taxonID	type	description	language	source
FD15530C8C3AFFBB39AEFEBBEB62E8F7.taxon	description	Figs 1 A – H, 6 A	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3AFFBB39AEFEBBEB62E8F7.taxon	materials_examined	Type host. Kyphosus vaigiensis (Quoy & Gaimard) (Centrarchiformes: Kyphosidae), brassy chub. Type locality. Off Puerto Santa Rosa (6 ° 52 ’ S, 79 ° 55 ’ W), Lambayeque, Peru, South America. Deposited material. Holotype (MUSM 5510); 12 paratypes (MUSM 5511 a – l). Site in host. Gill filaments.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3AFFBB39AEFEBBEB62E8F7.taxon	etymology	Etymology. The specific name is in honor of Dr. Alejandro Francisco Oceguera Figueroa (National Autonomous University of Mexico, Mexico) for his contributions to the field of parasitology.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3AFFBB39AEFEBBEB62E8F7.taxon	description	Description. Based on 13 specimens: 8 mounted in Gomori’s trichrome and 5 mounted in Hoyer’s medium: Body elongate, fusiform, 0.75 – 1.24 (0.99; n = 13) mm long; greatest width 129 – 199 (160; n = 13) usually at level of testis. Tegument scaled in posterior area of trunk and peduncle (Fig. 1 A), scales effortlessly lost in fixed specimens. Cephalic region narrow, with one terminal and 2 bilateral poorly developed cephalic lobes; 3 bilateral pairs of conspicuous head organs; bilateral pair of unicellular cephalic glands lateral to pharynx. Two pairs of eye-spots present, equidistant; accessory chromatic granules absent (Fig. 1 A). Mouth subterminal; pharynx spherical, 38 – 52 (46; n = 12) in diameter; esophagus short; intestinal caeca unbranched, extending from anterior to near posterior end of trunk, not confluent posteriorly. Haptor differentiated from body proper, laterally expanded, 53 – 120 (80; n = 12) long, 208 – 330 (271; n = 12) wide. Anchors dissimilar, with fine conspicuous alae (Fig. 1 B – C). Ventral anchor 46 – 60 (56; n = 11) long; elongate superficial root; well-elongate deep root twice as long as superficial root, medially expanded; curved shaft; and recurved point; point not surpassing level of tip of superficial root; base 3 – 4 (3; n = 11) wide. Dorsal anchor 19 – 26 (22; n = 8) long, with inconspicuous superficial root, short and subquadrangular deep root, evenly curved shaft, and short point; point surpassing level of tip of superficial root; base 6 – 10 (8; n = 8) wide. Ventral bar 159 – 234 (202; n = 13) long, elongate, with mid-ventral longitudinal groove, tapered ends (Fig. 1 D). Dorsal bars 68 – 101 (84; n = 13) long, almost bludgeon-shaped, with spatulate medial end (Fig. 1 E). Fourteen similar hooks, 9 – 11 (10; n = 12) long, each with depressed obtuse thumb, slender and slightly curved shank, and short point (Fig. 1 F); filamentous hook (FH) loop about shank length; hook pair 1 at level of ventral bar; hook pair 5 at level of dorsal bar; other submarginal pairs on lateral haptoral lobes. Genital atrium sclerotized, irregular in shape. Squamodiscs, similar, each 50 – 90 (72; n = 11) long; 132 – 194 (167; n = 12) wide, with 41 – 46 (44; n = 12) concentric rows; dumbbell-shaped rodlets (Fig. 1 G). Male copulatory organ (MCO) sclerotized, J-shaped, with spatulate distal end, 60 – 85 (74; n = 14) long. Middle portion of MCO surrounded by sclerotized sac; distal portion of sac with elongate sclerotized U-shaped process (Figs 1 H, 6 A). Testis ovate, 72 – 118 (95; n = 5) long, 49 – 67 (59; n = 5) wide; vas deferens not looping left intestinal caeca, dilating to form C-shaped seminal vesicle in left side of trunk, posterior to genital atrium; prostatic reservoir, prostatic glands not observed. Ovary elongate, pyriform, 24 – 41 (29; n = 7) long, 50 – 90 (84; n = 7) wide, looping dorsoventrally right intestinal caeca; oviduct, oötype, uterus not observed. Vagina, seminal receptacle not observed. Vitelline follicles dense, extending from posterior level of pharynx to posterior end of trunk, absent in regions of reproductive organs. Eggs not observed.