Revista de Biología Tropical, ISSN: 2215-2075, Vol. 74 (S2): e20267102, abril 2026 (Publicado Abr. 24, 2026)

First record and range extension of the Cocos batfish,

Ogcocephalus porrectus Garman 1899 (Lophiiformes: Ogcocephalidae),

off the continental Pacific coast of Costa Rica

Arturo Angulo1,2*; https://orcid.org/0000-0002-4587-1446

Angela Jimena Delgado-Murillo1,2; https://orcid.org/0009-0006-9733-7970

Naidely Valeria Vidaurre-Quesada1,2; https://orcid.org/0009-0002-3196-7196

1. Escuela de Biología, Museo de Zoología/Centro de Investigación en Biodiversidad y Ecología Tropical (CIBET), and

Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica. 11501–2060, San

Pedro de Montes de Oca, San José, Costa Rica. arturo.angulosibaja@ucr.ac.cr (*Correspondence), angelajimenadel-

gadomurillo@gmail.com, naidelyvq@gmail.com

2. Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica. 11501–2060, San

Pedro de Montes de Oca, San José, Costa Rica.

Received 30-VIII-2025. Corrected 26-II-2026. Accepted 16-III-2026.

ABSTRACT

Introduction: To date, two species of batfishes of the genus Ogcocephalus have been documented in the Eastern

Pacific Ocean. Ogcocephalus porrectus, originally described from Isla del Coco, Costa Rica, has been regarded as

restricted to waters around Isla del Coco and Isla de Malpelo (Colombia).

Objectives: To report and describe the first record of O. porrectus from the Pacific coast of continental Costa

Rica, thereby extending its known distribution range.

Methods: The specimen supporting this new record was collected with a bottom trawl net off the north Pacific

coast of Costa Rica, at 67 m depth. It was deposited in the Ichthyological Collection of the Museo de Zoología,

Universidad de Costa Rica, under the catalog number UCR 3368-001. Morphometric and meristic data of the

specimen were recorded following standard procedures. Additional material of O. porrectus and O. darwinii was

examined for comparison.

Results: Morphological and coloration traits of the specimen were consistent with with previous descriptions of

O. porrectus, confirming its identification.

Conclusions: This record parallels the recent continental occurrence of O. darwini in Ecuador, since both species

were previously considered insular. Such a finding highlights the role of larval dispersal and sampling gaps on

perceived distribution patterns of batfishes. It also underscores the need for continued ichthyological surveys to

document faunal linkages and to anticipate potential responses of marine biodiversity to environmental change

in the Eastern Pacific.

Keywords: Eastern Tropical Pacific; insular–continental connectivity; biogeography; larval dispersal; ichthyo-

faunal inventories.

RESUMEN

Primer registro y extensión geográfica del pez murciélago de la Isla del Coco, Ogcocephalus porrectus

Garman 1899 (Lophiiformes: Ogcocephalidae), en aguas costeras del Pacífico de Costa Rica

Introducción: Hasta la fecha se han documentado dos especies de peces murciélago del género Ogcocephalus en

el Océano Pacífico Oriental. Ogcocephalus porrectus, descrita originalmente para la Isla del Coco, Costa Rica, se

consideraba restringida a las aguas de esta isla y de la Isla de Malpelo, Colombia.

https://doi.org/10.15517/0bw9vy85

SUPPLEMENT

2Revista de Biología Tropical, ISSN: 2215-2075 Vol. 74 (S3): e20267102, abril 2026 (Publicado Abr. 24, 2026)

INTRODUCTION

The family Ogcocephalidae currently com-

prises 98 valid species distributed across ten

genera (Fricke et al., 2025). Ogcocephalids,

commonly known as batfishes, are character-

ized by their distinctive morphology, including

a dorsoventrally depressed body, a pointed or

rounded head (in dorsal view), and large and

lateral arm-like pectoral fins; a combination of

characters that justify their vernacular designa-

tion (Nelson et al., 2016; Robertson & Allen,

2024). Batfishes are benthic organisms inhabit-

ing tropical and subtropical waters worldwide,

where they move in a waddling manner or by

“walking” slowly, supported by their modified

pectoral and pelvic fins (Nelson et al., 2016;

Robertson & Allen, 2024). Batfishes are car-

nivorous, feeding primarily on crustaceans and

small fishes, which they capture using special-

ized lures and aided by their cryptic appearance

(Nelson et al., 2016; Robertson & Allen, 2024).

