A new species of sand eel genus Bascanichthys (Anguilliformes: Ophichthidae) from the Caribbean

Abstract

A new species of the sand eel genus Bascanichthys (Anguilliformes: Ophichthidae) is described from specimens found inside the stomachs of mature female numbfish Narcine bancroftii. These rays were collected as bycatch in local fisheries, using beach seines in shallow waters (5 to 10 m) in Gaira Bay (Santa Marta, Colombian Caribbean). Bascanichthys gaira n.sp., is described from three specimens and can be distinguished from other species of the genus by its minute pectoral-fin base (12.3-24.7% of gill-opening length) and its vertebral number (189).

Full text

Instituto de Investigaciones Marinas y Costeras 7
Bol. Invest. Mar. Cost. 45 (1) ISSN 0122-9761 Santa Marta, Colombia, 2016
A NEW SPECIES OF SAND EEL GENUS BASCANICHTHYS
(ANGUILLIFORMES: OPHICHTHIDAE) FROM THE
CARIBBEAN
Fabián Moreno1, Arturo Acero P.2 and Marcela Grijalba-Bendeck3
1 Universidad Santo Tomás Villavicencio, Ciencias Básicas, Villavicencio, Colombia. fabianmorenor@
usantotomas.edu.co
2 Universidad Nacional de Colombia Sede Caribe, Cecimar, El Rodadero, Santa Marta, Colombia.
aacerop@unal.edu.co
3 Universidad de Bogotá Jorge Tadeo Lozano, Facultad de Ciencias Naturales e Ingeniería, Programa
de Biología Marina, Grupo de Investigación Dinámica y Manejo de Ecosistemas Marino Costeros
(DIMARCO), Mundo Marino, El Rodadero, Santa Marta, Colombia. marcela.grijalba@utadeo.edu.co
ABSTRACT
A new species of the sand eel genus Bascanichthys (Anguilliformes: Ophichthidae) is
described from specimens found inside the stomachs of mature female numbsh Narcine bancroftii.
These rays were collected as bycatch in local sheries, using beach seines in shallow waters (5 to 10 m)
in Gaira Bay (Santa Marta, Colombian Caribbean). Bascanichthys gaira n.sp., is described from three
specimens and can be distinguished from other species of the genus by its minute pectoral-n base (12.3-
24.7% of gill-opening length) and its vertebral number (189).
KEY WORDS: Endemic sand eel, Anguilliformes, Ophichthidae, Colombia, Southern Caribbean.
RESUMEN
Una nueva especie de anguila de arena del género Bascanichthys (Anguilliformes:
Ophichthidae) del Caribe. Nueva especie de anguila de arena del género Bascanichthys (Anguilliformes:
Ophichthidae) es descrita a partir de ejemplares encontrados en el contenido estomacal de hembras
maduras de la raya eléctrica Narcine bancroftii. Estas rayas fueron colectadas como parte del bycatch
en las pesquerías locales, usando chinchorros playeros en aguas superciales (5 a 10 m) de la bahía de
Gaira (Santa Marta, Caribe colombiano). Bascanichthys gaira sp. n. es descrita a partir de tres ejemplares
colectados y es fácilmente diferenciable de otras especies del mismo género debido a su diminuta aleta
pectoral (su base representa entre 12.3-24.7% de la longitud de la apertura branquial) y su número de
vértebras (189).
PALABRAS CLAVES: Anguila de arena endémica, Angulliformes, Ophichtidae, Colombia, Caribe sur.
7-14

