cephalothorax relatively long, slightly expanded laterally at midlength of cephalosome in dorsal view; lateral margins of pedigers 3 and 4 straight ( Figs 1A ; 5A ). Cephalothorax length = 0.38 ± 0.06 mm (n = 4), representing almost 70% of total body length. Body surface smooth, antennules short, not reaching anterior margin of first pediger. Rostrum short, triangular; labrum armed with 8 blunt central teeth between weakly produced rounded lateral corners, plus two rows of setules on frontal surface ( Fig. 5B ). Urosome formed by four somites, genital somite, two free somites and anal somite; relative ratio of each as: 58: 12.8: 15.2: 14 = 100. Genital double-somite broader than long, with smooth dorsal and ventral surfaces, lateral margins rounded, strongly expanded; distal margin of genital double-somite and two succeeding urosomites with irregularly serrate hyaline membrane ( Figs 2E; 5E, F ). Anal somite relatively large, with posterior margin armed with short spines; anal operculum subtriangular, with coarsely serrate posterior margin, operculum produced to distal third of caudal ramus ( Figs 1B ; 2E). Caudal ramus about two times longer than broad, ornamented with strong spines along entire distal margin. Lateral seta inserted at about midlength of ramus dorsally; dorsal seta about as long as ramus. Lateralmost terminal seta about as long as dorsal seta. Middle terminal setae with proximal breaking planes ( Fig. 1B ).

Antennule ( Fig. 3A ). 11-segmented, armament per segment as follows (s, seta; sp, spine; ae, aesthetasc): 1(8s), 2(2s), 3(5s), 4(1s), 5(sp), 6(2s), 7(3s), 8(2s),

9(2s), 10(2s), 11(7s+1ae).Terminal segments without hyaline membrane.

Antenna ( Figs 2A; 6B ). Four-segmented, basis with one seta on anterior corner and another seta on middle distal margin; exopodal seta present. First endopodal segment with single seta; second segment with four setae. Third endopodal segment with 7 distal setae; inner margin with row of spinules on second and third segments.

Mandible ( Fig. 1C ). Gnathobase with 6 strongly chitinized teeth; 3 ventral teeth bicuspidal, blunt, three dorsal ones acute. Palp reduced, with one short socketed seta.

Maxillule ( Figs 1D ; 5C ). Precoxal arthrite armed with 3 strong chitinized claws and 3 setae on frontal side. Maxillular palp 2-segmented, with 4 subequal setae on proximal article, plus 3 terminal shorter setae, differently armed, on short distal article.

Maxilla ( Figs 1E ; 5C ). Precoxa and coxa unfused; precoxal endite armed with two plumose setae. Coxa with single seta on middle inner margin; coxal caudal surface naked. Proximal basipodal endite with 2 apical setae. Claw-like basal endite bearing 2 or 3 teeth along inner margin. Endopod 2-segmented, each with 2 setae.

Maxilliped ( Figs 1F ; 5C ). Four-segmented. Coxa with two short, strong setae in distal position; pair of unsocketed spinules on middle surface of coxa. Basis with 3 setae, without basal ornamentation. Endopod 2-segmented, first segment with single, stout basal spine furnished spinules. Second endopod reduced, apical, armed with 2 subequal setae, 1 plumose.

Leg 1 ( Figs 1G ; 5D ). Intercoxal sclerite (coupler) with convex rounded projections, surface naked. Coxa with strong inner coxal seta. Basis with slender seta on outer margin; inner margin with strong, pinnate spiniform basipodal seta reaching about midlength of second endopodal segment. Endopod and exopod 2-segmented. Armature as in Table 1.

Leg 2 ( Fig. 2B). Intercoxal sclerite (coupler) and coxa as in leg 1. Basis with slender basipodal seta on outer margin, row of spinules at insertion of seta. Distal margin with moderate disto-medial expansion and row of spines between insertion point of exopod and endopod. Endopod and exopod 2-segmented. Armature as in Table 1.

Leg 3 ( Fig. 2C). Intercoxal sclerite and coxa as in leg 1. Basis as in leg 2. Endopod and exopod 3-segmented; inner margin of exopodal segments with hair-like ornamentation; first exopod with distal row of spinules. Armature as in Table 1.

Leg 4 ( Fig. 2D). Intercoxal sclerite as in legs 1-3. Coxa with strong inner coxal seta, outer margin with row of long, strong spines; additional row of small spines along distal margin. Basis with slender basipodal seta and row of strong spines on outer margin; distal margin with moderate disto-medial expansion armed with row of spines. Endopod and exopod 2-segmented. Endopod longer than exopod. Armature as in Table 1. Outer margins of exopodal segments with hair-like ornamentation; first exopodal segment with row of spines on distal margin.

Leg 5 ( Fig. 2E). Proximal segment fused to somite armed with single, relatively long seta; distal segment fused, with 2 terminal setae equal in length.

Leg 6 ( Fig. 2E). Broad plate located in middle caudal position, near lateral margin of genital somite with laterally directed short dorsal seta and 2 tiny lateral spinules.

B A A, B E

C

C, D D

Male ( Fig. 6A )

Body robust, without hairs or pits on dorsal surface. Smaller, slightly slenderer than female. Total body length of allotype specimen = 0.50mm, cephalothorax length = 0.32 mm, representing almost 64% of total body length. Length of additional male: 0.52 mm, cephalothorax: 0.34 mm. Body and appendages as in females except for sexual dimorphism.

Antennule ( Figs 3B ; 6C ). Geniculate, 15-segmented.

Figures

FIG. 1. — Allocyclops veracruzanus n. sp., ♀ holotype from Veracruz,Mexico (ECO-CHZ-03953):A, habitus,dorsal view;B, anal somite and caudal rami, dorsal; C, mandible; D, maxillule; E, maxilla; F, maxilliped; G, leg 1. Scale bars: A, 100 μm; B-G, 10 μm.

FIG. 5. — Allocyclops veracruzanus n. sp., from Veracruz, Mexico, SEM photographs of non-type specimens, adult ♀: A, habitus, ventral view; B, rostral field and labrum, ventral view; C, mouthparts including maxillules, maxillae and maxillipeds, ventral view; D, first swimming legs, ventral view; E, genital double somite, ventral; F, urosomal somites and caudal rami, ventral view. Scale bars: A, 100 μm; B-E, 10 μm; F, 20 μm.

FIG. 3. — Allocyclops veracruzanus n. sp., from Veracruz, Mexico: A, antennule; B, antennule; C, fifth pedigerous and first urosomal somites, lateral; D, urosome, dorsal view; A, ♀ holotype (ECO-CHZ-03953); B-D, ơ allotype (ECO-CHZ-03954). Scale bars: 20 μm.

FIG. 6. — Allocyclops veracruzanus n. sp., from Veracruz,Mexico,SEM photographs of non-type specimen, adult ơ: A, habitus,dorsal view; B, antenna, dorsal view; C, antennule, dorsal view; D, vestigial sixth legs; E, anal somite showing anal operculum and caudal rami, dorsal view. Scale bars: A, 100 μm; B, E, 10 μm; C, 20 μm; D, 5 μm.