The genus Ogcocephalus Fischer 1813 is

the most diverse and taxonomically complex

group within the Ogcocephalidae, with 13 spe-

cies currently recognized as valid (Robertson &

Allen, 2024; Froese & Pauly, 2025). These fishes

are widely distributed in the Western Atlantic

and Eastern Pacific (EP) oceans, in shallow to

moderately deep waters, inhabiting continen-

tal shelves, insular slopes, and rarely estuarine

environments (Nelson et al., 2016; Robertson &

Allen, 2024; Froese & Pauly, 2025). Members of

the genus are distinguished from other ogcoce-

phalids by their relatively elongate body form,

their oval and plate-like gill rakers, the presence

and arrangement of dermal tubercles, and char-

acteristic modifications of the illicium and esca

(Bradbury, 1967, Bradbury, 1980; Robertson &

Allen, 2024).

Two species of Ogcocephalus have been

documented in the EP; Ogcocephalus porrectus

Garman 1899 and Ogcocephalus darwini Hubbs

1958 (Robertson & Allen, 2024; Froese & Pauly,

2025). The first species was originally described

from specimens collected at the vicinity of Isla

del Coco (also known as Cocos Island), Costa

Rica (5°32´45.0´´ N, 86°54´30.0´´ W) (Brad-

bury, 1980). Since then, its confirmed distribu-

tion has been limited to insular environments

in the Eastern Tropical Pacific region (ETP),

specifically the Coco and the Malpelo (Colom-

bia) islands, at depths ranging from 35 to 150

m (Bradbury, 1980; Robertson & Allen, 2024).

Ogcocephalus porrectus can be distinguished

from its congeners by its markedly elongated

body, a slender rostrum, and the presence of

small but well-defined dermal tubercles over

Objetivos: Reportar y describir el primer registro de O. porrectus en la costa pacífica continental de Costa Rica,

ampliando así su distribución conocida.

Métodos: El ejemplar que respalda este nuevo registro fue recolectado con una red de arrastre de fondo, a 64 m de

profundidad, en la costa Pacífico norte de Costa Rica. El espécimen fue depositado en la Colección Ictiológica del

Museo de Zoología, Universidad de Costa Rica, bajo el número de catálogo UCR 3368-001. Se registraron datos

morfométricos y merísticos del ejemplar siguiendo procedimientos estándar, y se examinó, a efectos comparati-

vos, material adicional de O. porrectus y O. darwinii.

Resultados: Los rasgos morfológicos y de coloración del ejemplar coincidieron con descripciones previas de O.

porrectus, confirmando su identificación.

Conclusiones: Este registro es paralelo a la ocurrencia reciente de O. darwini en aguas costeras de Ecuador

continental, ambas especies previamente consideradas como insulares. Tal hallazgo resalta la influencia de la dis-

persión larval y de los vacíos de muestreo en los patrones de distribución percibidos de los peces murciélagos en

la región. Asimismo, enfatiza la necesidad de continuar con inventarios ictiológicos que documenten los vínculos

faunísticos y permitan anticipar posibles respuestas de la biodiversidad marina frente al cambio ambiental en el

Pacífico Oriental.

Palabras clave: Pacífico Tropical Oriental; conectividad insular–continental; biogeografía; dispersión larval;

inventarios ictiofaunísticos.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 74 (S2): e20267102, abril 2026 (Publicado Abr. 24, 2026)

the disk, among other characters (Bradbury,

1980; Robertson & Allen, 2024). Despite being

recognized as a distinctive species, information

on its ecology, abundance, and precise distribu-

tion remains relatively scarce (Bradbury, 1980;

Robertson & Allen, 2024).

Herein, we report the first record of occur-

rence of O. porrectus from the Pacific coast of

continental Costa Rica, extending its known

distribution range. This finding contributes to

the understanding of the diversity and biogeog-

raphy of the Ogcocephalidae in the region and

underscores the importance of continued ich-

thyological surveys along the ETP, particularly

in areas and ecosystems where the fish fauna

remains incompletely documented.

