Redescription and diagnoses of the genera Profundulus and Tlaloc (Cyprinodontiformes: Profundulidae), Mesoamerican endemic fishes

Abstract

Until recently, the genus Profundulus was classified in two subgenera, Profundulus and Tlaloc, the sole members of the family Profundulidae. Newly discovered molecular data have been used to justify the elevation of these subgenera to genera. Yet morphological analyses to diagnose the two genera are lacking. The aim of this study is to provide a generic diagnosis and a taxonomic key to the species within the family Profundulidae based on morphology. The genus Tlaloc is diagnosed on the basis of five unique characters, among which are the prominent and oval-shaped mesethmoid, exceeding the posterior margins of the vomer; the anterior portion of the parasphenoid making contact with the mesethmoid and extend beyond the center of the mesethmoid; and a reduced autopterotic fossa. Profundulus is diagnosed here based on the following characters: the mesethmoid is small, crescent-shaped, and does not extend beyond the margins of the vomer; the anterior portion of the parasphenoid just contacting the mesethmoid and not extending beyond the center of the mesethmoid; a large autopterotic fossa. For each genus, description and distribution ranges are provided as well as a key for identification of the species.

Keywords:
Distribution; Identification key; Morphological characters; Profundulids; Taxonomy

Resumen

Hasta recientemente, el género Profundulus estuvo integrado por dos subgéneros, Profundulus y Tlaloc, los únicos miembros de la familia Profundulidae. Análisis moleculares recientes se han utilizado como justificación para erigir estos subgéneros a géneros; sin embargo se carecen de los análisis morfológicos que diagnostiquen a ambos géneros. El objetivo de este estudio es proporcionar las diagnosis de los géneros y una clave taxonómica para la identificación de las especies de la familia Profundulidae, basada en la morfología. El género Tlaloc se diagnostica con base en cinco caracteres morfológicos únicos, entre ellos, el mesetmoides prominente y de forma oval, sus bordes exceden el margen posterior del vómer; la porción anterior del parasfenoides está en contacto con el mesetmoides y sobrepasa la parte media de este; la fosa autopterótica es reducida. Profundulus es diagnosticado con base en seis caracteres morfológicos únicos, entre ellos el mesetmoides pequeño, en forma de media luna, y no excede los márgenes del vómer; la porción anterior del parasfenoides, justo en contacto con el mesetmoides y no va más allá de la parte medial de este último hueso; la fosa autopterótica grande. La descripción y los rangos de distribución para cada género, así como una clave para la identificación de las especies, son provistas.

Palabras clave:
Caracteres morfológicos; Clave de identificación; Distribución; Profundúlidos; Taxonomía

INTRODUCTION

The family Profundulidae Hoedeman & Bronner, 1951 is a group of freshwater fishes with a restricted geographical distribution, extending from southern Mexico to Central America (Miller, 1955; Matamoros et al., 2012). It is one of the characteristic elements of the endemic fauna of Central America and the southern Mexico highlands (Miller, 1955), with most of the included species having a restricted distribution range and occurring only in a few adjacent river systems (Matamoros et al., 2012). The Profundulidae is one of the least speciose within the order Cyprinodontiformes (killifishes, pupfishes, and relatives), with only thirteen described species, compared to, for example, approximately 59 nominal species in the family Goodeidae, its sister-group (Nelson et al., 2016; Piller et al., 2022). The profundulids or Middle American killifishes are commonly known as escamudos (Lozano-Vilano, De la Maza-Benignos, 2016).

Until recently, the genus Profundulus was classified in two subgenera, Profundulus and Tlaloc, the sole members of the family Profundulidae (Miller, 1955, 2009; Parenti, 1981). Newly discovered molecular data have been used to justify the elevation of these subgenera to genera by Morcillo et al., (2016). In the absence of a diagnosis, the new clades were supported based on previously documented differences in both subgenera: presence or absence of a humeral spot at the base of the pectoral fin and the number of scales in the preorbital region and base of the caudal fin (Miller, 1955, 2009), as well as by a series of osteological characters of the axial and appendicular skeleton (González-Díaz et al., 2014). These morphological-osteological differences were based on a review of only six species. Our knowledge of the Profundulidae is growing rapidly, and the number of valid species has more than doubled since Miller’s comprehensive revision of Profundulus in 1955. Five new species were described within the genus Profundulus and one in the genus Tlaloc. Additionally, Profundulus balsanus Ahl, 1935 was redescribed and recognized as a valid species (Jamangapé et al., 2016).

External morphological traits (meristic and morphometric) were once the primary sources of characters to distinguish the subgenera and species and to classify profundulid fishes (Miller, 1955, 2009). Different types of morphological characters were gradually introduced to killifish systematics (Parenti, 1981; Costa, 2006) and the morphological analysis of bones has been an important source of morphological characters for hypothesizing relationships among profundulids and cyprinodontoid sister families (Parenti, 1981; Costa, 1998; Ghedotti, Davis, 2013) and between the subgenera and some species of the Profundulidae (e.g., Uyeno, Miller, 1962; González-Díaz et al., 2014).

Profundulids are among the least studied Cyprinodontiformes, and the systematics of the family is still in its early stages, with genera and some species poorly defined, and few descriptions of their osteology (Lozano-Vilano, De la Maza-Benignos, 2016; Morcillo et al., 2016). Several recent molecular studies provide hypotheses on the relationship of profundulid taxa and confirm the monophyly of two previously proposed genera (or subgenera) (e.g., Doadrio et al., 1999; Morcillo et al., 2016; Calixto-Rojas et al., 2021). Molecular data support profundulid clades (genera) which have been scarcely described by morphological characters, highlighting the need to improve the osteological-morphological database for this group. Therefore, the aim of this study is to provide accurate descriptions of morphological characters, including external morphology of body, osteology, neuromasts (cephalic pores), and contact organs in Profundulus and Tlaloc, and to discover additional informative characters to diagnose and characterize both genera. A dichotomous key for the identification of the species of the family Profundulidae is presented.

MATERIAL AND METHODS

The examined material is deposited in the fish collection of the Centro Interdiciplinario de Investigación para el Desarrollo Integral Regional, Oaxaca (CIDOAX); Colección Nacional de Peces, Universidad Nacional Autónoma de México, Mexico (CNPE-IBUNAM ); Field Museum of Natural History, Chicago (FMNH); Louisiana Museum of Natural Science, Louisiana (LSUMZ or LSU MNS); Universidad de Ciencias y Artes de Chiapas, Mexico (MZ-UNICACH). The list of the examined material includes the acronym of the collection and the catalog number, followed by the number of specimens, in parentheses the specimens cleared and stained (c&s), and by their standard-length range.

Measurements and counts follow Miller, (1955) and are presented as percentages of standard length (SL), except for those relative to head morphology, which are expressed as percentages of head length (HL). Seventeen morphometric measurements (in mm) and nine meristic variables were recorded from species of the genera Tlaloc and Profundulus.

Morphometric (Fig. 1): 1, standard length (SL); 2, head length (HL); 3, predorsal length (PL); 4, prepelvic length (PPL); 5, anal origin to caudal base (AOCB); 6, body, greatest depth (BGD); 7, body, greatest width (BGW); 8, caudal peduncle, length (CPL); 9, caudal peduncle, least depth (CPLD); 10, dorsal fin, basal length (DFBL); 11, anal fin, basal length (AFBL); 12, head depth (HD); 13, head width (HW); 14, interorbital, least bony width (IOLBW); 15, orbit length (OL); 16, snout length (SNL); 17, upper jaw length (UJL).

FIGURE 1 |
Morphometric characters, based on sketches of Profundulus in lateral view. Morphometric measurements in the Material and Methods section.

Meristic: 1, dorsal-fin rays; 2, anal-fin rays; 3, caudal-fin rays; 4, pectoral-fin rays; 5, pelvic-fin rays; 6, scales in lateral series; 7, predorsal scales; 8, scales count around the body; 9, scales count around peduncle. The number, morphology, and arrangement of sensorial pores in the cephalic region were studied and named following the methods and terminology of Gosline, (1949) and Miller, (1955).

