New species of Leptocaris and a new record of Darcythompsonia inopinata (Harpacticoida: Darcythompsoniidae) from Colombia

Water samples taken from Rodadero Bay (Colombia) yielded three species of harpacticoid copepods of the family Darcythompsoniidae. Leptocaris colombiana sp. nov. is attributed to the brevicornis-group, and is characterized by the five-segmented antennule, discrete (not fused) female genital somite and third urosomite, six setae on the caudal rami, two setae on the antennal exopod, lack of abexopodal seta on the allobasis of the antenna, mandibular palp reduced to one seta, one inner seta only on the first endopodal segment of leg one and second segment with two apical elements, and by three setae on leg five. Leptocaris vicina sp. nov., is attributed to the mangalis-group, and is similar to L. stromatolicola in the armature formula of leg one to leg four, female leg five with two inner small subequal setae and one outer long element, five-segmented female antennule, antenna with one abexopodal seta on allobasis, antennal exopod reduced to two setae, mandibular palp reduced to one seta, and maxilla with two endites. These two species can be separated by the shape of the anal operculum, by the relative length of the endopodal segments of legs two and three, and by the innermost distal spine of the endopodal segment of the antenna. The record of Darcythompsonia inopinata from northern Colombia represents a continuum along the Caribbean coast of the Pacific dominion, Brazilian subregion.


INTRODUCTION
The marine and brackish harpacticoid fauna from Colombia has received some attention recently, and 15 families, 28 genera, and 48 species of harpacticoid copepods are known (Fuentes-Reinés and Zoppi de Roa 2013a, b, Fuentes-Reinés and Gómez 2014, Fuentes-Reinés and Suárez-Morales 2014a, b, Fuentes-Reinés et al. 2015, Gómez and Fuentes-Reinés 2017, Suárez-Morales and Fuentes-Reinés 2015a, b), including the three representatives of the family Darcythompsoniidae reported herein.Although they are common inhabitants of mangrove ecosystems (Por 1983, Gee and Somerfield 1997, Boxshall and Halsey 2004, Huys et al. 2016), members of the family Darcythompsoniidae are also common in some other habitats (Zamudio-Valdéz andReid 1990, Fiers 1986).Several harpacticoid copepods were gathered in water samples taken from mangrove ecosystems and oyster banks in Rodadero Bay, Magdalena, northern Colombia.Among others, we found specimens of Tisbintra (Tisbidae) and Geehydrosoma (Cletodidae), whose descriptions were published earlier (Gómez and Fuentes-Reinés 2017).Darcythompsoniids were scarce and only three specimens were retrieved.Two of them attributed to the genus Leptocaris and whose complete descriptions are given below, turned out to be new to science.Additionally, we report on the presence of Darcythompsonia inopinata Smirnov, 1934 in Rodadero Bay, Magdalena, northern Colombia.

MATERIALS AND METHODS
Eleven water samples were collected from mangrove ecosystems and at an oyster bank in Rodadero Bay, Magdalena, northern Colombia (11°14' North, 74°12' West).These samples were collected monthly from August 2015 to June 2016.Samples of 432 l each were taken using a 25 l bucket, sieved with a 45 µm zooplankton net, and preserved in 70% ethanol.Water salinity, pH, and temperature were measured with a Multi 350i handheld meter.Copepods were sorted manually and processed for taxonomic identification.Observations and drawings of the material presented herein were made from whole and dissected material.Dissected parts were mounted in lactophenol under a Leica compound microscope equipped with phase contrast and a drawing tube at a magnification of 1000X.Partially dissected material -habitus, right antennule, labrum, and P5 of Leptocaris colombiana sp.nov.was left intact and preserved in alcohol.
The material examined was deposited in the Copepoda collection of the Instituto de Ciencias del Mar y Limnología, Mazatlán Marine Station (ICML-EMUCOP) and in the Centro de Colecciones Biológicas de la Universidad del Magdalena-Colombia (CBUMAG).Morphological terminology follows 0 except for the maxilla.Morphological terminology for the latter follows Ferrari and Ivanenko (2008).The following abbreviations are used throughout the text and figures: ae, aesthetasc; P1-P4 ENP/EXP1-3, first (proximal) to third (distal) endopodal/exopodal segment of first to fourth leg; P5, fifth leg.
Note also that the genus name Leptocaris is feminine (Art.30.1.2;ICZN 1999) and Apostolov's (2007) and Huys ' (2009) views have been adopted here for the masculine del endópodo de la antena.Finalmente, el registro de Darcythompsonia inopinata en el norte de Colombia representa un continuo a lo largo de la costa caribeña del dominio del Pacífico, subregión Brasileña.Caribe, Copepoda, Crustacea, taxonomía.names given to some species of the genus.The biogeographical regionalization of the Neotropical region by Morrone (2014) was adopted.