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3AFFBB39AEFEBBEB62E8F7.taxon	discussion	Remarks. Based on the presence of a sclerotized genital atrium, a MCO lacking an accessory piece and a squamodisc with anterior rows of rodlets forming divergent rows (Domingues & Boeger 2008), the newly collected specimens from K. vaigiensis are assigned to Acleotrema. Acleotrema alejandroi sp. nov. is mainly characterized by its MCO, which is J-shaped with a spatulate distal end. The middle portion of MCO is surrounded by a sclerotized sac; and the distal portion of the sac bears an elongated, sclerotized U-shaped process. The new species most closely resembles A. tamatavense (Rakotofiringa, Oliver & Lambert, 1987) Domingues & Boeger, 2007 from Polyamblyodon gibbosum (Pellegrin, 1914) (Sparidae) in Madagascar and A. girellae Johnston & Tiegs, 1922 from Girella tricuspidata (Quoy & Gaimard, 1824) in Australia, due to its MCO which has a J-shaped internal tube. However, A. alejandroi sp. nov. differ from A. tamatavense by the morphology of the sclerotized sac that surround of the MCO (with elongated and sclerotized U-shaped process in the new species vs with a short C-shaped process in A. tamatavense), and by dimensions of the ventral anchors (46 – 60 in the new species vs 25 – 30 in A. tamatavense), ventral bar (156 – 188 in the new species vs 255 – 275 in A. tamatavense), and dorsal bar (68 – 78 in the new species vs 105 – 110 in A. tamatavense). Acleotrema alejandroi sp. nov. is easily differentiated from A. girellae by the sclerotised sac associated with the MCO (without radial musculature in the new species vs with radial musculature in A. girellae) and by the morphology of ventral bar (more robust in the new species).	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	description	Figs 2 A – H, 6 B	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	biology_ecology	Host. Kyphosus vaigiensis (Quoy & Gaimard, 1825) (Centrarchiformes: Kyphosidae), brassy chub.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	materials_examined	Locality. Off Puerto Santa Rosa (6 ° 52 ’ S, 79 ° 55 ’ W), Lambayeque, Peru, South America. Deposited material. 3 voucher specimens (MUSM 5518 a – c)	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	biology_ecology	Site in host. Gill filaments.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	description	Redescription. Based on 3 specimens: 2 mounted in Gomori’s trichrome 1 mounted in Hoyer’s medium: Body elongate, fusiform, 575 – 896 (716; n = 3) long; greatest wide 100 – 115 (106; n = 3) usually at level of testis. Scales not observed. Cephalic region narrow, with one terminal and 2 bilateral poorly developed cephalic lobes; 3 bilateral pairs of conspicuous head organs; bilateral pair of conspicuous unicellular cephalic glands posterolateral to pharynx. Two pairs of eye-spots present, equidistant; accessory chromatic granules absent (Fig. 2 A). Pharynx spherical, 28 – 46 (36; n = 3) in diameter; esophagus short; intestinal caeca unbranched, extending from anterior to near posterior end of trunk, not confluent posteriorly. Haptor differentiated from body proper, laterally expanded, 49 – 68 (57; n = 3) long, 157 – 182 (169; n = 3) wide. Anchors dissimilar (Fig. 2 B – C). Ventral anchor 31 – 37 (33; n = 3); with elongate superficial root; well-elongate, broad deep root, larger than superficial root; straight shaft with two lateral knob at base; and recurved point; point not surpassing level of tip of superficial root; 5 (5; n = 3) wide. Dorsal anchor 19 – 20 (20; n = 2) long, with inconspicuous superficial root; short deep root; slightly curved, broad shaft; and recurved point; surpassing level of tip of superficial root; base 6 – 8 (7; n = 2) wide. Ventral bar 