Osteological characters were obtained from specimens of the 13 profundulid species, cleared and double stained (bone alizarin and cartilage counter-stained with alcian blue), according to the technique described by Taylor, (1967), with some modifications proposed by Taylor, Van Dyke, (1985). The identification of bone elements was based on the bone nomenclature proposed by Gosline, (1961), Parenti, (1981), and Costa, (1998). The terminology of fin rays and the count of vertebrae follows Arratia, (2008) and Schultze, Arratia, (2013). Based on the variation in meristic, morphometric, and osteological characters as well as the distribution of the species, a dichotomous key for the identification of the species of the family Profundulidae was established.

RESULTS

Four species are recognized in the genus Tlaloc (Morcillo et al., 2016; Lozano-Vilano, De la Maza-Benignos, 2016): T. labialis (Günther, 1866), T. candalarius (Hubbs, 1924), T. hildebrandi (Miller, 1950), and T. portillorum (Matamoros & Schaefer, 2010).

Tlaloc Álvarez & Carranza, 1951

TlalocÁlvarez, Carranza, 1951:40 (type species Fundulus labialis Günther, 1866, by monotype).

Diagnosis.Tlaloc, one of the two genera of the family Profundulidae, is diagnosed here by the following combination of characters: The mesethmoid is prominent and oval in shape, extending beyond the posterior margins of the vomer, encompassing the posterior medial extension and touching the lateral ethmoids (Fig. 2B). The anterior portion of the parasphenoid making contact with the mesethmoid and extend beyond the center of the mesethmoid. The autopterotic fossa is reduced (Fig. 2A). The dorsal margin of the interoperculum, with a long extension, is exceeding the edge of the bone (Fig. 3A). The ventral margin of the lacrimal is straight (Figs. 4A–B). Tlaloc is further distinguished from Profundulus by having less than the basal half of the caudal fin densely scaled (except in T. portillorum) (vs. more than the basal half or more densely scaled) (Fig. 5A); by the absence of a humeral spot (vs. humeral spot present); by the origin of the dorsal fin positioned at a vertical line posterior to the origin of the anal fin (vs. origin of the dorsal fin positioned at a vertical line slightly anterior to the origin of the anal fin); by long epiotic processes, extending beyond the second vertebra (vs. short epiotic processes, not extending beyond the first vertebra).

FIGURE 2 |
Ventral view of the neurocranium, in specimens cleared and stained. A. Tlaloc portillorum (MZ-UNICACH 7222, 70.5 mm SL); B. Vomer region of T. candalarius (MZ-UNICACH 3899, 61.7 mm SL); C. Vomer region of Profundulus kreiseri (MZ-UNICACH 7214, 59.6 mm SL); and D. Neurocranium of P. mixtlanensis (MZ-UNICACH 6716, 55.6 mm SL). Abbreviations: V, vomer (Y-shaped); E, lateral ethmoid; M, mesethmoid; P, parasphenoid; AF, autopterotic fossa.

FIGURE 3 |
Lateral view of left jaws, suspensorium and opercular series in specimens cleared and stained. A. Tlaloc portillorum (MZ-UNICACH 7222, 70.5 mm SL); B. Profundulus mixtlanensis (MZ-UNICACH 6716, 55.6 mm SL). Arrow points to dorsal margin of the interoperculum, with a long or short extension. Abbreviations: de, dentary; pm, premaxilla; ra, retroarticular; mx, maxilla; pl, palatine; qu, quadrate; ar, articular; ms, mesopterygoid; io, interopercle; sy, sympletic; hy, hyomandibula; po, preopercle; op, opercle; so, subopercle.

FIGURE 4 |
Ventral view of left lacrimal. A. Tlaloc portillorum (MZ-UNICACH 7222, 70.5 mm SL); B. T. hildebrandi (MZ-UNICACH 2266, 75.1 mm SL); C. Profundulus mixtlanensis (MZ-UNICACH 6716, 55.6 mm SL); and D. P. punctatus (MZ-UNICACH 6632, 67.3 mm SL). Arrow point to ventral margin of the lacrimal.

Description. Morphometric data appear in Tab. 1. Body uniformly slender; head compressed, moderately large (22.4–36.7%). Mouth subterminal to terminal. In T. hildebrandi and T. portillorum, the lower jaw broad, heavy, and protruding so that the upper jaw is included, whereas in T. labialis and T. candalarius both equal in forward projection, or the lower jaw is included in the upper jaw. Greatest body depth in the vertical just posterior to pectoral fin (20.0–32.6%). The females are elongated, and the males are more robust than the females. Dorsal and anal fins located posterior to the half of body length. Caudal peduncle relatively large (16.2–26.4%). Median hypural plate divided into subequal parts by an open groove.

The branching pattern of the cephalic latero-sensory canals in Tlaloc is similar to the general pattern of the Cyprinodontiformes. The supraorbital series follows the Type II designation of Gosline, (1949), with canals between pores 1–2a, 2b–4a, 4b–7; preopercular pores 6–7 (mode = 7); preorbital pores 3–5 (mode = 4); mandibular pores 4–5 (mode = 5); in addition, there are 2 to 4 rostral pores usually developed.

Meristic characters are as follows (Tab. 2): anal: 9–18; dorsal: 7–14; pelvic: 5–7; pectoral: 13–20; caudal: 16–23; vertebrae totals: 33–38; gill rakers on anterior arm of the first arch: 13–19; branchiostegal rays: 6; scales lateral series: 29–39; scales predorsal: 19–26; scales around body: 25–36; scales around peduncle: 16–28.

Coloration. The coloration varies strongly among individuals and ontogenetically. The skin of the head and body may show golden reflections, especially in the opercular region and mid flank. The form and coloration of the nuptial adult male and female are shown in Fig. 6. Unpaired fins (dorsal and anal) are orange in males, with irregular black markings on the dorsal fin, evident in Tlaloc candalarius.

Sexual dimorphism and contact organs. There is little sexual dimorphism in species of the genus Tlaloc. Males are slightly larger than females; the largest specimen recorded was a male from Tlaloc hildebrandi (111.49 mm SL), whereas the maximum size recorded in a female was in Tlaloc labialis (101.93 mm SL). The shape of the anal fin, however, shows a marked sexual difference: the anterior anal rays of the male are not greatly longer than the posterior ones, giving the distal margin of the fin an evenly rounded edge. However, in the female, since the medial rays, from about the sixth to the tenth, are much longer than either the anterior or the posterior rays, the distal margin of the fin is lobate when expanded. Males have contact organs or spinules, articulated with the lateral surfaces of the anal fin rays with some of them conspicuously long; this is the most notable, though not striking difference between males and females of all Tlaloc species (Fig. 7).

FIGURE 5 |
Male general morphology and caudal fin squamation, life colour patterns in: A. Tlaloc labialis; and B. Profundulus punctatus. Solid arrow points to the squamation of the caudal fin, dashed arrow points to the humeral spot.

FIGURE 6 |
Tlaloc candalarius. A. Male (MZ-UNICACH 7567, 71.4 mm SL); B. Female (MZ-UNICACH 7567, 78.8 mm SL); note the orange coloration of the dorsal and anal fins in the male.

FIGURE 7 |
Bony spinules in fin rays of male Tlaloc labialis, indicated by arrow (MZ-UNICACH 6740, 75.7 mm SL), articulated with the lateral surfaces of the anal fin rays.

Geographical distribution. Restricted to the Atlantic slope of Middle America (Fig. 8). From the border between Oaxaca and Chiapas, Mexico, to the center of Honduras, with the exception of Tlaloc portillorum, this is located on both slopes of Honduras, Atlantic and Pacific.

Etymology.Tlaloc in reference to Tlaloc, a deity of water in Aztec mythology (Álvarez, Carranza, 1951).