MATERIALS AND METHODS

The specimen supporting this new record

was obtained using a bottom trawl net (12 m

total length, with a 9 m length cone, plus a 3 m

long tube bag; mouth 7 m wide and 2 m high;

and mesh size 2.54 cm), operated by a local

longline vessel off the northern Pacific coast of

Costa Rica. Four trawls, each lasting approxi-

mately 30 minutes and covering an estimated

distance of 1.85 km at a speed of 3.7 km/h,

were conducted within the Gulf of Santa Elena,

Guanacaste. The collection of the specimen

took place on March 6, 2023, at the locality of

Palo Blanco (about 10°57’57.3” N, 85°47’51.9”

W; Fig. 1), at an average depth of 67 m, over

a muddy-sandy substrate. This sampling was

part of the BioMar-ACG project, which aims

to inventory and characterize the marine bio-

diversity of the Área de Conservación Gua-

nacaste (ACG) [see Cortés & Joyce (2020) for

additional details].

Immediately after capture, the specimen

was frozen and transported to the laboratory,

where tissue samples (preserved in 96% etha-

nol) were taken prior to fixation in 10% forma-

lin. The specimen was subsequently preserved

in 70% ethanol and deposited in the Ichthyo-

logical Collection of the Museo de Zoología of

the Universidad de Costa Rica (UCR), under

catalog number UCR 3368-001. Identification

was based on Hubbs (1958), Bradbury (1980)

and Robertson & Allen (2024).

Morphometric measurements (12 in total;

Table 1) were recorded as follows: orbital diam-

eter (OD), greatest diameter of the bony orbit;

interorbital width (IO), narrowest distance

between lateral frontal bones of either side;

rostral length (RL) (measured on ventral side),

distance between upper extent of illicial cav-

ity and anterior tip of rostrum; mouth width

Fig. 1. Map of the capture site of Ogcocephalus porrectus (UCR 3368-001; yellow star) on the Pacific coast of Costa Rica, along

with previously known records (yellow circles) in Coco and Malpelo islands. Occurrence data, based on museum material,

were obtained from Bradbury (1980) and Robertson & Allen (2024). A single point may represent more than one lot or

specimen. The gray line indicates national boundaries, including the twelve nautical mile territorial limit.

4Revista de Biología Tropical, ISSN: 2215-2075 Vol. 74 (S3): e20267102, abril 2026 (Publicado Abr. 24, 2026)

(MW), measured as greatest overall width; illi-

cial cavity width (IW), greatest width of illicial

cavity opening; predorsal length (PD), distance

from center of upper lips to base of first dorsal

fin ray; disk margin length (DM) (measured on

ventral side), distance from posterior swelling

of mandible to posterior base of subopercular

buckler; pectoral fin length (PF), distance from

base to distalmost tip of longest fin ray; anal fin

length (AF), distance from origin of anal fin

to distalmost tip of longest fin ray; dorsal fin

length (DF), distance from origin of dorsal fin

to distalmost tip of longest fin ray; caudal fin

length (CF), distance from base of caudal fin

to distalmost tip. Meristic data (Table 1) were

taken following Bradbury (1980); these include

pectoral (P1), pelvic (P2), dorsal (D), anal (A),

and caudal (C) fin rays counts. Additional

material of O. porrectus and O. darwinii, depos-

ited in the UCR, as well as published data (Bri-

ones-Mendoza et al., 2022), were also examined

and tabulated for comparative purposes.

RESULTS AND DISCUSSION

Morphometric and meristic data of the

examined specimen (Fig. 2), along with addi-

tional comparative material, are provided in

Table 1. Other morphological characteristics

of the specimen include: head depressed, but

elevated above disk; disk triangular; snout

pointed, with a horn-like rostrum projecting

well forward before eyes, and with a mass of

relatively long “hairs” on tip of horn; fish-lure

with three fleshy points, in a small cavity under

horn; spine at lower rear corner of operculum

blunt; eyes on sides of head; gill opening high,

above pectoral fin base; gill rakers as oval plates

covered with small teeth; pectoral and pelvic

fins limb-like; pectoral fins completely sepa-

rated from body; skin covered dorsal fin on tail;

small fleshy anal fin under tail; skin with many

large protruding, bony spines; fringe of hairs

along lower side, from mouth to base of caudal

fin; ventral portion of body completely covered

Table 1

Morphometric and meristic data of Ogcocephalus porrectus from coastal waters of Costa Rica (UCR 3368-001), with

comparative material of O. porrectus and O. darwinii. Morphometric values are expressed as percentages of standard length

(SL).