Diagnosis
Habitus elongate, cylindrical.Rostrum minute.Female antennule five-segmented.Antenna with allobasis, without abexopodal seta; exopod represented by two setae; endopod one-segmented, with seven elements, of which apical inner spine smallest.Mandible with well-developed coxa and gnathobase; palpus represented by single seta.Maxillule with well-developed arthrite bearing four distal multicuspidate spines and three pinnate setae, and one surface seta; coxal endite, basis, exopod and endopod fused, with seven setae in all.Syncoxa of maxilla with one (probably coxal) endite armed with one stout spinulose element fused to endite basally, and one slender seta; allobasis with one (probably basal) strong claw with one accompanying seta, drawn out into strong curved claw with one accompanying seta (probably endopodal), endopod represented by two setae.Maxilliped absent.P1-P4 with threesegmented exopod and two-segmented endopod.Female P5 reduced, fused to somite ventrally, with three setae in all.Caudal rami with six setae.

Description of female
Habitus elongate, cylindrical, without a clear division between pro-and urosome.Total body length measured from anterior margin of rostrum to posterior margin of caudal rami, 620 µm.Cephalothorax (Fig. 1a) rounded anteriorly; with minute surface denticles posteriorly; with sensilla as shown; medial and posterior sensilla very long (indicated in Fig. 1a).Rostrum (Fig. 1a) minute, fused to cephalothorax, with two long sensilla.Surface of free prosomites (Fig. 1b) covered with small denticles; posterior margin of somites with coarser denticles and with some short sensilla; with two dorsal and two lateral long sensilla on posterior third of somites.First urosomite (P5-bearing somite; Fig. 1c) ornamented with denticles dorsally as previous prosomites; ventrally without denticles, with some sensilla along posterior margin only, with two small medial pores close to P5 (Fig. 1d).Genital somite and third urosomite discrete (Figs.1c, d); genital somite with small denticles dorsally, posterior denticles not coarser than the rest (Fig. 1c); ventrally without denticles, with some sensilla along posterior margin only (Fig. 1d); genital field (Figs.1d, f) located on anterior half of somite, with medial copulatory pore.Third urosomite with denticles and sensilla as in P5-bearing somite dorsally (Fig. 1c); ventrally with one row of slender spinules on proximal third, with one medial short row of slender spinules close to posterior margin, and one long row of slender spinules along posterior margin medially (Fig. 1d).Fourth urosomite as previous somite dorsally (Fig. 1c); ventrally without denticles, with long medial row of slender spinules along posterior margin (Fig. 1d).Fifth urosomite with small denticles dorsally, those along posterior margin not visibly coarser than the rest (Fig. 1c); without ventral ornamentation (Fig. 1d).Anal somite (Figs.1c-e) elongate, conical, tapering distally, about as long as two previous somites combined; with crescentic anal operculum not reaching posterior margin of somite (Fig. 1e); the two sensilla associated to the anal operculum separated by a gap visibly wider than the width of the anal operculum, and displaced medially (Figs.1c, e).Caudal rami (Figs.1c-e) ovate, about twice as long as wide; with six setae as follows (seta I lost): seta II and III vestigial, situated laterally on distal half of ramus; seta IV well-developed, displaced dorsally close to vestigial setae II and III; apical seta V longest; inner seta VI arising distally; dorsal seta VII arising medially, articulated basally.
Mandible (Fig. 2c) with well-developed gnathobase bearing several multicuspidate teeth and one lateral seta.Palp represented by one long seta.
Maxilliped absent.P1 (Fig. 3a).Coxa seemingly without ornamentation.Basis with one subdistal spinular row medially, and one transverse spinular row close to exopod, with one inner spine-like element and one outer seta.Exopod three-segmented; all segments with outer spinules close to outer spine and distally; EXP1 and EXP2 without inner seta; EXP3 with one outer spine, two apical and one inner bare elements; all elements seemingly bare.Endopod two-segmented; reaching distal margin of EXP2; ENP1 with some subdistal spinules, with one inner seta oriented downwards and with comb-like tip; ENP2 with some subdistal spinules, with one apical outer bare spine and one apical inner bare short seta.P2 (Fig. 3b).Coxa with some small spinules close to outer corner.Basis with one subdistal spinular row medially, and one transverse spinular row close to exopod; outer seta short, spine-like.Exopod three-segmented; all segments with outer spinules close to outer bare spine and distally; EXP1 and EXP2 without inner armature; EXP3 with two outer bare spines and two apical setae -outermost with outer spinules, innermost with outer spinules and inner setules-.Endopod two-segmented, barely reaching tip of EXP2, with spinular ornamentation as shown; ENP1 without armature; ENP2 with one strong inner seta with comb-like tip, two apical setae with outer spinules medially and with setules distally and along inner margin, and one outer apical bare spine.d).Coxa with some small spinules close to outer corner.Basis with one subdistal spinular row medially, and one transverse spinular row close to exopod; outer element setiform, longer than in P2.Exopod three-segmented; all segments with outer spinules close to outer bare spine and distally; EXP1 and EXP2 without inner armature; EXP3 with two outer bare spines, two apical setae with outer spinules and inner setules, and one inner plumose element.Endopod two-segmented, barely reaching tip of EXP2, with spinular ornamentation as shown; ENP1 without armature; ENP2 with one strong inner seta with comb-like tip, two apical setae with outer spinules medially and with setules distally and along inner margin, and one outer apical bare spine.Armature formula of P1-P4 as in table 1. P5 (Figs. 1d,f) represented by small segment fused to somite ventrally; each leg with three bare setae, of which innermost and outermost subequal in length, medial shorter.