127 – 151 (137; n = 3) long, elongate, with mid-ventral longitudinal groove, tapered ends (Fig. 2 D). Dorsal bars 51 – 73 (59; n = 3) long, curved, with lateral projection (Fig. 2 E). Fourteen similar hooks, 8 – 10 (9; n = 3) long, each with depressed obtuse thumb, slender and slightly curved shank, and short point; filamentous hook (FH) loop about shank length; hook pair 1 at level of ventral bar; hook pair 5 at level of ventral anchor shaft, others submarginal pairs on lateral haptoral lobes (Fig. 2 F). Squamodiscs, similar, each 40 – 57 (49; n = 3) long; 82 – 92 (87; n = 3) wide, with 27 (27; n = 2) concentric rows; dumbbell-shaped rodlets (Fig. 2 G). Genital atrium sclerotized. MCO dagger-shaped, 34 (34; n = 3) long; MCO base ring-shaped; MCO surrounded by weakly sclerotized sac (Fig. 2 I). Ejaculatory bulb strongly muscular, oblong with elongate sclerotized internal tube. Testis ovate, 83 – 104 (93; n = 2) long, 59 – 70 (64; n = 2) wide; vas deferens not looping left intestinal caeca, dilating to form elongate sinuous seminal vesicle in left side of trunk, lateral to ovary; prostatic reservoir, prostatic glands not observed. Ovary elongate, pyriform, 40 – 60 (51; n = 8) long, 42 – 64 (51; n = 8) wide, looping dorsoventrally right intestinal caeca; uterus, oviduct, oötype not observed. Vagina tubular; seminal receptacle well developed (Fig. 2 H). Vitelline follicles dense, extending from posterior level of pharynx to posterior end of trunk, absent in regions of reproductive organs. Eggs not observed.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBC39AEFF0DEC9DEE2C.taxon	discussion	Remarks. This species was described by Yamaguti (1968) as Diplectanum diplobulbus Yamaguti, 1968 from the gills of Kyphosus cinerascens (Forsskål, 7175) in Hawaii. According to Yamaguti (1968), the main morphological characteristic of this species is the presence of two muscular ejaculatory bulbs. However, the examination of paratype and newly collected specimens of A. diplobulbus reveals the presence of a single ejaculatory bulb containing an elongated sclerotized internal tube. New illustrations and morphometric data for A. diplobulbus are provided, and this finding constitutes a new geographical record for this diplectanid.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	description	Figs 3 A – H, 6 C	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	biology_ecology	Host. Kyphosus vaigiensis (Quoy & Gaimard, 1825) (Centrarchiformes: Kyphosidae), brassy chub and Kyphosus elegans (Peters, 1869) (Centrarchiformes: Kyphosidae), Cortez sea chub.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	materials_examined	Locality. Off Puerto Santa Rosa (6 ° 52 ’ S, 79 ° 55 ’ W), Lambayeque, Peru, South America. Deposited material. 10 voucher specimens (MUSM 5515 a – j) from K. vaigiensis and 2 (MUSM 5516 a – b) from K. elegans.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	biology_ecology	Site in host. Gill filaments.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	description	Redescription. Based on 11 specimens: 8 mounted in Gomori’s trichrome 3 mounted in Hoyer’s medium: Body elongate, fusiform, 620 – 789 (705; n = 11) µ long; greatest wide 98 – 152 (126; n = 11) usually at level of ovary. Tegument scaled in posterior area of trunk and peduncle, scales effortlessly lost in fixed specimens (Fig. 3 A). Cephalic region slightly broad, with one terminal and 2 bilateral moderately developed cephalic lobes; 3 bilateral pairs of conspicuous head organs; bilateral pair of inconspicuous unicellular cephalic glands anterior to pharynx. Two pairs of eye-spots present, equidistant; accessory chromatic granules absent (Fig. 3 A). Mouth subterminal; pharynx spherical, 27 – 35 (31; n = 8) in diameter; esophagus short to absent; intestinal caeca unbranched, extending from anterior to near posterior end of trunk, not confluent