Corresponding author: Martha Angélica Gutiérrez-Aguirre (
Academic editor: D. Defaye
A new species of the genus
Gutiérrez-Aguirre MA, Cervantes-Martínez A (2016) A new species of
The fine structural features of the anatomy of the females and males of freshwater copepods are informative for species recognition. Researchers that have developed this idea concerning free-living copepods are
In the present work is provided an illustrated description of both sexes of one new species of the genus
Morphological analysis. The cephalic appendages, swimming legs and urosome of
The terminology and abbreviations used for the armament of each appendage and structure are based on
The type material was deposited at the Colección de Referencia de El Colegio de la Frontera Sur (
Molecular analysis. Specimens (2 females, 3 males, and 3 copepodites) were preserved after capture in 96% ethanol and prepared for barcoding following standard methods. DNA was extracted using the HOTSHOT method (
Additionally, a search of GenBank and the public data of the Barcode of Life Data System (
Localities and sequence access for specimens surveyed herein, recorded in Mexico and Canada.
Species | Sample ID |
Locality | Lat N | Long W |
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CHU-CRU-0777 | Churchill, Manitoba, Canada |
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BIOUG01701-E09 | Churchill, Manitoba, Canada |
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Cala039 | Minicenote, Quintana Roo, Mexico |
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Cala041 | Minicenote, Quintana Roo, Mexico |
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ZMXII-508 | La Esperanza, Q. Roo, Mexico |
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ZPLMX581 | Kohunlich, Q. Roo, Mexico |
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MAGA-0156 | El Camarón, Sinaloa, Mexico |
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HE-150a | Timilpan, Edo. Mex., Mexico |
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HE-151a | Timilpan, Edo. Mex., Mexico |
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HE-154a | Timilpan, Edo. Mex., Mexico |
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ZPLMX210 | km 25, Edo. Mex., Mexico |
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ZPLMX224 | Kohunlich, Q. Roo, Mexico |
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ZPLMX579 | Kohunlich, Q. Roo, Mexico |
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ZPLMX578 | Kohunlich, Q. Roo, Mexico |
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Cala012 | Boca del Puma, Q. Roo, Mexico |
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Cala016 | Boca del Puma, Q. Roo, Mexico |
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Cala065 | Verde Lucero, Q. Roo, Mexico |
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Cala066 | Verde Lucero, Q. Roo, Mexico |
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Cala069 | Verde Lucero, Q. Roo, Mexico |
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These sequences were downloaded from the
One adult female dissected on one slide:
One adult male dissected on one slide:
Four adult females and five adult males preserved in 90% ethanol with a drop of glycerine.
Two adult females and two adult males preserved in 90% ethanol:
A lagoon called Laguna El Camarón in Avenida Insurgentes, Mazatlán, Sinaloa City, México;
The name of the species means “wedged” in Latin and refers to the chitinous protuberance present on the right disto-lateral corner of the first and second urosomites in females, and on the right caudal ramus on the ventral surface in males.
Adult female: Cuticle surfaces of prosomal somites smooth dorsal and laterally (Fig.
Adult male: The cuticle surfaces of prosomal somites are smooth dorsally and laterally (Fig.
Smooth prosomal somites; body length 1500-1700 µm in paratypes including caudal ramus,
Antennule: 25-segmented, extending beyond the caudal ramus (Fig.
Antenna: Coxa with one long seta; basis with 2 setae; Exp 7-segmented with 1, 3, 1, 1, 1, 1, 4 setae, respectively. Enp 2-segmented, Enp1 with 2 setae plus a row of spine-like setae. Inner lobe of Enp2 bearing 9 long setae, outer lobe with 7 setae and a group of tiny spinules (Fig.
Mandible: Eight teeth on gnathobase (6 of these teeth bifid) with a movable seta at tip. Rectangular, nude coxa. Basis with 4 long setae. Enp two-segmented, Enp1 with 4 setae, Enp2 with 2 distal pectens and 9 long setae. Exp 4-segmented, with 1, 1, 1, and 3 long setae, respectively (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (not figured): Same structure as described and illustrated for
P1-P4: The number of segments on endopods and exopods of P1 to P4, as described for copepods that belong to the
Setation formula of the swimming legs in
Coxa | Basis | Exp | Enp | |
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P1 | 0-1 | 0-0 | I-1; 0-1; I-3-2 | 0-1; 1-2-3 |
P2 | 0-1 | 0-0 | I-1; I-1; I-3-3 | 0-1; 0-2; 2-2-3 |
P3 | 0-1 | 0-0 | I-1; I-1; I-3-3 | 0-1; 0-2; 2-2-3 |
P4 | 0-1 | 1-0 | I-1; I-1; I-3-3 | 0-1; 0-2; 2-2-3 |
Fifth pediger wings and urosome: Right wing of fifth pediger with 2 spines, one dorsal and one ventral (Fig.
