Gyrodactylus jarocho sp. nov. and Gyrodactylus xalapensis sp. nov. (Platyhelminthes: Monogenea) from Mexican poeciliids (Teleostei: Cyprinodontiformes), with comments on the known gyrodactylid fauna infecting poeciliid fish Author Rubio-Godoy, Miguel Author Paladini, Giuseppe Author García-Vásquez, Adriana text Zootaxa 2010 2509 1 29 journal article 10.5281/zenodo.196033 a86ba3e8-b241-4166-a37a-5abb4b60edcc 1175-5326 196033 Gyrodactylus xalapensis sp. nov. ( Figures 2 , 39–46 ; Table 3 ) Type host: Heterandria bimaculata Heckel (“twospot livebearer”, “guatopote manchado”). Site of infection: Fins. Type locality: Río Pixquiac, Xalapa, Veracruz, México ( 19°28'39''N , 96°57'00''W ). Type material: Eight specimens were studied for light microscopy. The holotype and three paratypes are deposited in the Parasitic Worm Collection at The Natural History Museum ( BMNH reg. nos. 2010.3.11.10 and 2010.3.11.11–13, respectively) London, UK . In addition, four paratypes are deposited in the Colección Nacional de Helmintos ( CNHE reg. no. 7131), Instituto de Biología, Universidad Nacional Autónoma de México , México City. Notes: * Except soft body parts, which were measured from holotype and/or smaller sample sizes. 1Based on the measurement of a single specimen. Abbreviations : TBL = total body length; TBW = total body width; OL×W = haptor length × width; APL×W = anterior pharynx bulb length × width; PPL×W = posterior pharynx bulb length × width; MCOL ×W (NoS) = male copulatory organ (MCO) length × width (number of small spines only - principal spine not included in the count); HTL = hamulus total length; HA = hamulus aperture distance; HPSW = hamulus proximal shaft width; HPL = hamulus point length; HDSW = hamulus distal shaft width; HSL = hamulus shaft length; HICL = hamulus inner curve length; HAA = hamulus aperture angle; HPCA = hamulus point curve angle; IHAA = inner hamulus aperture angle; HRL = hamulus root length; VBW = ventral bar width; VBL = ventral bar length; VBPML = ventral bar process-to-mid length; VBML = ventral bar median length; VBPL = ventral bar process length; VBMemL = ventral bar membrane length; DBL = dorsal bar length; DBW = dorsal bar width; MHTL = marginal hook total length; MHSL = marginal hook shaft length; MHSiL = marginal hook sickle length; MHSiPW = marginal hook sickle proximal width; MHToeL = marginal hook toe length; MHSiDW = marginal hook sickle distal width; MHA = marginal hook aperture; MHI/AH = marginal hook instep / arch height. FIGURE 30. Principal Components Analysis plot (Factor1 vs Factor2) of the 13 point-to-point measurements made on 45 gyrodactylids collected from a range of poeciliid hosts. Separation of the specimens is principally influenced by the hamulus total length (HTL), shaft length (HSL), point length (HPL) and aperture distance (HA) acting along Factor1 in a negative direction, and the inner (CosIHAA) and outer (CosHAA) hamulus angles acting along Factor1 in a positive direction. The total length (MHTL) and the shaft length (MHSL) of the marginal hook are key variables in the separation of specimens along Factor2. The raw ellipses highlight the specimens of Gyrodactylus xalapensis sp. nov. from Heterandria bimaculata Heckel ( 1 ), and Gyrodactylus jarocho sp. nov. from Xiphophorus hellerii Heckel ( 2 ). Plot codes: a . Gyrodactylus bullatarudis Turnbull, 1956 from Poecilia mexicana Steindachner ; b . G. bullatarudis from X. hellerii ; c . G. j a ro c h o sp. nov. from X. hellerii ; d. G. xalapensis from H. bimaculata ; e . G. bullatarudis paratype from Poecilia sphenops Valenciennes ; f. Gyrodactylus costaricensis Kritsky & Fritts, 1970 from P. sphenops ; g. Gyrodactylus gambusiae Rogers & Wellborn, 1965 from Gambusia affinis Baird & Girard ; h. Gyrodactylus pictae Cable , van Oosterhout, Barson & Harris, 2005 from Micropoecilia (= Poecilia ) picta Regan ; i. Gyrodactylus turnbulli Harris, 1986 from Poecilia reticulata Peters ; j. Gyrodactylus poeciliae Harris & Cable, 2000 from Poecilia caucana