Measurement / Count

Ogcocephalus porrectus Ogcocephalus darwini

UCR 3368-001 UCR 0737-0007, n = 9 UCR 0788-001 Briones-Mendoza et al.

(2023); n = 1

Min Max n = 1

SL (mm) 78.55 75.13 105.85 102.62 215

OD 7.12 5.51 7.28 6.49 5.12

IO 8.42 7.83 11.62 8.01 8.79

RL 11.29 9.22 14.21 13.2 12.28

MW 11.05 9.47 12.54 8.92 -

IW 4.35 3.31 4.7 4.45 -

PD 65.82 60.44 69.96 62.37 -

DM 45.44 45.38 53.09 51.45 50.6

PF 19.94 18.46 23.38 22.27 15.16

AF 13.05 12.93 16.7 16.22 11.3

DF 8.47 6.77 8.75 8.99 2.7

CF 22.92 19.79 24.73 25.35 14.88

P1 14 12 13 15 14

P2 6 6 6 5 5

D 4 4 4 4 3

A 4 4 4 4 3

C 9 8 8 9 9

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 74 (S2): e20267102, abril 2026 (Publicado Abr. 24, 2026)

with pointed, bony scales; and ventral portion

of tail densely covered with small prickles,

sometimes with a few conical spines along

the midline.

Morphometric, meristic, and other ana-

tomical traits (as described above), together

with the live coloration of the specimen (i.e.,

dorsum pale brown; two large dark blotches

on the nape and several smaller ones along

mid-side; a pale bar beneath the eye; ventral

surface ranging from orange-red to creamy

white; mouth reddish), agree closely with previ-

ous descriptions of O. porrectus (Hubbs, 1958;

Bradbury, 1967, Bradbury, 1980; Robertson

& Allen, 2024). This species can be readily

distinguished from its closest congener in the

ETP, O. darwini, by the following combination

of characters: horn-like rostrum with a mass

of long hairs on tip (vs. few short hairs); flanks

with fringe of hairs (vs. without fringe of hairs);

skin with many large spiny knobs (vs. few small

to medium spiny knobs); and coloration [with

a pair of large dark blotches on nape plus sev-

eral smaller blotches on mid-side vs. two dark

brown stripes (sometimes broken) from top of

head to caudal fin] (Bradbury, 1980; Robert-

son & Allen, 2024). These consistent morpho-

logical traits, supported by multiple diagnostic

characters, provide robust evidence for species

identification even in the absence of molecular

confirmation, especially given that no COI

sequences for O. porrectus are currently avail-

able in public genetic databases (e.g., GenBank

or BOLD).

The detection of O. porrectus in continental

waters of Costa Rica parallels the record of O.

darwini in mainland Ecuador (Briones-Mendo-

za et al., 2022), a species previously considered

endemic to the Galápagos region. These find-

ings highlight recurring patterns in ogcocepha-

lid biogeography (Bradbury, 1967; Bradbury,

1980; Briones-Mendoza et al., 2022), suggesting

that oceanographic processes such as eddy-

driven larval transport, episodic current-medi-

ated dispersal, and/or relaxation of upwelling

fronts may intermittently connect insular and

continental habitats in the ETP (Briones-Men-

doza et al., 2022). Given the limited dispersal

capacity of adult batfishes, such events likely

occur during the planktonic larval stage (Brad-

bury, 1967, Bradbury, 1980; Briones-Men-

doza et al., 2022). The apparent absence of O.

porrectus from continental records until now

may reflect insufficient sampling, as its cryptic

nature and benthic habits make detection chal-

lenging without dedicated surveys (Bradbury,

1967; Bradbury, 1980; Bussing & López, 2009;

Briones-Mendoza et al., 2022; Robertson &

Allen, 2024).