posteriorly. Haptor differentiated from body proper, laterally expanded, 36 – 92 (58; n = 11) long, 128 – 224 (167; n = 11) wide. Anchors dissimilar, with fine conspicuous alae (Fig. 3 B – C). Ventral anchor 30 – 40 (34; n = 11); with elongate, slightly broad superficial root; deep root larger than superficial root, elongate with quadrangular distal end; curved shaft with two lateral knob at base; and recurved point; point not surpassing level of tip of superficial root; 3 – 5 (4; n = 11) wide. Dorsal anchor 21 – 24 (22; n = 3) long, with inconspicuous superficial root; short, bilobulated, broad deep root; broad shaft, with hatchet-shaped distal extension; and recurved point, surpassing level of tip of superficial root; base 6 – 7 (7; n = 3) wide. Ventral bar 104 – 167 (124; n = 11) long, elongate, broad, with mid-ventral longitudinal groove, tapered ends (Fig. 3 D). Dorsal bars 48 – 80 (59; n = 11) long, curved, with posterolateral projection, conspicuous knob at medial end (Fig. 3 E). Fourteen similar hooks, 8 – 10 (9; n = 10) long, each with depressed obtuse thumb, slender and slightly curved shank, and short point; filamentous hook (FH) loop about shank length; hook pair 1 at level of ventral bar; hook pair 5 at level of ventral anchor shaft, others submarginal pairs on lateral haptoral lobes (Fig. 3 F). Squamodiscs, similar, each 33 – 72 (51; n = 10) long; 53 – 84 (72; n = 10) wide, with 23 – 27 (25; n = 8) concentric rows; dumbbell-shaped rodlets (Fig. 3 G). Genital atrium sclerotized, reticulated. MCO dagger-shaped, 39 – 52 (45; n = 11) long; MCO base ring-shaped; MCO surrounded by weakly sclerotized hamper-shaped sac armed with numerous small plates and distal end with many foliaceous terminations (Fig. 3 H). Ejaculatory bulb strongly muscular, sturdy, oval with elongate sclerotized internal tube (Fig. 3 H). Testis ovate, 59 – 104 (82; n = 8) long, 38 – 88 (68; n = 8) wide; vas deferens not looping left intestinal caeca, dilating to form elongate sinuous seminal vesicle in left side of trunk, lateral to ovary; prostatic reservoir well-elongate and narrow, dorsal to ejaculatory bulb; prostatic glands not observed. Ovary elongate, pyriform, 40 – 60 (51; n = 8) long, 42 – 64 (51; n = 8) wide, looping dorsoventrally right intestinal caeca; uterus elongate, in right side of trunk; oviduct, oötype not observed. Vagina tubular; seminal receptacle well developed. Vitelline follicles dense, extending from posterior level of pharynx to posterior end of trunk, absent in regions of reproductive organs. Eggs not observed.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C3CFFBD39AEF9EEEC86EF43.taxon	discussion	Remarks. This species was described by Yamaguti (1968) as Diplectanum nenue Yamaguti, 1968 from the gills of Kyphosus cinerascens (Forsskål, 7175) in Hawaii. The main morphological characteristic of this species is the presence of numerous foliaceous terminations associated with the distal end of the sclerotized sac that surrounds the MCO. However, this feature has also been reported for Acleotrema nenuoides (Rakotofiringa, Oliver & Lambert, 1987) Domingues & Boeger, 2007, a species described by Rakotofiringa et al. (1987) as Heteroplectanum nenuoides Rakotofiringa, Oliver & Lambert, 1987 from the gills of two sparid fish, Rhabdosargus sarba (Forsskål, 1775) and P. gibbosum, in Tamatave (Madagascar). One of the differences between both species is the presence of a distal extension on the shaft of the dorsal anchor, which is present in A. nenuoides but apparently absent in A. nenue. However, Rakotofiringa et al. (1987) studied the type material of A. nenue and mentioned the presence of a distal extension on the shaft of its dorsal anchor. According to Rakotofiringa et al. (1987), both species are differentiated in terms of the shape of the prostatic reservoir (oval in A. nenue and well-elongate in A. nenuoides), and