Steindachner ; k. Gyrodactylus milleri Harris & Cable, 2000 from P. caucana ; l. Gyrodactylus cytophagus Paperna, 1968 from Aplocheilichthys pumilus Boulenger ; m. Gyrodactylus rasini Lucký, 1973 from X. hellerii . Etymology: Named after the city of Xalapa (Veracruz, México ), from whose vicinity samples were taken. Description: Body 262 (245–275) long; 68 (60–75) wide at the level of the uterus. Anterior bulb of pharynx 13.7 long, 30.4 wide; posterior pharynx bulb 12.9 long, 42.7 wide. Haptor spherical, 53 (50–55) long, 54 (50–58) wide. Male copulatory organ (MCO) observed on a single specimen, 11.9 long, 10.4 wide, spherical, armed with one large spine and a single ring of 4 spines (2 medium sized upwardly pointing terminal spines, 2 small central spines whose points face the large spine) ( Figure 46 ). MCO positioned off centre, posterior to the posterior pharynx bulb. Hamulus total length 47.2 (43.3–49.6); shaft length 31.3 (30.2– 32.6); point 21.4 (19.1–23.4) long with a 32.2° (28.6–36.3°) aperture; root proportionately short and approximately rectangular in lateral aspect, one third to half the diameter of the hamulus in the region of the dorsal bar attachment point; 11.9 (10.3–13.7) long ( Figures 39, 44 ). Ventral bar articulation points on the hamuli prominent. Dorsal bar attachment points small, anterior edge marks a sharp angle on union with hamulus. Dorsal bar 22.2 (19.4–25.7) long, 1.7 (1.1–2.3) wide; narrow at its union with the hamulus, the dorsal bar quickly thickens and gradually tapers towards the centre which is marked by a small median notch on the posterior edge ( Figures 39, 44 ). Ventral bar 30.7 (26.4–34.7) long; 30.3 (27.9–32.1) wide. Ventral bar processes prominent, broad, 10.9 (8.7–12.4) long; anterior edge of the processes join the ventral bar proper one quarter in along its length, posterior edge attaches to the lateral extremity of the ventral bar proper close to its posterior edge. Median section of the ventral bar proper rectangular. Ventral bar membrane lingulate, posterior edge rounded 15.0 (12.3–16.5) long; lateral margins not thickened, median zone of membrane striated ( Figures 39, 44 ). Marginal hook 25.8 (24.5–27.2) long; shaft length 20.9 (20.2–22.3); sickle proper 5.0 (4.7–5.3) long; sickle base slender; toe triangular, distance from tip to union with marginal hook shaft 1.6 (1.3–1.8) long; toe bridge proportionately long and gently forward sloping. Sickle heel pronounced, circular to square-ish; sickle proximal width 4.1 (3.5–4.4). Sickle shaft slightly angled forward; sickle point delicate terminating at a point beyond the line of the toe. Sickle distal width 3.4 (3.0–3.8); sickle aperture 4.3 (4.0–4.4) ( Figures 40–42, 45 ). FIGURE 31. Principal components analysis plot (Factor1 vs Factor2) of Gyrodactylus bullatarudis Turnbull, 1956 , Gyrodactylus cytophagus Paperna, 1968 , Gyrodactylus poeciliae Harris & Cable, 2000 , Gyrodactylys rasini Lucký, 1973 and Gyrodactylus xalapensis sp. nov. (13 ln -transformed variables; n = 29 specimens). The specimens of G. xalapensis sp. nov. (ellipse 1) are clearly separated from G. rasini (ellipse 2). Separation of the specimens is effected by the several hamulus variables acting along Factor1 (total length (HTL), shaft length (HSL), point length (HPL), aperture distance (HA), distal shaft width (HDSW) and the proximal shaft width (HPSW)) and by point curve angle of the hamulus (CosHPCA), the total length (MHTL) and shaft length (MHSL) of the marginal hook acting through Factor2. Plot codes: a. G. bullatarudis from Poecilia mexicana Steindachner ; b. G. bullatarudis from Xiphophorus hellerii Heckel ; d. G. xalapensis sp. nov. from Heterandria bimaculata Heckel ; e. G. bullatarudis paratype from Poecilia sphenops Valenciennes ; j. G. poeciliae from Poecilia caucana (Steindachner) ; l. G. cytophagus from Aplocheilichthys pumilus (Boulenger) ; m. G. rasini from X. hellerii . TABLE 4. Morphological characters of poeciliid Gyrodactylus spp. Re-measured in this study.