Nine species are recognized in the genus Profundulus (Morcillo et al., 2016; Del Moral-Flores et al., 2020; Domínguez-Cisneros et al., 2021): P. punctatus (Günther, 1866), P. guatemalensis (Günther, 1866), P. oaxacae (Meek, 1902), P. balsanus, P. kreiseri Matamoros, Schaefer, Hernández & Chakrabarty, 2012, P. mixtlanensis Ornelas-García, Martinez-Ramírez & Doadrio, 2015, P. parentiae Matamoros, Domínguez-Cisneros, Velázquez-Velázquez & McMahan, 2018, P. chimalapensis Del Moral-Flores, López-Segovia & Hernández- Arellano, 2020, and P. adani Domínguez-Cisneros, Velázquez-Velázquez, McMahan & Matamoros, 2021.

Profundulus Hubbs, 1924

ProfundulusHubbs, 1924:12 (type species Fundulus punctatus Günther, 1866, by original designation).

Diagnosis.Profundulus is diagnosed here based on the following characters: The mesethmoid is small, crescent-shaped, and does not extend beyond the margin of the vomer (Figs. 2C–D); the vomer is greatly broadened anteriorly, lacks lateral processes and is in contact with the lateral ethmoids; the anterior portion of the parasphenoid is just in contact with the mesethmoid and does not extend beyond the center of the mesethmoid; the autopterotic fossa is large (Fig. 2D); the dorsal margin of the interoperculum, with a short extension, does not exceed the edge of the bone (Fig. 3B); the ventral margin of the lacrimal slightly concave (Figs. 4C–D). Profundulus is further distinguished from Tlaloc in having more than the basal half of the caudal fin densely scaled (except in P. kreiseri) (vs. less than the basal half of caudal fin densely scaled) (Fig. 5B); by a humeral spot (except in P. adani) (vs. humeral spot absent) (Fig. 5B); by the origin of the dorsal fin positioned at a vertical line slightly anterior to the origin of the anal fin (vs. origin of the dorsal fin positioned at a vertical line posterior to the origin of the anal fin); by short epiotic processes, not extending beyond the first vertebra (except in P. parentiae) (vs. long epiotic processes, extending beyond the second vertebra).

Description. Morphometric data appear in Tab. 2. Body rather robust, elongate; head compressed, large (24.1–35.3%); the interorbital broad (38.2–58.7%) and typically concave or nearly flat. Ascending premaxillary process short and broad and bluntly rounded at the tip. Mouth subterminal, lower jaw broad, heavy and protruding so that upper jaw is included. Dorsal fin rounded in both males and females with its basal length short (11.1–19.2%). Anal fins of males rounded, slightly elongated in females. Caudal peduncle relatively short (11.1–23.2%). Median hypural plate divided into subequal parts by an open groove.

Lateral-line system of sensory canals and pores on the head of Profundulus: The supraorbital series follows the Type II designation of Gosline, (1949), with canals between pores 1–2a, 2b–4a, 4b–7; preopercular pores 6–8 (mode = 7); preorbital pores 3–5 (mode = 4); mandibular pores 4–5 (mode = 5); generally, there is a lack of rostral pores, exceptionally there may be 2 to 4 in some species.

Meristic traits are as follows (Tab. 2): anal: 11–17; dorsal: 10–15; pelvic: 5–7; pectoral: 13–19; caudal: 17–24; vertebrae totals: 31–35; gill rakers on anterior arm of the first arch: 14–22; branchiostegal rays, 6; scales lateral series: 29–35; scales predorsal: 18–29; scales around body: 23–35; scales around peduncle: 16–25.

Coloration. The form and coloration of the nuptial adult male are shown in Fig. 5B. Most of the body dark, often with irregular brown-dark spots on the scales, on the sides of the body on to the caudal fin. A golden yellow blotch covers the operculum and reaches the base of the pectoral fin.

Sexual dimorphism and contact organs. The sexual dimorphism is not very evident in species of the genus Profundulus. However, the males are slightly larger than females; the largest specimen recorded was a male from P. guatemalensis (83.9 mm SL), while the maximum size recorded in a female was in P. adani (77.9 mm SL). In males and females of all species of Profundulus, the dorsal and the anal fins have a similar morphology. Like Tlaloc (Fig. 7) the males of Profundulus have contact organs or spinules, articulated with the lateral surfaces of the anal fin rays with some of them conspicuously long; this is the most notable, though not striking difference between males and females of all Profundulus species.

Geographical distribution. On the Pacific slope, from the río Malinaltepec, río Papagayo basin, of Guerrero, southeastern Mexico, southward to the río Lempa in El Salvador and Honduras; on the Atlantic slope, from the upper reaches of the río Papaloapan of Oaxaca, Mexico, to the ríos Chamelecón and Ulúa in northwestern Honduras (Fig. 8).

Etymology.Profundulus in reference to its presumed primitive relationship to the genus Fundulus (Parenti, 1981).

TABLE 1 |
Morphometric data of Tlaloc and Profundulus species. Asterisk mark the number of specimens analyzed, in parenthesis the average values.

	Tlaloc portillorum58*	T. hildebrandi63*	T. labialis58*	T. candalarius100*	Profundulus punctatus 196*	P. guatemalensis26*
Standard length (mm)	37.6–71.4 (50.4)	37.9–111.5 (58.2)	33.4–101.9 (53.1)	38.8–99.2 (51.6)	36.2–82.2 (50.3)	38.4–83.9 (51.8)
Percents of standard length
Head length	25.7–32.0 (28.9)	26.8–32.2 (28.3)	22.4–31.6 (26.9)	26.3–36.7 (29.4)	26.1–32.6 (29.1)	27.0–31.1 (28.9)
Predorsal length	66.1–73.6 (69.6)	64.2–68.5 (66.3)	65.0–70.4 (67.4)	63.6–73.8 (69.7)	62.2–74.7(68.0)	65.5–71.5 (68.4)
Prepelvic length	47.7–55.2 (51.1)	45.8–51.8 (48.9)	46.8–54.7 (50.6)	48.9–61.1 (53.7)	47.0–57.6 (52.2)	49.8–53.6 (51.5)
Anal origin to caudal base	29.0–36.7 (33.4)	36.3–41.9 (39.1)	32.3–41.8 (36.1)	27.3–39.7 (33.3)	19.3–37.4 (33.2)	31.9–36.7 (34.5)
Body, greatest depth	20.0–27.8 (25.2)	22.1–29.7 (24.6)	20.2–29.9 (24.4)	20.7–32.6 (27.7)	21.0–33.6 (28.5)	25.7–31.5 (29.0)
Body, greatest width	11.8–17.0 (14.5)	12.5–17.6 (14.8)	10.6–18.1 (14.3)	11.5–19.5 (15.6)	14.3–22.8 (18.3)	10.8–18.2 (14.7)
Caudal peduncle, length	16.3–23.5 (19.8)	20.3–26.4 (23.3)	17.8–23.6 (21.5)	16.2–24.0 (19.5)	13.7–21.8 (18.3)	15.5–22.1 (18.8)
Caudal peduncle, Least depth	12.6–15.9 (14.3)	12.0–15.1 (13.4)	12.6–15.1 (13.5)	11.4–16.6 (13.5)	13.9–18.3 (15.7)	14.2–16.1 (15.2)
Dorsal fin, basal length	11.1–16.5 (14.1)	11.7–17.6 (14.1)	11.6–16.4 (14.0)	11.1–17.7 (13.9)	11.1–18.3 (15.0)	12.5–16.6 (14.7)
Anal fin, basal length	12.1–17.4 (14.3)	14.0–19.1 (16.0)	12.7–19.5 (15.5)	12.3–17.5 (14.5)	11.6–20.1 (15.7)	14.3–18.6 (16.0)
Percents of head length
Head depth	55.6–98.0 (67.3)	53.3–85.4 (62.5)	57.5–76.2 (67.0)	56.6–100.1 (68.5)	56.5–94.9 (72.7)	64.8–101.7 (86.0)
Head width	49.3–72.9 (59.6)	49.2–71.0 (64.6)	54.8–70.6 (62.1)	49.2–70.0 (60.7)	58.8–80.6 (68.7)	55.8–75.8 (64.3)
Interorbital, least bony width	37.3–48.7 (42.1)	40.0–48.7 (45.2)	41.1–51.7 (46.2)	34.9–48.3 (42.9)	40.0–53.2 (47.2)	43.3–54.1 (47.3)
Orbit length	21.1–28.6 (24.5)	18.0–28.9 (24.8)	24.9–32.7 (28.6)	19.5–30.6 (26.5)	19.0–29.9 (25.4)	21.6–29.2 (24.0)
Snout length	28.8–35.6 (32.7)	29.8–39.7 (34.9)	29.3–39.7 (33.7)	27.5–38.3 (32.8)	25.6–37.4 (32.3)	28.6–36.9 (33.3)
Upper jaw length	23.9–32.9 (28.3)	26.3–35.3 (31.0)	22.1–31.4 (27.6)	21.5–32.3 (27.7)	16.9–31.7 (25.3)	20.7–33.2(29.6.3)

TABLE 2 |
Meristic data of Tlaloc and Profundulus species. Asterisk mark the number of specimens analyzed, in parenthesis the modal values.