8Boletín de Investigaciones Marinas y Costeras • Vol. 45 (1) • 2016
INTRODUCTION
Snake eels of the family Ophichthidae are the most diverse of true eels,
including 260 living species distributed among 58 genera in all tropical oceans and
seas (McCosker, 2002; Nelson, 2006). Snake eels live in a variety of habitats, from
sandy intertidal to midwater depths of 800 m (McCosker, 2002). Ophichthids have
pelagic leptocephalus larvae. The adults live in a variety of environments, from coral
reefs to sand and mud substrates, oceanic midwaters, and also in rivers and estuaries
(McCosker et al., 1989). Some species are taken as bycatch of several types of
sheries, using trawl sheries and hook-and-line, but they are rarely consumed
(McCosker, 2002).
According to McCosker et al. (1989), Ophichthidae is currently divided
into two subfamilies, Myrophinae (tribes Benthenchelyini and Myrophini) and
Ophichthinae (including the tribes Bascanichthyini, Callechelyini, Ophichthini, and
Sphagebranchini). The Bascanichthyini, sand eels, includes moderately small, very
elongate, plain-coloured or banded species with hanging pointed snouts and anus at
or behind the mid-body. They live buried in sand and mud from shallow to moderate
depths. Sand eels are collected using ichthyocides in shallow waters, but are also
captured by benthic and midwater trawling. The Bascanichthyini comprises eight
genera, but only ve are found in the western Atlantic, Bascanichthys, Caralophia,
Ethadophis, Gordiichthys, and Phaenomonas (McCosker et al., 1989).
The family Ophichthidae is poorly known in the Colombian Caribbean,
with only a few reports published, including Ichthyapus ophioneus (Evermann &
Marsh 1900), Callechelys bilinearis Kanazawa 1952 (Acero and Garzón, 1986),
and Ophichthus cylindroideus (Ranzani 1839) (Barrera-García et al., 2008). Species
of Bascanichthys, the most primitive member of its tribe, inhabit sand, mud and
silt bottoms; other features include an elongated body, cylindrical and compressed,
head and trunk longer than the tail, dorsal n originating on the head, median ns
low, pectoral ns small, snout short and rounded, standing over the lower jaw, jaws
short, eyes small, and anterior nostrils tubular (McCosker et al., 1989). Reaching a
maximum size of about 1000 mm total length, they are distributed in all tropical seas
with approximately 12 valid species, but only four are recognized in the western
Atlantic, Bascanichthys bascanium (Jordan 1884), Bascanichthys inopinatus
McCosker, Böhlke & Böhlke 1989, Bascanichthys paulensis Storey 1939, and
Bascanichthys scuticaris (Goode and Bean 1880). Herein we present the original
description of a new species of Bascanichthys based on three specimens obtained
from the stomachs of Narcine bancroftii (Grifth and Smith) shed in Gaira bay,
Colombian Caribbean.

Instituto de Investigaciones Marinas y Costeras 9
MATERIAL AND METHODS
Three sand eel specimens were found inside the stomachs of three mature
females (462 to 542 mm total length) of Bancroft’s numbsh Narcine bancroftii.
These rays were collected as bycatch in local sheries using beach seines in shallow
waters (5 to 10 m) at Gaira bay in Salguero beach, located toward south of Santa
Marta, Colombian Caribbean (11º10’11”N, 74º13’14”W). In the laboratory the
numbsh were dissected from the pectoral arch to the cloaca, their stomachs were
extracted and the contents deposited in a Petri box and then washed with fresh
water; afterward, the material was weighed with a digital scale and stored in 70%
isopropyl alcohol. The eels were almost perfectly conserved, keeping most of their
skin and coloration, thus digestion process had not damaged the main features of the
specimens. Both the holotype and paratypes were deposited in the sh collection of
the Marine Natural History Museum of the Marine and Coastal Research Institute
(Invemar) under the reference INV PEC8147 holotype, INV PEC8146 and INV
PEC8145 paratypes.
All counts and measurements were taken directly from specimens using a
calliper. Measurement values were recorded to the nearest tenth (0.1) of a millimetre,
following McCosker et al. (1989). The following measurements were taken: Total
length (TL), straight-line distance between the anterior tip of the upper lip and
posterior tip of the tail; head length (HL), straight-line distance between the anterior
tip of the upper lip and posterior edge of the opercular ap; trunk length, straight-line
distance from the posterior edge of the opercular ap to mid-anus; tail, straight-line
distance between mid-anus and rear tip of the tail; predorsal length, straight-line
distance from anterior tip of upper lip up to anterior margin of the dorsal n; depth
at gill opening, body depth behind the gill opening; gill opening length, straight-line
distance between gill opening corners; depth at anus, body depth at mid-anus; snout,
straight-line distance from anterior tip of upper lip to closest point on the anterior
eshy edge of the orbit; preanal length, straight-line distance from anterior tip of
the upper lip to mid-anus; eye, horizontal diameter of the eye; inter-orbital width,
straight-line distance between eyes; pectoral-n length, distance between base and
rear tip of the pectoral n; pectoral-n base, length of pectoral-n base.
Pore numbers were expressed as follows: supraorbital pores (SO) as
ethmoid pore + pores in supraorbital canal; infraorbital pores (IO) as pores along
upper jaw + pores in the vertical part of the canal behind the eye (in general the
last pore included along the upper jaw is considered one of the postorbital pores);
preoperculomandibular pores (POM) as pores along the lower jaw + preopercular
pores; supratemporal pores (STC) total number of pores in the supratemporal canal