Fifth leg (Fig.
Prosomites smooth in dorsal view; left antennule reaching anal somite. Body length 1400-1500 µm in paratypes including caudal ramus,
Right antennule (Fig.
Spiniform process on segment 10 very short, reaching only distal third of its segment; that on segment 11 short, reaching proximal third of the next segment. Convergent spiniform processes on segments 13 and 14. Base of stout spiniform process on segment 13 almost as wide as the length of its segment. Segment 20 is 3.6 times as long as wide, bearing a hook-like projection (less than the half length of penultimate segment) with a smooth hyaline membrane.
Antennule, antenna, mandible, maxillule, maxilla, maxilliped, and P1-P4 as described for female.
Right wing of fifth pediger with 1 tiny dorsal spinule and 1 ventral spine (Fig.
Urosome: Urosomites nude dorsally and ventrally. First urosomite with thin spine on right side and fold on left side (Fig.
P5: Coxal segments with strong spines on caudal view; left and right basis with a lateral seta (Fig.
Left basis with a triangular protuberance on distal margin of frontal surface (Fig.
Right basis basally and distally projected: basal projection rounded whereas distal projection triangle-shaped; one semi-triangular sclerotization on caudal surface of right basis (Fig.
The nucleotide sequence (607 bp) obtained for specimen MAGA-0156 (one adult male), identified as
The
Maximum likelihood tree based on Kimura 2 parameter. The outgroup is
Sequence divergence (
n | Taxa | Comparisons | Min Dist (%) | Mean Dist (%) | Max Dist (%) | SE Dist (%) | |
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Within species | 50 | 7 | 273 | 0 | 1.94 | 5.52 | 0.01 |
Within genus | 54 | 2 | 1054 | 2.34 | 18.28 | 28.19 | 0.01 |
However,
The males of these species show more morphological differences in the fifth leg: the caudal surface of the right basis is bulbose with the oblique, medial, angulose and curved cuticular process in
Results related with the COI gene suggested that
Whereas the distal margins of prosomites are pilose in females and males of
Sequences of the COI gene of
Morphological and genetic differences were found when
1 | Spiniform process on segment 16 of right antennules strongly developed almost as long as its segment width; right basis of P5 with one basal subrectangular protuberance |
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– | Spiniform process on segment 16 of right antennules reduced or absent; right basis of P5 with basal rounded protuberance or without basal protuberance |
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2 | Right basis of P5 with only one lobular protuberance on basal-medial margin, no chitinous lamella or lamellae (on caudal view) |
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– | Right basis of P5 with chitinous lamella or lamellae and with or without rounded protuberance on basal-medial margin (on caudal view) |
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3 | Lobular protuberance of right basis of P5 large; right Exp2 of P5 with two semicircular transverse lamellae, and one longitudinal “Y” shaped ridge; antepenultimate antennular segment with a fang-like process |
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– | Lobular protuberance of right basis of P5 short; right Exp2 of P5 with a low rounded protuberance on outer margin; antepenultimate antennular segment with wide knob-like process |
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4 | Right basis of P5 with one chitinous lamella |
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– | Right basis of P5 with more than one chitinous lamella |
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5 | Chitinous lamella of right basis of P5 semi-circular, on medial margin |
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– | Chitinous lamella of right basis of P5 cuneiform, transversal; or semi-triangular, on caudal side |
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6 | Right Exp2 of P5 with two short semi-circular lamellae (one medial and one lateral); aculeus with 50% of the length of its segment; short spiniform process on antennular segment 14 |
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– | Right Exp2 of P5 with one long quadrangular lamella (on caudal side) aculeus with 70–90% of the length of its segment; long spiniform process on antennular segment 14 |
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7 | Caudal surface of right basis of P5 with one triangular protuberance on distal margin, and one rounded protuberance on basal-medial margin; right Exp2 of P5 nude; right furcal ramus with one wedge-like structure at disto-inner corner of ventral surface |
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– | Caudal surface of right basis of P5 without protuberances, almost rectangular; right Exp2 of P5 with one straight ridge, obliquely directed |
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8 | Left Exp2 of P5 distally truncated and denticulate; aculeus inserted subterminally on Exp2 of P5 |
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– | Left Exp2 of P5 distally attenuated (triangular-shape) aculeus inserted on the second third of Exp 2 of P5 |