Character

T. labialis 58*

T. candalarius 102*

T. hildebrandi 63*

T. portillorum 58*

P. punctatus202*

P. guatemalensis 26*

P. oaxacae 35*

P. balsanus 22*

P. kreiseri 50*

P. parentiae 41*

P. mixtlanensis 60*

P. adani 71*

P. chimalapensis 38*

Dorsal rays

10–14

9–14 (11)

10–14 (11)

7–14 (11)

10–14 (12)

11–13 (12)

11–13 (12)

11–13 (12)

10–14 (12)

10–13 (12)

10–13 (11)

10–12 (11)

11–14 (13)

Anal rays

13–18 (16)

11–16 (14)

11–16 (15)

9–14 (13)

11–16 (14)

12–15 (14)

13–15 (14)

15–16 (15)

12–16 (14)

13–16 (15)

13–16 (14)

13–16 (14)

14–16 (15)

Pectoral rays

16–20 (18)

14–19 (15)

15–18 (16)

13–17 (15)

14–19 (17)

16–18 (17)

15–18 (16)

15–17 (16)

14–17 (16)

15–17 (16)

15–18 (16)

15–18 (16)

15–18 (17)

Caudal rays

20–23 (20)

16–23 (20)

17–23 (22)

17–23 (20)

18–24 (21)

18–24 (21)

17–22 (20)

18–20 (20)

19–23 (21)

18–22 (20)

18––3 (21)

18–23 (20)

18–23 (20)

Pelvic rays

5–7 (6)

5–7 (6)

5–7 (6)

5–7 (6)

5–7 (6)

6–7 (6)

6 (6)

6 (6)

5–6 (6)

6–7 (6)

6 (6)

6–7 (6)

6 (6)

Lateral scales

33–39 (37)

30–39 (34)

33–37 (36)

29–34 (33)

29–34 (33)

30–33 (33)

29–31 (30)

33 (33)

32–35 (34)

31–33 (33)

31–34 (33)

32–35 (33)

29–32 (31)

Scales predorsal

21–26

19–26 (23)

20–24 (22)

21–26 (23)

18–24 (20)

20–23 (22)

22–29 (25)

21–24 (24)

18–23 (21)

18–22 (22)

21–25 (22)

23–28 (26)

18–21 (19)

Scales around body

28–36

25–35 (31)

27–33 (30)

25–31 (28)

24–30 (26)

26–29 (28)

23–31 (27)

26–29 (28)

23–30 (27)

25–29 (29)

26–34 (28)

25–35 (30)

25–30

Scales around peduncle

18–22 (21)

16–21 (18)

16–21 (18)

16–22 (19)

17–25 (20)

18–23 (19)

16–22 (19)

18–21 (19)

17–21 (19)

17–21 (19)

16–21 (17)

15–18 (17)

17–21 (20)

Vertebrae

37–38 (37)

33–36 (35)

36–37 (36)

33–34 (33)

32–34

32–33 (33)

31–33

33–34 (33)

33–34 (34)

31–32 (32)

33–34 (33)

33–34 (33)

33

Gill rakers

13–18 (16)

14–19 (17)

14–19 (16)

13–17 (15)

15–21 (17)

15–19 (17)

15–18 (16)

14–18 (15)

14–17 (16)

14–22 (18)

16–19 (18)

16–20 (17)

16–19 (18)

Key to identification of Profundulidae species

1a. Humeral spot absent; dorsal fin origin posterior to a vertical through the anal fin origin; mesethmoid prominent and oval-shaped (c&s specimens), protruding from the posterior margins of the vomer (Tlaloc) 2

1b. Humeral spot present (except in P. adani); dorsal fin origin at or anterior to a vertical through the anal fin origin; mesethmoid small and crescent-shaped (c&s specimens), not protruding from the body of the vomer (Profundulus) 5

2a. Lower jaw broad, heavy, and protruding, so that the upper jaw is included 3

2b. Jaws equal, or the lower jaw is included in the upper jaw 4

3a. Thirty-six or 37 vertebrae in total; dark spot at the base of the caudal fin; 36 scales in lateral series (range: 33 to 37); origin of the anal fin to the base of the caudal fin relatively long (36.3–41.9% in the SL). Interior basin of the Chiapas highlands, Mexico (endemic) T. hildebrandi

3b. Thirty-three or 34 vertebrae in total; 33 scales in lateral series (range: 29 to 34); origin of the anal fin to the base of the caudal fin relatively short (29.0–36.7% in SL). Interior basin of the highlands of Honduras (endemic) T. portillorum

4a. Jaws equal; 33 to 36 vertebrae in total; dorsal fin in males with two or three series of black points; middle rays of the anal fin in females, similar in size to that of males. Interior basin, Comitán River and adjacent basins of Mexico and spring at Candelaria, Guatemala T. candalarius

4b. Upper jaw larger than the lower jaw; 37 to 38 vertebrae in total; middle rays of the anal fin in females, much more elongated than that of males. Interior basins of Chiapas, Mexico, and Guatemala T. labialis

5a. Scales on lateral line usually 30 (29–31); predorsal scales 25 (22–29); origin of the anal fin to the caudal-base, relatively short (25.2–32.6% in SL); pattern on the sides of the body with delineated, faint, vertical marks. Pacific slope, upper Verde River basin, Oaxaca, Mexico (endemic) P. oaxacae

5b. More than 30 scales on the lateral line; predorsal scales 19–24 (except in P. adani); origin of the anal fin to the caudal-base, relatively large (31.2–37.1% in SL) 6

6a. Less than basal half of caudal fin densely scaled; head width relatively narrow, its mean value is 60.9% in HL (range 44.5–70.8%). Inland basin of Honduras and Guatemala P. kreiseri

6b. Basal half or more of caudal fin densely scaled; head width relatively large, its mean value varies between 64.3 to 68.7% in HL 7

7a. Predorsal scales usually 26 (23–28); pronounced snout, lower jaw strongly forward projected; relatively large upper jaw (21.1–36.6% in HL). Atlantic slope, upper Papaloapan River basin, Oaxaca, Mexico (endemic) P. adani

7b. Less than 25 predorsal scales; snout is not pronounced, lower jaw is not strongly forward projected 8

8a. Long epiotic processes, surpassing the first epipleural ribs; robust and deep body (26.3–33.8% in SL). Pacific slope, Huatulco River, Oaxaca, Mexico (endemic) P. parentiae

8b. Short epiotic processes, not reaching the first epipleural ribs; slender and deep body (21–31.5% in SL (except in P. punctatus) 9

9a. Body of the adult fish with brown spots on the scales, aligned in such a way that they form a longitudinal band on the sides of the body; humeral spot evident 10

9b. Body of the adult fish without brown spots on the scales on the sides of the body; humeral spot inconspicuous 11

10a. Third neural spine of the caudal complex much thinner than the second; base of the narrow anal fin less than the length of the caudal peduncle. Pacific slope, from the Isthmus of Tehuantepec, Mexico, to Champerico, Guatemala and Atlantic slope, upper Grijalva River basin, Chiapas,Mexico P. punctatus

10b. Third neural spine of the caudal complex, as wide as the second; anal-base fin equal to or greater than the length of the caudal peduncle. Atlantic slope, upper basin of the Coatzacoalcos river (Chimalapas region), Oaxaca, Mexico (endemic) P. chimalapensis

11a. Head typically rectangular and more arched, its dorsal surface generally very rounded; dark band on the sides of the body extending from the vertical of the dorsal fin to the base of the caudal; 4 to 5 preorbital pores. Interior basin of Guatemala and El Salvador, Pacific slope P. guatemalensis

11b. Head conical, its dorsal surface concave to nearly flat; without dark band on the sides of the body; four preorbital pores. Interior basins of Guerrero and Oaxaca, Mexico. Pacific Slope 12

12a. Relatively long upper jaw (24.3–35.9% in HL); 31 to 34 scales on the lateral midline. Pacific slope, upper basin of the Mixteco river, Oaxaca, Mexico (endemic) P. mixtlanensis

12b. Relatively short upper jaw (11.1–23.9% in HL); scales on the lateral midline invariably 33. Pacific slope, Papagayo river basin, Guerrero, Mexico (endemic) P. balsanus

FIGURE 8 |
Geographical distribution of species of the genera Tlaloc and Profundulus in southern Mexico and Central America.