10 Boletín de Investigaciones Marinas y Costeras • Vol. 45 (1) • 2016
(McCosker et al., 1989). One paratype was used to count total, predorsal, and preanal
vertebrae. All counts and measurements were compared with material of two species
of the genus Bascanichthys, B. inopinatus (ANSP 158886 paratype) and B. paulensis
(ANSP 156906, ANSP 158821 paratypes), and ve additional species recorded in
the bibliography from the western Atlantic and the Eastern Pacic coasts.
Bascanichthys gaira, new species
Figure 1, 2
Figure 1. Bascanichthys gaira n.sp., holotype. INV PEC8147, 477 mm TL, Gaira Bay, Santa Marta,
Colombia. Picture by A. Polanco, MHNM Invemar.
Material examined. Holotype, INV PEC8147 (477 mm TL), bahía de
Gaira, Santa Marta, Colombia (11º10’11” N, 74º13’14” W), September 5, 2005.
Paratypes, INV PEC8145 (468 mm TL) September 5, 2005, INV PEC8146 (411
mm TL) August 22, 2006, all from the same locality as the holotype: Bahía de Gaira,
Santa Marta, Colombia (11º10’11” N, 74º13’14” W).
Diagnosis. An elongate, markedly bicolored bascanichthyin, dark brown
dorsally and light brown almost cream ventrally, head and snout dark, ns pale
without marks, sex unrecognized. Maximum total length 477 mm. Proportions as
% of TL: head 4.6-5.3, trunk 47.9-51.7, tail 43.8-47.9; depth (at gill opening) 1.2-
1.5; depth (at anus) 1-1.1; predorsal length 2.1-2.4; snout 12.4-12.7; eye 4.1-5.5;

Instituto de Investigaciones Marinas y Costeras 11
Table 1. Proportional measurements (% TL) of Bascanichthys gaira n. sp.
interorbital width 6.9-9.7; pectoral-n length 6.4-7.0 mm; Pores SO 1 + 3, IO 4 +
2, POM 4 + 2, STC 3. Pectoral n minute, its base corresponding to 12.3-24.7% of
gill-opening length. Uniserial mandibular teeth (Table 1; Figure 2).
Measurements (mm) Holotype % Paratypes %
Total length 477 -468 411 - -
Head 21.8 4.6 21.3 21.7 4.6 5.3
Trunk 242 50.7 242 197 51.7 47.9
Preanal length 264 55.3 261 218 55.8 53
Tail 215 45.1 205 197 43.8 47.9
Predorsal length 10.9 2.3 9.8 9.8 2.1 2.4
Depth at gill opening 5.8 1.2 6.9 6.1 1.5 1.5
Depth at anus 5.1 1.1 5.2 4 1.1 1
Proportion of head length % %
Snout 2.7 12.5 2.7 2.7 12.7 12.4
Eye 0.9 4.1 1.1 1.2 5.2 5.5
Interorbital width 2.1 9.7 2 1.5 9.4 6.9
Left gill-opening length 1.5 6.9 1.5 1.5 76.9
Right gill-opening length 1.4 6.4 1.5 1.5 76.9
Left pectoral-n length 1.3 5.9 -1.1 -5.3
Right pectoral-n length 1.5 6.8 -1.1 -5.1
Length left pectoral-n base 0.2 0.8 -0.4 -1.7
Length right pectoral-n base 0.3 1.2 -0.3 -1.4
Proportion of gill-opening lengths % %
Left pectoral n -12.3 - - - 24.7
Right pectoral n -18.5 - - - 19.7
Description. Total vertebrae 189, predorsal vertebrae 1, preanal vertebrae
100. Elongate body, muscular and rounded, anus shortly behind midbody,
longitudinal folds on head and gular region (Figure 2). Median ns developed but
low, ending shortly before tail tip, pectoral n minute, its base one-fourth the length
of the gill openings, pectoral n moderately long for Bascanichthys (3 to 6 times the
length of its base), somewhat triangular and nishing in a lament. Head and jaws
short, pointed snout overhanging lower jaw, eye small, located above half of the
lower jaw, anterior nostril tubular, posterior nostril above midlength of upper jaw

12 Boletín de Investigaciones Marinas y Costeras • Vol. 45 (1) • 2016
and without ap, visible externally as a small hole in the upper lip. Head pores small
and well-dened (Figure 2). Gill openings moderate in size, vertical and low-lateral
on side, dentition typical for the genus, three anterior intermaxillary large stout teeth
describing an inverted “V” in a groove on the underside of the snout, exposed when
the mouth is closed, 13 to 17 teeth along vomer, well-separated from conical and
uniserial (13-14) intermaxillary and maxillary teeth.
Figure 2. A and C. Pictures of Bascanichthys gaira n. sp. holotype. INV PEC8147, 477 mm TL, Gaira
Bay, Santa Marta, Colombia. B and D. Drawings of head with well-developed pores: Supraorbital pores
(SO), infraorbital pores (IO), preoperculomandibular pores (POM) and supratemporal pores (STC).
Pictures by A. Polanco, MHNM Invemar and illustrations by F. Moreno.
Distribution. All the specimens were collected in Gaira Bay (11º10’11” N,
74º13’14” W), Santa Marta, Colombia, inside the stomach of mature females of Bancroft’s
numbsh Narcine bancroftii, shed as bycatch of the local beach seine sheries.
Etymology. This species was named gaira in reference to Bahía de Gaira,
where this species was captured. The proposed vernacular name “Colombian sand
eel” refers to the fact that this species is the rst record of the genus Bascanichthys
from Colombia and the southern Caribbean.
Remarks. Type material was compared with museum specimens of
B. inopinatus (ANSP 158886 paratype) and B. paulensis (ANSP 156906, ANSP
158821 paratypes) as well as with the descriptions of Neotropical species presented
by McCosker et al. (1989) and Robertson et al. (2015). There were four described