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9 | Aculeus shorter than the length of right Exp2 of P5 with long spinules on medial margin; two short semi-circular lamellae on medial margin of right Exp2 of P5; second to forth urosomites with denticles on dorsal surfaces |
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– | Aculeus subequal or longer than the length of right Exp2 of P5 with short spinules on medial margin; one long curved hyaline lamella on right Exp2 of P5; dorsal surfaces of urosomites nude |
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10 | Short spines on rostrum: 2.2–3.0 times longer than width; cuticular surfaces of prosomites nude; 1.37–1.82 mm of body length including furcal ramus |
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– | Long spines on rostrum: 3.5–5.0 times longer than width; hair-like setae on ventral and distal margins from second to fifth prosomites; 0.92–1.1 mm of body length including furcal ramus |
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1 | Hair-like setae only on medial margin of furcal ramus |
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– | Hair-like setae on both, medial and lateral margins of furcal ramus |
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2 | Symmetric genital double-somite, almost parallel lateral margins with short spines on left and right margins |
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– | Asymmetric genital double-somite, bulbose lateral margins with short spines on left and right margins |
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3 | Symmetric genital double-somite, almost parallel lateral margins; two-segmented Enp of P5 bearing one apical spinule longer than the endopodal width |
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– | Asymmetric genital double-somite, bulbose lateral margins; one or two-segmented Enp of P5 bearing two apical spinules shorter than the endopodal width |
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4 | Enp of P5 longer than the inner margin of Exp1 of P5; long lateral sensilla of coxal segment of P5 |
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– | Enp of P5 shorter than the inner margin of Exp1 of P5; short lateral sensilla of coxal segment of P5 |
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5 | One or two urosomites with a chitinous protuberance on the right disto-lateral corner |
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– | Urosomites with straight posterior margins, no protuberances are present |
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6 | Second urosomite with a spine-like protuberance on the right disto-lateral corner; one-segmented Enp of P5 |
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– | Genial double-somite and second urosomite with chitinous protuberance on the right disto-lateral corner; two-segmented Enp of P5 |
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7 | Genital double-somite produced, or curved and wrinkled on the right disto-lateral margin |
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– | Genital double-somite straight on the right disto-lateral margin |
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8 | Two-segmented Enp of P5, as long as medial margin of Exp1; genital double-somite curved and wrinkled on the right disto-lateral margin |
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– | Two-segmented Enp of P5, shorter than the half length of medial margin of Exp1; genital double-somite produced on the right disto-lateral margin |
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9 | One-segmented Enp of P5; left and right spines of genital double-somite inserted at same level; ventral spine of right wing (of last prosomite) directed to the posterior region of the body |
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– | Two-segmented Enp of P5; right spine of genital double-somite inserted more anteriorly than left spine; ventral spine of right wing (of last prosomite) directed to the dorsal region of the body |
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10 | Short spines on rostrum: 1.5–3.6 times longer than width; tiny spines on ventral surface of each prosomites; 1.47–1.87 mm of body length including furcal ramus |
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– | Long spines on rostrum: 3.6–4.0 times longer than width; hair-like setae on ventral and distal margins from second to fifth prosomites; 0.9–1.3 mm of body length including furcal ramus |
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We received grants from the Universidad de Quintana Roo and National Council of Science and Technology (CONACYT) through the Mexican Barcode of Life (MEXBOL) project CONACyT 271108, Red Temática Código de Barras de la Vida (Continuidad de Redes Temáticas). We are grateful with the academic edition of two native English-speaking editors. We thank professors and students of Instituto Tecnológico de Mazatlán (ITMAZ) for collecting zooplankton samples and making them available to us. We are grateful to Danielle Defaye, Y. Ranga Reddy and an anonymous reviewer who made valuable comments and suggestions to improve the manuscript.