Aglaodiaptomus clavipes (Schacht, 1897)

Gutiérrez-Aguirre, M. A. & Cervantes-Martínez, A., 2013, Diversity of freshwater copepods (Maxillopoda: Copepoda: Calanoida, Cyclopoida) from Chiapas, Mexico with a description of Mastigodiaptomus suarezmoralesi sp. nov., Journal of Natural History (J. Nat. Hist.) 47 (5 - 12), pp. 479-498 : 482-485

Aglaodiaptomus clavipes (Schacht, 1897)

( Figures 2 , 3 )

Material examined

One dissected, adult female from Laguna Cañada, Chiapas, Mexico (16 ◦ 06 ′ 55 ′′ N, 91 ◦ 40 ′ 44 ′′ W) collected 15.April.2000, slide sealed with Entellan (ECO-CHZ-05520). Six adult females and four adult males from Lago Tziscao , Chiapas, Mexico (16 ◦ 05 ′ 19 ′′ N, 91 ◦ 40 ′ 10 ′′ W) collected 15 April 2000, preserved in 70% ethanol with a drop of glycerine (ECO-CHZ-05521). Two adult females and two adult males used for SEM .

Description

Female. Body measuring 1800–1950 µm excluding caudal setae, fifth pediger without dorsal process; urosomal length 23–24.3% of the body length ( Figure 2A ). Antennule 25-segmented, almost reaching end of prosome. Armament per segment as follows: 1s+1ae; 3s; 1s; 1s; 1s; 1s; 1s; 1s+1sp; 2s; 1s; 2s; 1s+1sp+1ae; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 1s; 2s; 2s; 2s; 5s. Antennular segments 17, 19, 20 and 22 bearing one short, distally curved seta ( Figure 2B ). Metasomal wings not projected, urosome with genital double-somite 1.47–1.5 longer than wide, anal somite, and furcae which are hairy along medial margin, and bear a tiny spine close to insertion of lateral seta (arrowed in Figure 2C ). Fifth leg with Enp shorter than Exp1; Enp unsegmented with two long, distal, feathered setae, which have more than half of the Enp length plus thin, distal spines ( Figure 2D ). Exp2 a curved claw; Exp 3 small but distinct (arrowed in Figure 2E ). Genital somite with short spines laterally; genital field with strong convex plates projected ventrally ( Figure 2F, G ).

Male. Total body length excluding furcal setae 1750–1875 µm; urosome represents 26.6–28.5% of total body length ( Figure 3A ). Left fifth leg with two exopodal segments (left Exp1 arrowed in Figure 3B ); distal segment cylindrical, with one short lamella and one long seta. Left End spiny, long, reaching the distal region of left Exp1 ( Figure 3C ). Right basis with three chitinous, triangular projections on posterior side (one basal and two medial), and one hook-like lamella as long as Exp1 ( Figure 3B ); right Exp1 quadrangular, Exp2 bearing one distal, short aculeus plus one terminal, long spine ( Figure 3B ). Right Enp shorter than Exp1, with a group of spines at tip ( Figure 3D ). Right antennule 22-segmented with armament per segment as follows: 1s+1ae; 3s; 1s; 1s; 1s; 1s; 1s; 1s+1sp; 1s+1ae; 1sps+1ae; 1sps+1ae; 2ae+1sp; 1sps+1ae; 2ae+1s; 2ae+1s; 1sps+1s+2ae; 1ae; 0; 1s; 2s; 2s; 5s+1ae ( Figure 3E ); antepenultimate antennular segment with a thin, hyaline membrane ( Figure 3F ).

Remarks

Aglaodiaptomus clavipes is considered a Nearctic species ( Suárez-Morales et al. 2010), with records in Mississippi, Alberta, Manitoba and northern Mexico. This is the southernmost record of the species. Specimens from Chiapas were assigned to A. clavipes because of the lack of projection in antepenultimate segment of right male A1, the presence of hyaline lamella in the same segment, and the ornamentation of the male P5.

However, some morphological variations were found when Mexican specimens were compared with the illustrated analysis by Wilson and Yeatman (1959) with specimens from USA: the females surveyed here bear shorter antennules, and the spine close to the insertion of furcal lateral seta in the specimens from Chiapas is absent in the female illustrated by Wilson and Yeatman. On the other hand, the right EnpP 5 in Mexican specimens is shorter than right Exp1P 5 in males, in comparison with the sub-equal length in both structures in specimens from the USA.

Figures

Figure 2. Aglaodiaptomus clavipes (Schacht, 1897). Female from Laguna Tziscao, Chiapas. (A) Habitus; (B) right antennule, segments 8–22; (C) urosome, dorsal; (D) Enp and Exp, fifth leg; (E) Exp2, and Exp3 (arrowed), fifth leg; (F) genital somite, ventral; (G) genital somite, lateral. Measures in photos are in µm. Scale bars 50 µm.

Figure 3. Aglaodiaptomus clavipes (Schacht, 1897). Male from Laguna Tziscao, Chiapas. (A) Habitus; (B) fifth leg, caudal (left Exp1 arrowed); (C) fifth leg, left Enp; (D) fifth leg, right Enp; (E) right antennule, segments 8–14; (F) right antennule, antepenultimate segment. Measurements in µm.