Instituto de Investigaciones Marinas y Costeras 13
species of Bascanichthys from the western Atlantic: B. bascanium (Jordan 1884),
B. inopinatus McCosker, Böhlke and Böhlke 1989, B. paulensis Storey 1939 and B.
scuticaris (Goode and Bean 1880). Bascanichthys scuticaris differs from the new
species by having a total of 159-167 vertebrae (vertebral count for B. gaira is 189).
Other diagnostic characters of B. scuticaris, a species taken at coastal United States
from North Carolina to the Gulf of Mexico, that differ from B. gaira are body marked
by a series of small, pale spots above each lateral-line pore along body, tail, and
branchial region; pore sequence: SO 1 + 3, IO 4 + 2, POM 4 + 2, ST 3 (McCosker et
al., 1989). Bascanichthys gaira differs from the other three western Atlantic species
(B. bascanium, B. inopinatus, and B. paulensis) because pectoral n in B. gaira is
minute, its base corresponds to 12.3-24.7% of gill-opening length. In B. bascanium,
a species reported from Georgia to Honduras, Puerto Rico, and a locality in Panamá,
pectoral n is broad-based and its width 44-47% length of gill opening (McCosker
et al., 1989); it should be corroborated if the material from Panamá indeed coincides
with B. bascanium or it agrees with the new species. In B. inopinatus, a species
apparently endemic to Puerto Rico, pectoral n base represents 36-37% of the length
of gill opening; additionally, B. gaira differs from B. inopinatus in vertebrae counts
(B. gaira has 189 total vertebrae, 1 predorsal vertebra, and 100 preanal vertebrae; B.
inopinatus has 199, 1, and 101, respectively) and in the number of supraorbital pores
(B. gaira has 1+3 SO, B. inopinatus 1+4 SO) (McCosker et al., 1989; Robertson
et al., 2015). Bascanichthys gaira seems to be closer to B. paulensis, since both
have similar vertebrae counts; in B. paulensis the total vertebrae range between 190
and 196, with one or two predorsal vertebrae and 100-103 preanal vertebrae. Pore
numbers are the same in both species. The pectoral n and base length are different;
in B. paulensis the pectoral-n base length range is between 25 and 33% of the gill-
opening length, while in B. gaira the pectoral n base ranges from 12.3 to 24.7%
of the gill-opening length. Bascanichthys paulensis has a very small and rounded
pectoral n, with a narrow base; although the pectoral n of B. gaira is smaller, it is
not rounded but somewhat triangular and nished in a lament.
In the Eastern Pacic B. gaira has three relatives: B. panamensis Meek and
Hildebrand 1923, B. cylindricus Meek and Hildebrand 1923, and B. bascanoides
Osburn and Nichols 1916 (Meek and Hildebrand, 1923). The main differences
between them are the total number of vertebrae (total vertebrae 189, predorsal
vertebrae 1, preanal vertebrae 100) and pectoral n base/length ratio (12.3-24.7% of
gill-opening length) (Tables 1 and 2).
Natural coloration of B. gaira is markedly bicolored, dark brown dorsally
and light brown almost cream ventrally, head and snout dark, ns pale without
marks. Colour in alcohol same that natural with some light zones in head and body.

14 Boletín de Investigaciones Marinas y Costeras • Vol. 45 (1) • 2016
ACKNOWLEDGEMENTS
To the Research Direction, the Marine Biology Program and the Facultad
de Ciencias Naturales e Ingeniería, Universidad de Bogotá Jorge Tadeo Lozano
for nancial support of the project “Biological aspects of some batoids from Santa
Marta, Colombian Caribbean” (315P). This is contribution 399 of the Instituto de
Estudios en Ciencias del Mar (Cecimar), Universidad Nacional de Colombia sede
Caribe.
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RECEIVED: 15/10/2014 ACCEPTED: 28/10/2015