Biogeographically, this continental record

of O. porrectus advances our understanding

of faunal linkages across the ETP and chal-

lenges assumptions of strict insular endemism

in ogcocephalids. The finding suggests that

Central America’s continental margins may

serve as under-explored refuges or transient

habitat for insular species. Documenting these

occurrences is fundamental not only to fill

knowledge gaps in Costa Rica’s marine bio-

diversity (Bussing & López, 2009), but also

to inform broader conservation and manage-

ment efforts. Strengthening ichthyological sur-

veys, particularly of cryptic benthic taxa, is

therefore critical to capture the true extent of

species distributions and to anticipate future

ecological responses to environmental and cli-

matic shifts (Bussing & López, 2009; Briones-

Mendoza et al., 2022).

Future studies should aim to better eluci-

date the oceanographic mechanisms facilitating

larval dispersal and potential colonization by

O. porrectus. Approaches integrating hydro-

dynamic and larval drift modeling, combined

with field sampling of early life stages, could

help test whether mesoscale eddies, coastal

upwelling relaxation, or current reversals pro-

mote cross-shelf connectivity between insular

and continental habitats (Ospina-Alvarez et al.,

2020). Additionally, targeted surveys along the

continental shelf, especially in areas influenced

by upwelling or strong eddy activity, would help

assess the spatial extent of the species’ distribu-

tion (Abernathey & Haller, 2018; Briones-Men-

doza et al., 2022). Given that this record is based

on a single specimen and the identification

relies exclusively on morphological evidence,

6Revista de Biología Tropical, ISSN: 2215-2075 Vol. 74 (S3): e20267102, abril 2026 (Publicado Abr. 24, 2026)

future efforts should prioritize the acquisition

and publication of molecular data to gener-

ate reference sequences, thereby promoting,

facilitating, and strengthening phylogeographic

assessments within the genus Ogcocephalus

and the Ogcocephalidae. Addressing sampling

biases using standardized trawls, baited remote

underwater video systems, and fine-mesh ben-

thic sleds will also be essential to detect cryp-

tic taxa and improve inventory completeness.

Finally, species distribution models incorporat-

ing environmental and oceanographic variables

could be used to predict potential ranges under

present and future climatic scenarios, offering

Fig. 2. Preserved specimen of Ogcocephalus porrectus from coastal waters of Costa Rica (UCR 3368-001), showing dorsal (A),

lateral (B), and ventral (C) views.

Revista de Biología Tropical, ISSN: 2215-2075, Vol. 74 (S2): e20267102, abril 2026 (Publicado Abr. 24, 2026)

valuable insights into the resilience and dis-

persal dynamics of benthic fishes in the ETP

(Ospina-Alvarez et al., 2020).

Author contribution statement: AA and

NVV-Q conceived, designed, and proposed the

study, and participated in the collection of the

specimen. AJD-M recorded the data from the

preserved specimen and comparative material.

All authors (AA, AJD-M, and NVV-Q) contrib-

uted to the analysis and interpretation of the

data, and to the preparation of the manuscript.

Ethics statement: The authors declare that

they all agree with this publication and that

they have made contributions that justify their

authorship; that there is no conflict of interest

of any kind; and that they have complied with

all relevant ethical and legal requirements and

procedures. All sources of funding are fully and

clearly detailed in the acknowledgements sec-

tion. The respective signed legal document is in

the journal’s archives.

ACKNOWLEDGMENTS

We thank Jorge Cortés, Frank Joyce, and

Jeffrey Sibaja for their roles in the conceptual-

ization, administration, and funding acquisi-

tion that made this research possible. We also

thank Freddy Lara, Frank Lara and Frank

Joyce for providing us with the boat to carry

out the fish sampling, and to Gabryele Mal-

cher, Pablo Rojas and Gilbert Ampie for their

assistance in the field, particularly during the

collection of the specimen. Pablo Rojas pro-

vided laboratory support for data acquisition

and specimen processing/cataloging. Research/

collection permits were issued by the Sistema

Nacional de Áreas de Conservación (SINAC;

R-SINAC-ACG-PI-051-2022).

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