Material examined.Profundulus adani: Mexico: CNPE-IBUNAM 23796, holotype, 64.7 mm SL, Santa Maria Ixclatlan, Oaxaca, 17°51’03”N 97°11’57.4”W, 19 Jun 2018, E. Velazquez & M. J. Anzueto. CNPE-IBUNAM 23797, paratypes, 3, 39.0–59.1 mm SL, Santa Maria Ixcatlan, Oaxaca, 17°51’03”N 97°11’57.4”W, 19 Jun 2018, E. Velazquez & M. J. Anzueto. CNPE-IBUNAM 23798, paratypes, 3, 42.7–48.5 mm SL, Arroyo Nodon, San Miguel Huatla, Oaxaca, 17°47’59”N 97°08’11.9”W, 20 Jun 2018, E. Velazquez & M. J. Anzueto. FMNH 145002, paratypes, 3, 43.1–58.9 mm SL, Santa Maria Ixcatlan, Oaxaca, 17°51’03”N 97°11’57.4”W, 19 Jun 2018, E. Velazquez & M. J. Anzueto. FMNH 145003, paratypes, 3, 67.8–75.0 mm SL, Rio Huatla, San Miguel Huatla, Oaxaca, 17°44’28”N 97°20’15.4”W, 20 Jun 2018, E. Velazquez & M. J. Anzueto. MZ-UNICACH 7382, paratypes, 44 (3 c&s), 36.6–68.2 mm SL, Santa Maria Ixcatlan, Oaxaca, 17°47’57.59”N 97°08’10.40”W, 19 Jun 2018, E. Velazquez & M. J. Anzueto. MZ-UNICACH 7342, paratypes, 18 (2 c&s), 38.3–60.8 mm SL, Arroyo Nodon, San Miguel Huatla, Oaxaca, 17°47’59”N 97°08’11.9”W, 20 Jun 2018, E. Velazquez & M. J. Anzueto. MZ-UNICACH 7343, paratypes, 11, 52.3–77.9 mm SL, Rio Huatla, San Miguel Huatla, Oaxaca, 17°44’28”N 97°20’15.4”W, 20 Jun 2018, E. Velazquez & M. J. Anzueto. Profundulus balsanus: Mexico: MZ-UNICACH 6712, topotypes, 22 (7 c&s), 34.2–64.6 mm SL, Rio Malinaltepec, Guerrero, 17°13’38.03”N 98°40’6.31”W, 26 Apr 2014, M. J. Anzueto. Profundulus chimalapensis: Mexico: MZ-UNICACH 7559, 38 (7 c&s), 35.8–80.3 mm SL, Arroyo Piedra del Rio el Corte, Santa Maria Chimalapa, Oaxaca, 20 Jan 2022, E. Velazquez & M. J. Anzueto. MZ-UNICACH 7560, topotype, 1, 35.1 mm SL, Arroyo la Aurora, Santo Domingo Petapa, Oaxaca, 16°50’17.9”N 95°08’59.8”W, 17 Oct 2021, E. Velazquez & S. Dominguez. Profundulus guatemalensis: Guatemala: LSUMZ 17906, 1 c&s, 52.2 mm SL, Rio las Cabezas, Sanarate, 20 Nov 2014, W. Matamoros. MZ-UNICACH 7194, 12 (4 c&s), 38.3–83.8 mm SL, Balneario el cantil, Rio Cantil, Escuintla, 10 Apr 2017, W. Matamoros & A. E. Gonzalez. MZ-UNICACH 7195, 9 (2 c&s), 38.7–50.3 mm SL, Caserío las Cañas, Arroyo tributario del rio Achihuate, Escuintla, 10 Apr 2017, M. Matamoros & A. E. Gonzalez. MZ-UNICACH 7197, 2, 41.6–42.0 mm SL, Puente la Concha, Arroyo la Concha, Jocotillo Villa Canales, 11 Apr 2017, M. Matamoros & A. E. Gonzalez. MZ-UNICACH 7198, 3, 39.4–57.3 mm SL, Las Cabezas, Puente de las Marias, Santa Rosa Oratoria, 11 Apr 2017, M. Matamoros & A. E. Gonzalez. Profundulus kreiseri: El Salvador: LSUMZ 15105, 2 (1 c&s), 41.57 mm SL, Quebrada Casco de la Hacienda, Parque Nacional Monte Cristo, Santa Ana, 7 Jun 2011, W. Matamoros. MZ-UNICACH 7205, 26 (3 c&s), 37.1–72.6 mm SL, Quebrada los Tecomates, tributario del rio Lempa, Chalatenango, 12 Apr 2017, W. Matamoros & A. E. Gonzalez. MZ-UNICACH 7214, 22 (2 c&s), 38.6–63.3 mm SL, Rio Onuapa, tributario del rio Lempa, Chalatenango, 12 Apr 2017, W. Matamoros & A. E. Gonzalez. MZ-UNICACH 7231, 5, 39.1–4.19 mm SL, Desembocadura del rio Negro, Perquín, 12 Apr 2017, W. Matamoros & A. E. Gonzalez. Profundulus mixtlanensis: Mexico: CIDOAX-300-F1228, 2, 39.0–41.1 mm SL, Yosondúa, Tlaxiaco, Oaxaca, 14 Jun 2014, E. Martinez. CIDOAX-301-F1229, 2, 45.6–49.2 mm SL, Ojo de Agua, Yutanicani, Oaxaca, 14 Jun 2014, E. Martinez. MZ-UNICACH 6716, 26 (9 c&s), 39.3–60.7 mm SL, Ranchería la Soledad, Rio San Isidro, Putla, Oaxaca, 29 Apr 2015, M. J. Anzueto & E. Velazquez. MZ-UNICACH 6717, 3, 53.6–65.5 mm SL, Arroyo tributario del Río Atoyac, colonia Nuevo Tenochtitlan, Putla, Oaxaca, 29 Apr 2015, M. J. Anzueto & E. Velazquez. MZ-UNICACH P 6718, 4, 39.5–53.8 mm SL, Puente Tierra Azul, Putla, Oaxaca, 29 Apr 2015, M. J. Anzueto & E. Velazquez. Profundulus oaxacae: Mexico: MZ-UNICACH 6714, 27 (4 c&s), 35.0–63.1 mm SL, Rio Salado, subcuenca Atoyac, Mitla, Oaxaca, 27 Apr 2015, M. J. Anzueto. MZ-UNICACH 6715, 22 (2 c&s), 39.2–70.5 mm SL, Arroyo Grande tributario del Río la Hormiga, Mitla, Oaxaca, 27 Apr 2015, M. J. Anzueto. Profundulus parentiae: Mexico: CNPE-IBUNAM 28804, holotype, 65.9 mm SL, Rio Huatulco, Santa Maria Huatulco, Oaxaca, 15°50’24.56”N 96°19’48.75”W, 25 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. CNPE-IBUNAM 22805, paratypes, 3, 26.9–35.3 mm SL, Rio Huatulco, Santa Maria Huatulco, Oaxaca, 15°50’24.56”N 96°19’48.75”W, 25 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. FMNH 131755, paratypes, 2, 26.9–35.3 mm SL, Rio Huatulco, Santa María Huatulco, Oaxaca, 15°50’24.56”N 96°19’48.75”W, 25 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. MZ-UNICACH 6574, 6, 27.5–50.2 mm SL, Puente Hondura de Toro, Rio Huatulco, Santa María Huatulco, Oaxaca, 21 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. MZ-UNICACH 6575, 10 (5 c&s), 50.3–68.3 mm SL, Toma de Agua, Rio Huatulco, Santa María Huatulco, Oaxaca, 25 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. MZ-UNICACH 6576, paratypes, 10 (3 c&s), 40.2–67.7 mm SL, Arroyo de la calle central, colonia San Miguel Figueroa, Pochutla, Oaxaca, 15°47’24.1”N 96°24’03.9”W, 21 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar. MZ-UNICACH 6713, paratypes, 10 (4 c&s), 42.5–53.2 mm SL, Camino a Comitlan, Rio la Loma, Santa Maria Colotepec, Oaxaca, 16°01’08.1”N 96°50’41.3”W, 22 Apr 2015, W. Matamoros, M. J. Anzueto, J. A. Jamangape & I. Aguilar MZ-UNICACH 6721, 2 c&s, 44.8–39.3 mm SL, Rio del Rancho Flor de Café, San Gabriel Mixtepec, Oaxaca, 30 Apr 2015, M. J. Anzueto. MZ-UNICACH 7351, 6, 46.3–73.9 mm SL, Puente Mateo