the host (K. cinerascens of the Kyphosidae for A. nenue and R. sarba and P. gibbosum of the Sparidae for A. nenuoides). Regarding the shape of the prostatic reservoir, our specimens showed an elongated prostatic reservoir, as occurs in A. nenuoides. The examination of the type material A. nenue (USNM 1359367) and photographs and videos provided by Dr. Marcus V. Domingues of a voucher specimen (USNPC 6366302), enabled us to observe a wellelongated prostatic reservoir in A. nenue. Considering that both species, A. nenue and A. nenuoides, are similar in terms of MCO shape, number of rows of squamodisc, prostatic reservoir shape, and dorsal anchor morphology, we propose that A. nenuoides be considered a junior synonym of A. nenue.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	description	Figs 4 A – H, 6 D	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	biology_ecology	Host. Kyphosus elegans (Peters, 1869) and K. vaigiensis (Quoy & Gaimard, 1825).	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	materials_examined	Locality. Off Puerto Santa Rosa (6 ° 52 ’ S, 79 ° 55 ’ W), Lambayeque, Peru, South America. Deposited material. 13 voucher specimens (MUSM 5513 a – m) from K. elegans and 1 (MUSM 5514) from K. vaigiensis.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	biology_ecology	Site in host. Gill filaments.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	description	Redescription. Based on 14 specimens: 8 mounted in Gomori’s trichrome and 6 mounted in Hoyer’s medium: Body elongate, fusiform, 0.83 – 1.40 (1.18; n = 14) mm long; greatest width 130 – 436 (233; n = 14) usually at level of gonads. Tegument scaled in posterior area of trunk and peduncle, scales effortlessly lost in fixed specimens (Fig. 4 A). Cephalic region narrow, with one terminal and 2 bilateral poorly developed cephalic lobes; 3 bilateral pairs of conspicuous head organs; bilateral pair of unicellular cephalic glands lateral to pharynx. Two pairs of eye-spots present, equidistant; accessory chromatic granules absent (Fig. 4 A). Mouth subterminal; pharynx spherical, 34 – 57 (48; n = 9) in diameter; esophagus short to absent; intestinal caeca unbranched, extending from anterior to near posterior end of trunk, not confluent posteriorly. Haptor differentiated from body proper, laterally expanded, 49 – 108 (73; n = 9) long, 274 – 432 (341; n = 9) wide. Anchors dissimilar, with fine conspicuous alae (Fig. 4 B – C). Ventral anchor 61 – 78 (71; n = 14) long; with elongate superficial root; well-elongate deep root twice as long as superficial root, medially expanded; curved shaft; and recurved point; point not surpassing level of tip of superficial root; base 3 – 4 (4; n = 14) wide. Dorsal anchor 31 – 43 (37; n = 13) long, with inconspicuous superficial root, short and subquadrangular deep root, evenly curved shaft, and short point; point surpassing level of tip of superficial root; base with surface striate 9 – 11 (10; n = 13) wide. Ventral bar 236 – 482 (327; n = 14) long, elongate, broadly V-shaped, with mid-ventral longitudinal groove, tapered ends (Fig. 4 D). Dorsal bars 64 – 125 (90; n = 14) long, almost bludgeon-shaped, with spatulate medial end (Fig. 4 E). Fourteen similar hooks, 9 – 11 (10; n = 13) long, each with depressed obtuse thumb, slender and slightly curved shank, and short point; filamentous hook (FH) loop about shank length; hook pair 1 at level of ventral bar; hook pair 5 at level of ventral anchor base, others submarginal pairs on lateral haptoral lobes (Fig. 4 F). Squamodiscs, similar, each 35 – 171 (70; n = 11) long; 173 – 333 (235; n = 8) wide, with 59 – 61 (60; n = 2) concentric rows; dumbbell-shaped rodlets with three lateral projections (Fig. 4 G). Genital atrium sclerotized, corrugated with fingerprint-shaped. MCO sclerotized, almost club-shaped, composed of two nested tubes (external and internal