Etymology
The specific epithet, colombiana, refers to the country where the species was found.
Antenna (Fig. 5b) with allobasis, the latter with abexopodal seta with comb-like tip, and about as long as free endopodal segment.Exopod represented by two setae.Endopodal segment with one proximal and one subdistal transverse row of strong spinules, with two stout lateral spines on inner margin, distally with three spines (innermost small and can be mistaken for spinule, arrowed in Fig. 5b), and two setae, one of them with comb-like tip.
Mandible as in previous species.
Maxillule (Fig. 5c) similar to that of L. stromatolicola, with four distal spines and two pinnate setae on well-developed arthrite, and one surface seta.Coxal endite, basis, exopod and endopod fused, with two lateral and two distal setae.Maxilla (Fig. 5d) with one syncoxal (probably coxal) endite with one stout spinulose element fused to endite basally, and seemingly two slender setae.Allobasis with one (probably basal) strong claw with two accompanying setae, drawn out into strong curved pinnate claw with one accompanying seta (probably endopodal), endopod represented by two setae.
Maxilliped absent.P1 (Fig. 6a, b).Coxa with posterior row of small spinules close to basis.Basis with one subdistal spinular row medially, and one transverse spinular row close to exopod, with one inner spine-like element and one minute outer seta (the latter arrowed in Fig. 6a,  b).Exopod three-segmented; all segments ornamented with subdistal and distal outer spinules; EXP1 and EXP2 without inner  seta; EXP3 with two outer pinnate spines and two bare distal setae.Endopod onesegmented; reaching middle of EXP2, with stout spinules medially and subdistally, with one inner seta oriented downwards and with comb-like tip, distally with one inner small seta and one outer apical pinnate spine, the latter twice as long as the former.P2 (Fig. 6c).Coxa with some posterior spinules close to outer corner.Basis with transverse row of small spinules close to exopod, and with minute spinules close to endopod, outer seta small.Exopod threesegmented; all exopodal segments with few distal and subdistal outer spinules; EXP1 and EXP2 without inner armature; EXP3 with two outer pinnate spines and two long apical setae with outer spinules and inner setules.Endopod two-segmented, reaching middle of EXP2; ENP1 about 1.8 times as long as ENP2, reaching beyond EXP1, with spinular ornamentation as shown and with one inner seta oriented downwards and with comb-like tip; ENP2 with some outer subapical spinules, distally with one outer small seta, two long setae with outer spinules and inner setules, and one inner seta with with comb-like tip.
P3-P4 (Figs. 6d, e).Coxa with some posterior spinules close to outer corner.Basis with transverse row of small spinules close to exopod, and with minute spinules close to endopod, outer seta well-developed, long.Exopod three-segmented; all exopodal segments with outer spinules as depicted; EXP1 and EXP2 without inner armature; EXP3 with two outer pinnate spines, two distal setae with outer spinules and inner setules, and one inner plumose element.Endopod two-segmented; ENP1 reaching tip of EXP1, about twice as long as ENP2, with some minute spinules apically, without armature; ENP2 reaching middle of EXP2, with one slender outer spine, two apical long setae and one inner element with comb-like tip.Armature formula of P1-P4 as in table 2. P5 (Fig. 6f) represented by small segment fused to somite ventrally; each leg with three bare setae, two innermost setae subequal in length, outermost longest.