Piña, camino a Huatulco, San Mateo Piña, Oaxaca, 22 Sep 2018, E. Velazquez & M. J. Anzueto. Profundulus punctatus: Guatemala: MZ-UNICACH 7169, 32, 37.9–72.6 mm SL, Rio Batza, Colonia Campolla, puente Batza, Quetzaltenango, 9 Apr 2017, A. E. Gomez & E. Velazquez. MZ-UNICACH 7182, 16, 36.3–75.0 mm SL, Rio Nil, puente Nil, El Acintal, Retalhuleo, 9 Apr 2017, A. E. Gomez & E. Velazquez. MZ-UNICACH 7186, 14, 39.4–82.1 mm SL, Rio el Puentecito, Caserio, Retalhuleo, 9 Apr 2017, A. E. Gomez & E. Velazquez. Mexico: MZ-UNICACH 3100, 9, 36.8–57.0 mm SL, Cortina Copainala, Rio Grijalva, Chicoasen, Chiapas, 23 Apr 2009, E. Velazquez. MZ-UNICACH 4332, 6, 38.4-53.6 mm SL, El Chorreadero, Rio Grijalva, Chiapa de Corzo, Chiapas, 23 Oct 2010, E. Velazquez. MZ-UNICACH 4534, 14, 36.7–58.5 mm SL, El Chorreadero, Rio Grijalva, Chiapa de Corzo, Chiapas, 11 May 2011, M. J. Anzueto & E. Velazquez. UNICACH 5067, 3, 36.1–39.3 mm SL, Arroyo Rancho Mujular, Chiapa de Corzo, Chiapas, 12 Apr 2014, M. J. Anzueto & E. Velazquez. MZ-UNICACH 5074, 3, 37.1–46.7 mm SL, Rio Nandalumi, Chiapa de Corzo, Chiapas, 12 Apr 2014, M. J. Anzueto & E. Velazquez. MZ-UNICACH 5143, 4, 36.7–52.7 mm SL, Rio Nandalumi, Chiapa de Corzo, Chiapas, 28 May 2014, M. J. Anzueto & E. Velazquez. MZ-UNICACH 5085, 9, 36.7–52.7 mm SL, Arroyo Rancho Mujular, Chiapa de Corzo, Chiapas, 28 May 2014, M. J. Anzueto & E. Velazquez. MZ-UNICACH 5752, 4, 40.5–43.5 mm SL, Arroyo San Jose, Rio Grijalva, Villaflores, Chiapas, 26 Dec 2014, M. J. Anzueto. MZ-UNICACH 6326, 25, 37.9–72.6 mm SL, Rio Lagartero, Arriaga, Chiapas, 7 Apr 2015, A. E. Gomez & E. Velazquez. MZ-UNICACH 6355, 2 c&s, 67.3–62.7 mm SL, Rio Zapata, Cacahotan, Chiapas, 9 Apr 2015, A. E. Gomez. MZ-UNICACH 6578, 18 (2 c&s), 45.9–56.3 mm SL, Cascada Velo de Novia, Tonala, Chiapas, 8 Apr 2015, A. E. Gomez & E. Velazquez. MZ-UNICACH 6586, 17, 37.6–58.4 mm SL. Puente Rancho Bonito, Jiquipilas, Chiapas, 7 Apr 2015, A. E. Gomez & E. Velazquez. MZ-UNICACH 6632, 21 (3 c&s), 43.3–72.0 mm SL, Rio Cintalapa, Escuintla, Chiapas, 9 Apr 2015, A. E. Gomez & E. Velazquez. Tlaloc candalarius: Guatemala: MZ-UNICACH 7566, topotypes, 18, 39.9–50.9 mm SL, Arroyo del Cenote, La Candelaria, Nenton, 15°56’59.9”N 91°46’53.6”W, 19 Dec 2019, E. Velazquez & M. J. Anzueto. Mexico: MZ-UNICACH 3898, 4, 39.5–40.8 mm SL, Arroyo Teopisca, Teopisca, Chiapas, 8 Aug 2008, E. Velazquez. MZ-UNICACH 3899, 8 (2 c&s), 39.5–99.2 mm SL, Arroyo Teopisca, Teopisca, Chiapas, 6 Oct 2008, E. Velazquez. MZ-UNICACH 5705, 7 (2 c&s), 41.3–45.6 mm SL, Arroyo Santa Barbara, Teopisca, Chiapas, 14 Dec 2014, A. E. Gomez & E. Velazquez. MZ-UNICACH 5709, 1 c&s, 50.3 mm SL, Rio Grande, Comitan, Chiapas, 14 Dec 2014, A. E. Gomez & E. Velazquez. MZ-UNICACH 6224, 1, 54.93 mm SL, Arroyo El Mangal, Socoltenango, Chiapas, 25 Jan 2015, E. Velazquez. MZ-UNICACH 6813, 7 (4 c&s), 39.6–72.1 mm SL, Laguna Chukumaltik, Comitan, Chiapas, 22 Jul 2015, M. J. Anzueto & E. Velazquez. MZ-UNICACH 7245, 5, 26.5–65.4 mm SL, Lagos de Colon, La Trinitaria, Chiapas, 21 Oug 2015, A. E. Gomez & E. Velazquez. MZ-UNICACH 7565, 52 (2 c&s), 38.8–86.4 mm SL, Arroyo Ojo de Agua, Tzimol, Chiapas, 15 Feb 2021, M. J. Anzueto & E. Velazquez. MZ-UNICACH 7567, 6, 53.1–79.3 mm SL, Arroyo Uninajab, Comitan, Chiapas, 6 Feb 2020, E. Velazquez & M. J. Anzueto. Tlaloc hildebrandi: Mexico: MZ-UNICACH 7567, 10 (2 c&s), 42.2–89.2 mm SL, Rio Amarillo, San Cristobal de las Casas, Chiapas, 6 Jul 2016, M. J. Anzueto & E. Velazquez. MZ-UNICACH 4330, 4 (3 c&s), 67.7–111.4 mm SL, Rio Fogotico, San Cristobal de las Casas, Chiapas, 4 May 2006, E. Velazquez. MZ-UNICACH 5694, 10, 47.9–63.1 mm SL, Puente Blanco, San Juan Chamula, Chiapas, 11 Dec 2014, A. E. Gomez & E. Velazquez. MZ-UNICACH 7562, 26, 37.9–63.1 mm SL, Rio San Pedro, Chenalho, Chiapas, 1 Sep 2016, M. J. Anzueto. MZ-UNICACH 5711, 9 (2 c&s), 38.1–104.0 mm SL, Rio Osilhucum, Chenalho, Chiapas, 22 Sep 2007, E. Velazquez. MZ-UNICACH 6194, 9 (1 c&s), 49.5–79.7 mm SL, Arroyo las Limas, Chenalho, Chiapas, 7 Mar 2015, E. Velazquez. Tlaloc labialis: Guatemala: MZ-UNICACH 7233, 2 c&s, 35.5–65.6 mm SL. Rio Selegua, Huehuetan, 20 Apr 2017, W. Matamoros. Mexico: MZ-UNICACH 1402, 1, 64.1 mm SL, Rio Negro, Pueblo Viejo, Cintalapa, Chiapas, 11 Oct 2007, E. Velazquez & M. J. Anzueto. MZ-UNICACH 1305, 16, 41.5–79.7 mm SL, Rio Negro Santa Maria, Cintalapa, Chiapas, 12 Jul 2007, M. J. Anzueto & A. E. Gomez. MZ-UNICACH 3467, 16 (2 c&s), 55.5–73.5 mm SL, Rio Zacalapa, Copainala, Chiapas, 6 Aug 2009, M. J. Anzueto & E. Velazquez. MZ-UNICACH 5274, 1, 67.0 mm SL, Rio Frio, Chiapilla, Chiapas, 1 Oct 2014, E. Velazquez. MZ-UNICACH 5353, 1 c&s, 89.4 mm SL, Rio Ojo de Agua, Emiliano Zapata, Chiapas, 2 Oct 2014, M. J. Anzueto. MZ-UNICACH 6607, 7, 38.9–101.9 mm SL, Rio Mazantic, El Bosque, Chiapas, 8, Mar 2015, A. E. Gomez. MZ-UNICACH 6740, 2 c&s, 64.5–75.7 mm SL, Rio La Venta, Ocozocoautla, Chiapas, 23 Apr 2015, M. J. Anzueto & E. Velazquez. MZ-UNICACH 7563, 26, 33.4–53.1 mm SL, Rio Hondo, Ixtapa, Chiapas, 20 Sep 2019, M. J. Anzueto & E. Velazquez. Tlaloc portillorum: Honduras: LSUMZ 31597, topotypes, 14 (3 c&s), 49.8–70.7 mm SL, Rio Calan, Quebrada Potrerillos, Comayagua, 14°32’31”N 87°52’55”W, 5 Dec 2007, W. Matamoros. MZ-UNICACH 7220, 21 (4 c&s), 40.8–62.9 mm SL, Puente de Piedra a Lepaterique, Francisco Morazan, 15 Apr 2017, W. Matamoros & A. E. Gomenz. MZ-UNICACH 7222, 28 (2 c&s), 37.5–71.3 mm SL, Rio Nacaome, Las Tablas, Francisco Morazan, 15 Apr 2017, W. Matamoros & A. E. Gomez.