Measurement TBL	G. bullatarudis Turnbull, 1956 from Poecilia sphenops Valenciennes (USNPC 1181–21 & 1181–23) (n = 2) * 384 (345–423)	G. costaricensis Kritsky & Fritts, 1970 from Poecilia sphenops Valenciennes (USNPC 1181–7, 10 & 15) (n = 3) 408 ± 28.4 (375–428)	G. cytophagus Paperna, 1968 from Aplocheilichthys pumilis Boulenger (MRAC–M.T.35.944) (n = 1) –	G. gambusiae Rogers & Wellborn, 1965 from Gambusia affinis Baird & Girard (USNPC 908–19/20) (n = 1) ** 640	G. milleri Harris & Cable, 2000 from Poecilia caucana Steindachner (BMNH 1999.4.12.1) (n = 1)*** 305
TBW	97 (91–103)	75 ± 11.9 (83–94)	–	65	55
OL×W	67 (62–71) × 79 (76–82)	–	–	95 × 65	85 × 93
APL × W	29.4 × 20.5	29.0 ± 1.41 (28–30) × 28.5 ± 0.71 (28–29)	–	–	–
PPL × W	–	–	–	–	–
MCOL×W (NoS)	9.3 × 9.6 (4 spines)	–	–	9.3 × 8.6	–
HTL	56.0 ± 0.97 (55.3–56.7)	71.7 ± 0.76 (71.2–72.5)	54.2	50.2	56.2
HA	38.1 ± 4.06 (35.3–41.0)	19.4 ± 0.65 (18.7–20.0)	19.8	19.8	19.8
HPSW	9.4 ± 0.77 (8.9–9.9)	11.7 ± 0.86 (10.9–12.6)	7.6	9.9	8.1
HPL	24.7 ± 0.29 (24.5–24.9)	26.3 ± 0.92 (25.3–27.2)	23.6	24.2	28.4
HDSW	4.3 ± 0.37 (4.1–4.6)	4.6 ± 0.13 (4.5–4.7)	7.0	4.8	4.4
HSL	34.2 ± 0.90 (33.5–34.8)	40.4 ± 2.88 (37.8–43.5)	30.0	33.9	35.7
HICL	2.7 ± 0.46 (2.4–3.0)	1.7 ± 0.29 (1.4–2.0)	5.9	4.1	5.3
HAA°	34.9 ± 4.02 (32.1–37.7)	34.6 ± 1.22 (33.4–35.9)	39.1	40.0	36.4
HPCA°	9.7 ± 1.86 (8.4–11.0)	6.2 ± 0.73 (5.4–6.6)	22.7	15.8	15.3
IHAA°	38.1 ± 4.06 (35.3–41.0)	39. 3 ± 1.50 (38.3–41.1)	45.7	47.6	41.3
HRL	19.2 ± 1.74 (18.0–20.4)	32.9 ± 0.87 (32.3–33.9)	20.2	17.4	17.8
VBL	31.3 ± 1.20 (30.4–32.1)	51.7 ± 1.22 (50.9–53.1)	21.2	–	20.0
VBW VBPML	31.7 ± 3.16 (29.5–33.9) 9.4 ± 0.03 (9.3–9.4)	40.9 ± 2.10 (38.8–43.0) 15.0 ± 0.55 (14.7–15.7)	26.2 2.8	– –	27.9 6.8
VBML	6.4 ± 0.15 (6.3–6.5)	10.3 ± 1.02 (9.7–11.5)	4.6	–	6.1
VBPL VBMemL	8.0 ± 0.24 (7.9–8.2) 15.6 ± 0.91 (15.0–16.3)	15.9 ± 0.88 (15.2–16.9) 26.6 ± 1.65 (24.8–27.9)	1.0 13.5	– –	5.7 7.9
DBL	24.3	23.90	23.6	–	18.5