Etymology
The specific epithet, vicina, from Latin vicinus, -a, -um, neighbor, makes reference to the fact that these two species were found in the same sample.

DISCUSSION
The marine and brackish harpacticoid fauna from Colombia is poorly known and have received some attention recently (e.g., Fuentes-Reinés and Zoppi de Roa 2013a, b, Fuentes-Reinés and Gómez  Reid (1990) and Fiers (1986) noted that some genera of this family, e.g.Leptocaris and Darcythompsonia, are common inhabitants of places completely different to mangrove systems.
The genus Leptocaris contains 29 species (L.trisetosus (Kunz, 1935) and L. echinata Fiers, 1986 with three and two subspecies, respectively), of which 12 species (L. trisetosa and L. echinata with one subspecies each; L. trisetosa trisetosa (Kunz, 1935), L. echinata echinata Fiers, 1986, L. armata Lang, 1965, L. brevicornis (Douwe, 1904) Kunz's (1978Kunz's ( , 1983Kunz's ( , 1994) ) species-groups, and Apostolov's (2007) reduction of speciesgroups from four as in Kunz (1994) to three.Fiers (1986; but see also Kunz 1994: 51) questioned the adequacy of the subdivision of the genus given the wide combination of characteristics in, for example, L. echinata echinata, and the wide variability in the general structure and armature complements of the antennal exopod, mandibular palp, presence/absence of an abexopodal seta in the antenna, fused/discrete condition of the female genital somite and third urosomite, and general structure of the maxilla, to name a few, within each species-group.Kunz's (1978Kunz's ( , 1983Kunz's ( , 1994) and Apostolov's (2007) subdivision of the genus are followed here for identification purposes only.However, as for many other species within the genus, the males of L. colombiana sp.nov.and L. vicina sp.nov.remain unknown, and the comparisons below are based solely on the females.The lack of males (see Lee and Chang 2008) and the wide variability observed in the number and shape of the setae on the female P5, among others, prevent any phylogenetical analysis (Fleeger and Clark 1980, Fiers 1986, Apostolov 2007).
The brevicornis-group, as defined by Kunz (1983Kunz ( , 1994) ) Kunz (1994).The abexopodal seta on the allobasis of the antenna is present in L. vermiculata, L. trisetosa pacifica, L. sibirica, both subspecies of L. echinata, and in L. mucronata.This seta is absent in L. colombiana sp.nov., L. gurneyi, and in L. trisetosa trisetosa and L. trisetosa breviseta, and its presence/absence needs to be verified for L. brevicornis and L. itoi.Gurney (1920) redescribed L. brevicornis from several situations in the Norfolk Broads without abexopodal seta on the allobasis of the antenna, but noted also that one specimen bore a "blunt-pointed seta" on the allobasis of both antennae; Lee and Chang (2008) described their L. brevicornis from South Korea without abexopodal seta on the allobasis of the antenna; the antenna of L. itoi was not described in Kunz (1994)