DISCUSSION

This study based on morphological characters supports relationships found between genera of Profundulidae as proposed in molecular analyses. Recently Morcillo et al., (2016) resurrected the genus Tlaloc, based on molecular evidence, recognizing the monophyly of the group. Monophyly of Tlaloc is supported in this study by five unique morphological characters: the mesethmoid is prominent and oval in shape, protruding from the posterior margins of the vomer, encompassing the posterior medial extension and making contact with the lateral ethmoids; the upper portion of the parasphenoid makes contact with the mesethmoid and does extent beyond the medial part of this last bone; the autopterotic fossa is reduced; the ventral margin of the lacrimal is straight; the dorsal margin of the interoperculum, with a long extension, exceeds the edge of the bone.

Profundulus was erected and diagnosed by Hubbs, (1924), based on following diagnostic characters: The lateral rims of the genital aperture of the adult female are scarcely pronounced, surrounding not more than the first anal ray; the anal fin in the adult male is lower, instead of higher, than in either the young or the adult female. Miller, (1955) in a review study of Profundulus (Cyprinodontidae) include these two traits and provided three new characters to characterize Profundulus: The shape of the premaxillary process, the nature of the hypural plate (divided into subequal parts by an open groove), and the number of gill rakers. Parenti, (1981) distinguished Profundulus (representing the family Profundulidae) from all other cyprinodontoids by a large autopterotic fossa and a high number of gill rakers on the anterior arm of the first arch (14–23). With the reclassification of Profundulus in two genera, Profundulus and Tlaloc (Morcillo et al., 2016), the diagnostic character of a large autopterotic fossa is now limited to Profundulus. We here add five characters to distinguish Profundulus from Tlaloc: The mesethmoid is small, crescent-shaped, and does not exceed the margins of the vomer; the vomer is greatly broadened anteriorly, lacks lateral processes and is in contact with the lateral ethmoids; the upper portion of the parasphenoid, just in contact with the mesethmoid, does not extend beyond the medial part of this last bone; the dorsal margin of the interoperculum, with a short extension, does not exceed the edge of the bone; the ventral margin of the lacrimal is slightly concave.

Miller (1955) erected two subgenera based on the presence in Profundulus or absence in Tlaloc of conspicuously embedded scales in the preorbital region, the basal half or more of the caudal fin densely scaled, and the presence of a humeral spot in Profundulus or absence in Tlaloc. These characters were found in the analysis of only five described species. Although with most species these characters allow the separation of genera; in our review, including the 13 species currently described, none of these characters functioned as unique characters to diagnose genera.

González-Díaz et al., (2014) described eight osteological differences between the subgenera Profundulus and Tlaloc (seven of the skull and one of the axial skeleton), based on the analysis of only six species. Again, we observed only two characters to be considered of generic significance: the mesethmoid (small vs. large; our analyses corroborate the findings that were previously described by Uyeno, Miller, 1962), and the dorsal margin of the interoperculum (long vs. short extension). The form of the vomer (Y-shaped) was described by Costa (1989) as a character that defines the family Profundulidae; this character was described by González-Díaz et al., (2014) as a triangular-shaped character in Profundulus and Y-shaped in Tlaloc. We however observed Y-shaped vomers in both genera (not triangular) (Figs. 2B–C), so we agree with the description of Costa, (1998).

The current study provides sufficient empirical evidence to confirm the separation and diagnosis of the genera Tlaloc and Profundulus. Analysis of morphological-osteological characters support the clades previously defined by molecular data. The comparative morphology has played an important role in the reconstruction of the evolutionary history and classification of cyprinodontiform fishes, often providing useful phylogenetic information at different taxonomic levels. For this reason, it would be important to incorporate this information to assess alternative hypotheses among members of the family Profundulidae and other groups within the Cyprinodontoidei suborder.

ACKNOWLEDGEMENTS

We thank Esteban Pineda for preparation of the map and to Manuel Anzueto and Fabiola Maza for their technical assistance in the field and laboratory. Comments on a manuscript from Michael Koeck helped to improve the final version substantially. This article is part of the doctoral thesis of the first author (SEDC), a PhD student in Biodiversity and Conservation of Tropical Ecosystems, from the Universidad de Ciencias y Artes de Chiapas (UNICACH) Mexico. The Programa para el Desarrollo Profesional Docente (PRODEP) awarded a support scholarship for graduate studies to SEDC. The manuscript improved substantially thanks to the suggestions of two anonymous critics.