tube), 129 – 206 (161; n = 14) long; external tube with cone-shaped, strongly corrugated with triangular expansion in distal end; spined internal tube with five large spines in middle region, distal portion of internal tube uncovered by external tube but covered by strong muscular bulb (Fig. 4 H). Testis ovate, lobulated, 113 – 253 (187; n = 9) long, 73 – 165 (111; n = 9) long; vas deferens not looping left intestinal caeca, dilating to form small reniform seminal vesicle in left side of trunk, posterior to MCO; prostatic reservoir, prostatic glands not observed. Ovary elongate, pyriform, 35 – 57 (43; n = 7) long, 99 – 133 (119; n = 7) wide, looping dorsoventrally right intestinal caeca; oviduct, oötype, uterus not observed. Vagina, seminal receptacle not observed. Vitelline follicles dense, extending from posterior level of pharynx to posterior end of trunk, absent in regions of reproductive organs. Eggs not observed.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C30FFB139AEFF0DED4FE9A3.taxon	discussion	Remarks. Acleotrema oliveri (León-Régagnon, Pérez-Ponce de León & Garcia Prieto, 1997) Domingues & Boeger, 2007 was proposed by León-Régagnon et al. (1997) as Heteroplectanum oliveri León-Régagnon, Pérez-Ponce de León & Garcia Prieto, 1997 parasitizing K. elegans in Chamela bay, Jalisco, Mexico. León-Régagnon et al. (1997) described and illustrated the MCO of A. oliveri as a tube proximally spined. However, our observation of the type material (CNHE 2728 – 2729, holotype and paratype) and the newly collected specimens revealed that the MCO is club-shaped, composed of two nested tubes (external and internal tube). The external tube exhibits a cone-shaped, is strongly corrugated, and has a triangular expansion at the distal end, while the internal tube is spined along its entire length, with five large spines in the middle region. In newly collected specimens of A. oliveri, we confirmed the presence of a medially expanded deep root of the ventral anchors and a lobulated testis, which were not mentioned in the original description of A. oliveri. Additionally, tegument scaling in the posterior area of the trunk and peduncle were also observed. The redescription presented herein supplements the original description with details of the internal anatomy, sclerotized structures (MCO, anchors and bars) and provided new whole-mount drawing of A. oliveri, as well as morphometric data. Domingues & Boeger (2007) analyzed specimens of Acleotrema sp., deposited in the Queensland Museum (QM no. GL 13653 – 13657), obtained from the gills of K. vaigiensis off Green Island, Queensland, Australia, and noted their conspecificity with A. oliveri. However, certain characteristics, such as the elongate sac associated with the MCO, were not observed due the poor condition of specimens. Considering that A. lamothei and A. serrulopenis also exhibit a spined MCO, the identification of these specimens requires verification. Consequently, the presence of A. oliveri on K. vaigiensis confirms the observations made by Domingues & Boeger (2007). Moreover, the presence of A. oliveri in the Southeastern Pacific Ocean off Peru represents a new geographical record.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	description	Figs 5 A – H, 6 E	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	biology_ecology	Host. Kyphosus vaigiensis (Quoy & Gaimard, 1825) (Centrarchiformes: Kyphosidae), brassy chub.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	materials_examined	Locality. Off Puerto Santa Rosa (6 ° 52 ’ S, 79 ° 55 ’ W), Lambayeque, Peru, South America. Deposited material. 4 voucher specimens (MUSM 5517 a – d) from K. vaigiensis.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	biology_ecology	Site in host. Gill filaments.