Aristocleidus mexicanus, Mendoza-Franco & Osorio & Caspeta-Mandujano, 2015

Mendoza-Franco, Edgar F., Osorio, Marina Tapia & Caspeta-Mandujano, Juan Manuel, 2015, Two new species of Aristocleidus (Monogenea) from the gills of the Mexican mojarra Eugerres mexicanus (Perciformes, Gerreidae) from southwestern Mexico, Parasite (Paris, France) 22, pp. 1-6 : 2-3

Aristocleidus mexicanus n. sp.

urn:lsid:zoobank.org:act:8CE4BC57-1863-4101-9A8D-409B5A1476D3

Type-host: Eugerres mexicanus (Steindachner, 1863) ( Perciformes , Gerreidae ).

Site of infection: Gill lamellae.

Type locality and collection date: Rio Lacantún basin (16°09 0 96.6 00 N, 90°95 0 56.9 00 W), August 2014.

Specimens deposited: holotype, 12 paratypes and 6 vouchers in CNHE (9872, 9873, and 9874, respectively) .

Etymology: named after its host.

Description ( Figs. 1–8 )

Diagnosis (based on 13 specimens collected in August and on 6 collected in January [brackets]) includes the following: Body 515 (425–630; n = 10) long; greatest width 118 (85– 150; n = 10) usually near gonads. Cephalic lobes well developed; each head organ comprising groupings of terminations of cephalic-gland ducts. Pharynx 35 (25–45; n = 10) wide, subspherical. Testis 30–40 (n = 2) long, 18 (17–20; n = 3) wide, pyriform; seminal vesicle comparatively large, fusiform, lying in the midline of body; prostatic reservoir pyriform. Copulatory complex 39 (27–50; n = 12) [47 (43–51; n = 5)] long. Male copulatory organ ( MCO) comprising proximal funnel-shaped base with proximal thickened edge, coiled tube of less than one ring; J-shaped accessory piece, terminally ornate. Prostatic glands conspicuous surrounding dorsal region of prostatic reservoir. Germarium 54 (35–75; n = 6) long, 19 (15–25; n = 5) wide; vaginal vestibule thick walled, internal, communicating with vaginal pore by short duct; vaginal tube moderately long, delicate, extending to ovate seminal receptacle; vitellarium dense, vitelline ducts not observed. Haptor 102 (90–120; n = 9) wide. Ventral anchor 48 (46–50; n = 22) [50 (43–57; n = 8)] long, with variably bent roots, slightly angular union of elongate arcing shaft and straight point (see Au, Sh and Po in Fig. 2 ); base 15 (13–18; n = 17) [18 (16–20; n = 8)]. Dorsal anchor 48 (43–51; n = 15) [51 (48–57; n = 11)] long, with elongate superficial root, short to non-existent deep root, slightly arced shaft, elongate recurved point. Ventral bar 26 (23–30; n = 12) [33 (31–35; n = 3)] long, bilaterally flattened with well-differentiated anteromedial process which is basally covered by a vellum-like fine tissue, a concavity divided into two lateral rounded expansions distally. Dorsal bar 45 (42–47; n = 13) [57 (50–67; n = 3)] long, with slightly expanded ends, indistinct saucer-shaped flange closely appressed to bar proper. Hook 12 (12–13; n = 14) [12 (11–13; n = 14)] long; filamentous hooklet ( FH) loop about 70% shank length.

Differential diagnosis

Placement of this new species in Aristocleidus is based on agreement with the amended generic diagnosis provided by Kritsky and Mendoza-Franco [ 8], i.e., species with gonads overlapping, ventral anchors with deeply incised base forming deep and superficial roots, a coiled tube of the MCO (nonarticulated with the accessory piece) in a clockwise orientation, and haptoral hooks with upright acute thumb, slender shank comprising one subunit and FH loop. A. mexicanus n. sp. most resembles A. hastatus and Aristocleidus sp. from Gerres cinereus from Chautengo Lagoon from Guerrero State (Mexican Pacific) in having ventral bar with conspicuous anteromedial process and by the general morphology of the vaginal tube. A. mexicanus n. sp. differs from these two latter species and A. lamothei mainly in the length (i.e., 46–50 µm vs. 38–43, 34–37, and 26–33, respectively) and shape (i.e., slightly angular union of elongate arcing shaft and point [see Au, Sh and Po, respectively, in Fig. 2 ] vs. point and shaft united at a conspicuous angular bend in A. hastatus and Aristocleidus sp. and evenly curved shaft and point in A. lamothei ) of their ventral anchors and by having a coiled tube of the MCO with less than one ring (a coiled tube of about 1½ in Aristocleidus sp. ), a vaginal tube moderately long (short vaginal tube in A. lamothei and looping in Aristocleidus sp. ), and an ornate distal end of the accessory piece (distally flattened and trifid accessory piece in A. hastatus and A. lamothei , respectively) [ 8, 11].

Figures

Figures 1–8. Aristocleidus mexicanus n. sp. from the gills of Eugerres mexicanus. 1: whole-mount (composite, ventral view); 2: ventral anchor (Sh, shaft; Au, angular union; Po, point); 3: copulatory complex (dorsal view); 4: dorsal anchor; 5: Ventral bar; 6: dorsal bar; 7: vagina; 8: hook. Figures are drawn to the following scales: 100 µm (Fig. 1), 25 µm (Figs. 2–7), and 10 µm (Fig. 8).