DBW MHTL MHSL MHSiL MHSiPW MHToeL MHSiDW MHA MHI/AH	0.9 23.8 18.9 5.2 4.6 2.3 1.9 5.1 0.4	0.34 26.3 ± 1.07 (25.2–27.2) 20.3 ± 0.85 (19.3–20.9) 6.4 ± 0.30 (6.2–6.7) 4.0 ± 0.05 (3.9–4.1) 1.7 ± 0.22 (1.4–1.8) 1.7 ± 0.23 (1.4–1.9) 5.8 ± 0.28 (5.5–6.1) 0.4 ± 0.13 (0.3–0.5)	1.8 21.1 15.0 6.2 3.8 1.2 4.9 6.2 0.3	– 31.5 22.7 9.4 5.1 2.2 6.4 9.6 0.2	1.6 36.5 ± 1.01 (35.1–38.3)1 27.4 ± 0.79 (26.2–28.7)1 9.4 ± 0.30 (9.0–9.8)1 4.5 ± 0.20 (4.2–4.8)1 2.0 ± 0.07 (1.8–2.0)1 6.0 ± 0.32 (5.6–6.6)1 8.9 ± 0.23 (8.6–9.2)1 0.4 ± 0.05 (0.4–0.5)1

Notes: * Male copulatory organ, pharynx and marginal hook measurements taken from one paratype only; these structures were not visible on the second paratype ; ** the ventral bar was not visible this specimen; *** pharynx and male copulatory organ not visible; 1Marginal hooks come in three different sizes (see Table 6 ). Measurements presented here were made on the small marginal hooks (n = 10) only, which were the most common in the single specimen of G. milleri . Comments: This is the first gyrodactylid species to be described from H. bimaculata . Separation of the gyrodactylids parasitizing poeciliids is most effectively achieved using marginal hook sickle morphology and the discrimination of G. xalapensis sp. nov. from each of the already known species is commented upon under the comments section for each species. Gyrodactylus jarocho sp. nov. and G. xalapensis sp. nov. , however, are described for the first time and can be easily separated on the morphology of the sickle base - approximately triangular in G. j a ro c h o sp. nov. , trapezoidal in G. xalapensis sp. nov. The morphology of the MCO, when present, can also be used to discriminate G. j a ro c h o sp. nov. from G. xalapensis sp. nov. The MCO of G. jarocho sp. nov. is armed with one large spine facing 8 smaller, but differently sized spines, while the MCO of G. xalapensis sp. nov. is armed with one large spine facing 4 smaller sized spines the terminal two of which are larger and appear, in the single MCO-bearing specimen examined here, to be upwardly directed. The marginal sickles of G. xalapensis sp. nov. and G. r a s i n i are morphologically similar but the separation of these two species is possible using the size of the hamulus point curve angle and the lengths of the marginal hook and its shaft.