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	description	Redescription. Based on 4 specimens: 2 mounted in Gomori’s trichrome and 2 mounted in Hoyer’s medium: Body elongate, fusiform, 520 – 992 (814; n = 4) µ long; greatest width 106 – 299 (203; n = 4) usually at level of MCO. Scales not observed. Cephalic region narrow, with one terminal and 2 bilateral inconspicuous cephalic lobes; 3 bilateral pairs of conspicuous head organs; unicellular cephalic glands not observed. Two pairs of eye-spots present, equidistant; accessory chromatic granules absent (Fig. 5 A). Mouth subterminal; pharynx spherical, 31 – 39 (35; n = 2) in diameter; esophagus absent; intestinal caeca unbranched, extending from anterior to near posterior end of trunk, not confluent posteriorly. Haptor differentiated from body proper, laterally expanded, 68 – 113 (88; n = 3) long, 182 – 319 (234; n = 3) wide. Anchors dissimilar (Fig. 5 B – C). Ventral anchor 57 – 69 (64; n = 3) long; elongate superficial root; well-elongate deep root, almost twice as long as superficial root, medially expanded; curved shaft; and recurved point; point surpassing level of tip of superficial root; base 3 – 5 (4; n = 3) wide. Dorsal anchor 37 – 42 (39; n = 3) long, with inconspicuous superficial root, short and subquadrangular deep root, evenly curved shaft, and short point; point surpassing level of tip of superficial root; base 11 – 15 (13; n = 3) wide. Ventral bar 130 – 258 (189; n = 4) long, elongate, broadly W-shaped, with mid-ventral longitudinal groove, tapered ends posteriorly directed (Fig. 5 D). Dorsal bars 62 – 105 (83; n = 4) long, curved, with spatulate medial end (Fig. 5 E). Fourteen similar hooks, 10 – 11 (10; n = 3) long, each with depressed obtuse thumb, slender and slightly curved shank, and short point; filamentous hook (FH) loop about shank length; hook pair 1 at level of ventral bar; hook pair 5 at level of ventral anchor base, others submarginal pairs on lateral haptoral lobes (Fig. 5 F). Squamodiscs, similar, each 31 – 87 (71; n = 3) long; 146 – 287 (214; n = 3) wide, with 42 – 48 (45; n = 3) concentric rows; dumbbell-shaped rodlets (Fig. 5 G). Genital atrium not observed. MCO sclerotized, tubular, elongate, 45 – 55 (48; n = 3) long, surrounded by thorny sheath; MCO surrounded by weakly sclerotized sac, spatulate distally with lateral folds (Fig. 5 H). Testis ovate, 40 (40; n = 1) long, 36 (36; n = 1) long; vas deferens, seminal vesicle, prostatic reservoir, prostatic glands not observed. Ovary elongate, 82 (82; n = 1) long, 56 (56; n = 1) wide, looping dorsoventrally right intestinal caeca; oviduct, oötype uterus not observed. Vagina, seminal receptacle not observed. Vitelline follicles dense, extending from posterior level of pharynx to posterior end of trunk, absent in regions of reproductive organs. Eggs not observed.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
FD15530C8C31FFB139AEFE64EA3EEF43.taxon	discussion	Remarks. This species was originally placed in Diplectanum Diesing, 1858 by Yamaguti (1968), based on specimens collected on K. cinerascens in Hawaii and later transferred to Acleotrema by Domingues & Boeger (2007). According to Domingues & Boeger (2007), this species is characterized by its distinctive spicule-shaped cirrus. The redescription presented in this study complements the original description by providing additional details on the MCO, anchors, bars and hooks. Additionally, we provided the first whole-mount drawing of A. spiculare, along with morphometric data. This finding represents a new geographical record for this diplectanid.	en	Santillan, Angel L., Cruces, Celso L., Mondragón-Martínez, Aarón, Rojas, Rosa Martínez-, Chero, Jhon D. (2025): New and previously described Acleotrema species (Monogenea, Diplectanidae) parasitizing sea chubs (Centrarchiformes: Kyphosidae) in the Southeastern Pacific Ocean. Zootaxa 5570 (3): 533-548, DOI: 10.11646/zootaxa.5570.3.5, URL: https://doi.org/10.11646/zootaxa.5570.3.5