REFERENCES

• Arratia G. Actinopterygian postcranial skeleton with special reference to the diversity of fin ray elements, and the problem of identifying homologies. In: Arratia G, Schultze H-P, Wilson MVH, editors. Mesozoic Fishes 4, Homology and Phylogeny. Verlag Dr. Friedrich Pfeil, München, Germany; 2008. p.49–101.
• Álvarez J, Carranza J. Descripción de un género y especie nuevos de peces Ciprinodontidos procedentes de Chiapas (México). Ciencia. 1951; 11(1–2):40–42.
• Calixto-Rojas M, Lira-Noriega A, Rubio-Godoy M, Pérez-Ponce de León G, Pinacho-Pinacho CD. Phylogenetic relationships and ecological niche conservatism in killifish (Profundulidae) in Mesoamerica. J Fish Biol. 2021; 99(2):396–410. https://doi.org/10.1111/jfb.14727
  » https://doi.org/10.1111/jfb.14727
• Costa WJEM. Descriptive morphology and phylogenetic relationships among species of the Neotropical annual killifish genera Nematolebias and Simpsonichthys (Cyprinodontiformes: Aplocheiloidei: Rivulidae). Neotrop Ichthyol. 2006; 4(1):1–26. https://doi.org/10.1590/S1679-62252006000100001
  » https://doi.org/10.1590/S1679-62252006000100001
• Costa WJEM. Phylogeny and classification of the Cyprinodontiformes (Euteleostei: Atherinomorpha) a reappraisal. In: Malabarba LR, Reis RE, Vari RP, Lucena ZMS, Lucena CAS, editors. Phylogeny and classification of Neotropical Fishes. Porto Alegre: EDIPUCRS; 1998. p.537–60.
• Del Moral-Flores LF, López-Segovia E, Hernández-Arellano T Profundulus chimalapensis, una nueva especie de pez ciprinodóntido (Cyprinodontiformes: Profundulidae) del Río Coatzacoalcos, México. Rev Biol Trop. 2020; 68(4):1185–97. https://doi.org/10.15517/RBT.V68I4.40340
  » https://doi.org/10.15517/RBT.V68I4.40340
• Doadrio I, Carmona JA, Martínez E, De Sostoa A. Genetic variation and taxonomic analysis of the subgenus Profundulus J Fish Biol. 1999; 55(4):751–66. https://doi.org/10.1111/j.1095-8649.1999.tb00715.x
  » https://doi.org/10.1111/j.1095-8649.1999.tb00715.x
• Domínguez-Cisneros SE, Velázquez-Velázquez E, McMahan CD, Matamoros WA. A new species of killifish of the genus Profundulus (Atherinomorpha: Profundulidae) from the upper reaches of the Papaloapan River in the Mexican State of Oaxaca. Ichthyol Herpetol. 2021; 109(4):949–57. https://doi.org/10.1643/i2020156
  » https://doi.org/10.1643/i2020156
• González-Díaz AA, Díaz-Pardo E, Soria-Barreto M, Martínez-Ramírez E. Diferencias Osteológicas entre los Subgéneros Profundulus y Tlaloc (Teleostei: Profundulidae). Int J Morphol. 2014; 32(3):1074–78. http://dx.doi.org/10.4067/S0717-95022014000300053
  » http://dx.doi.org/10.4067/S0717-95022014000300053
• Gosline WA. The sensory canals of the head in some cyprinodont fishes, with particular reference to the genus Fundulus Occas Pap Mus Zool Univ Michigan.1949; 519:1–24. Available from: https://deepblue.lib.umich.edu/handle/2027.42/56957
  » https://deepblue.lib.umich.edu/handle/2027.42/56957
• Gosline WA. Some osteological features of modern lower Teleostean Fishes. Smithsonian Misc Collect. 1961; 142(3):1–42. Available from: https://repository.si.edu/handle/10088/22970
  » https://repository.si.edu/handle/10088/22970
• Ghedotti MJ, Davis MP. Phylogeny, classification, and evolution of salinity tolerance of the North American topminnows and killifishes, family Fundulidae (Teleostei: Cyprinodontiformes). Fieldiana, Life Earth Sci. 2013; (7):1–65. https://doi.org/10.3158/2158-5520-12.7.1
  » https://doi.org/10.3158/2158-5520-12.7.1
• Hoedeman JJ, Bronner FJ. De Orde van de tandkarpertjes. VI. Cyprinodontiformes Berg, 1940. Het Aquarium; 1951; 22(1):6–10.
• Hubbs CL. Studies of the fishes of the order Cyprinodontes. Misc Pubs Univ Michigan Mus Zool.1924; 13:1–31. Available from: https://deepblue.lib.umich.edu/handle/2027.42/56258
  » https://deepblue.lib.umich.edu/handle/2027.42/56258
• Jamangapé JA, Velázquez-Velázquez E, Martínez-Ramirez E, Anzueto-Calvo MJ, Gomez EL, Domínguez-Cisneros SE, Mcmahan CD, Matamoros WA. Validity and redescription of Profundulus balsanus Ahl, 1935 (Cyprinodontiformes: Profundulidae). Zootaxa. 2016; 4173(1):55–65. https://doi.org/10.11646/zootaxa.4173.1.5
  » https://doi.org/10.11646/zootaxa.4173.1.5
• Lozano-Vilano ML, De la Maza-Benignos M. Diversity and status of Mexican killifishes. J Fish Biol. 2016; 90(1):3–38. https://doi.org/10.1111/jfb.13186
  » https://doi.org/10.1111/jfb.13186
• Matamoros WA, Schaefer JF, Hernández CL, Chakrabarty P Profundulus kreiseri, a new species of Profundulidae (Teleostei, Cyprinodontiformes) from northwestern Honduras. ZooKeys; 2012; 227:49–62. http://doi:10.3897/zookeys.227.3151
  » http://doi:10.3897/zookeys.227.3151
• Miller RR. A systematic review of the middle American fishes of the genus Profundulus Misc Pubs Univ Michigan Mus Zool. 1955; 92:1–64. https://deepblue.lib.umich.edu/handle/2027.42/57270
  » https://deepblue.lib.umich.edu/handle/2027.42/57270
• Miller RR. Peces dulceacuícolas de México. CONABIO, México D.F. 2009.
• Morcillo F, Ornelas-García CP, Alcaraz L, Matamoros WA, Doadrio I. Phylogenetic relationships and evolutionary history of the Mesoamerican endemic freshwater fish family Profundulidae (Cyprinodontiformes: Actinopterygii). Mol Phylogenet Evol. 2016; 94:242–51. https://doi.org/10.1016/j.ympev.2015.09.002
  » https://doi.org/10.1016/j.ympev.2015.09.002
• Nelson JS, Grande TC, Wilson MVH. Fishes of the world. John Wiley and Sons, Hoboken. 2016.
• Parenti LR. A phylogenetic and biogeographic analysis of Cyprinodontiform fishes (Teleostei, Atherinomorpha). Bull Am Mus Nat Hist. 1981; 168(4):335–557. http://hdl.handle.net/2246/438
  » http://hdl.handle.net/2246/438
• Piller KR, Parker E, Lemmon AR, Lemmond EM. Investigating the utility of Anchored Hybrid Enrichment data to investigate the relationships among the Killifishes (Actinopterygii: Cyprinodontiformes), a globally distributed group of fishes. Mol Phylogenet Evol. 2022; 173:107482. https://doi.org/10.1016/j.ympev.2022.107482
  » https://doi.org/10.1016/j.ympev.2022.107482
• Schultze H-P, Arratia G. The caudal skeleton of basal teleosts, its conventions, and some of its major evolutionary novelties in a temporal dimension. In: Arratia G, Schultze P, Wilson MVH, editors. Mesozoic Fishes 5–Global Diversity and Evolution; 2013. p.187–246.
• Taylor WR, Van Dyke GC. Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium; 1985; 9(2):107–09.
• Taylor WR. An enzyme method of clearing and staining small vertebrates. Proc U S Natl Mus. 1967; 122(3596):1–17. https://doi.org/10.5479/si.00963801.122-3596.1
  » https://doi.org/10.5479/si.00963801.122-3596.1
• Uyeno T, Miller RR. Relationships of Empetrichthys erdisi, a Pliocene Cyprinodontid fish from California, with remarks on the Fundulinae and Cyprinodontinae. Copeia; 1962; 1962(3):520–32. https://doi.org/10.2307/1441173
  » https://doi.org/10.2307/1441173

ADDITIONAL NOTES

• HOW TO CITE THIS ARTICLE

  Domínguez-Cisneros SE, Domínguez-Domínguez O, Velázquez-Velázquez E, Pérez-Rodríguez R. Redescription and diagnoses of the genera Profundulus and Tlaloc (Cyprinodontiformes: Profundulidae), Mesoamerican endemic fishes. Neotrop Ichthyol. 2023; 21(1):e220089. https://doi.org/10.1590/1982-0224-2022-0089

Edited-by

Paulo Lucinda

Publication Dates

• Publication in this collection
  20 Feb 2023
• Date of issue
  2023

History

• Received
  9 Sept 2022
• Accepted
  8 Dec 2022