REMARKS
Currently, there are four valid species within Darcythompsonia (D. inopinata, D. neglecta Redeke, 1953, D. fairliensis, andD. scotti Gurney, 1920).D. inopinata is the most widespread (Fiers 1986, Gómez 2000) and has been reported previously from Fiji Islands, Western Samoa, Papua New Guinea, Grand Comores Archipelago, and Solomon Islands (Fiers 1986 and references cited therein).This species is known also from the Neotropical Region and has been reported from Inagua (Bahamas), Aruba (Netherlands Antilles) (Fiers 1986) in the Antillean subregion, in Morocoy Peninsula (Venezuela) (Fiers 1986) and in the Cananéia Lagoon estuarine system (Brazil), Brazilian subregion (Por et al. 1984, Reid 1998).This is a benthic species occurring in shallow marine and brackish coastal waters (Reid 1998), but also has been reported from a variety of situations like wells, caves, shallow pools, cenotes, crabholes, and in coarse sand and shell debris (Fiers 1986).The present record of D. inopinata from northern Colombia represents a continuum along the Caribbean coast of the Pacific dominion (Brazilian subregion).The specimen from Colombia fits the diagnostic features of D. inopinata as described by Smirnov (1934) and resembles D. fairliensis in the armature formula of P1-P4, number of segments of antennule, and number of segments and setae on the antennal exopod.Nevertheless, they can be separated by the number of setae in the female P5 (three setae in D. inopinata, but four elements in D. fairliensis), and by the shape of the caudal rami (with angular extension in the proximal half in D. fairliensis, but without angular extension in D. inopinata).
Borutzky 1952).The condition of the antennal exopod also varies among the species of the brevicornis-group.Two setae representing the antennal exopod have been observed in L. brevicornis, in the three subspecies of L. trisetosa, in L. vermiculata, L. mucronata, and L. colombiana sp.nov.; one seta has been observed for L. sibirica, while L. gurneyi, and both subspecies of L. echinata lack the antennal exopod.The antenna of L. itoi was omitted in mucronata, L. itoi and L. colombiana sp.nov.; seven setae in L. trisetosa pacifica), number of segments of the female antennule (four segments in L. mucronata; five segments in L. brevicornis, L. trisetosa trisetosa, L. trisetosa breviseta, L. trisetosa pacifica, L. gurneyi, L. vermiculata, L. echinata echinata, L. echinata nuda, and L. colombiana sp.nov.; five or six segments in L. sibirica; seven segments in L. itoi), number of setae of the antennal exopod (without setae in L. gurneyi, L. echinata echinata and L. echinata nuda; with one seta in L. sibirica; with two setae in L. brevicornis, L. trisetosa trisetosa, L. trisetosa breviseta, L. trisetosa pacifica, L. vermiculata, L. mucronata, and L. colombiana sp.nov.), presence of the abexopodal seta of the antenna in L. vermiculata, L. echinata echinata, and L. colombiana sp.nov.; with two setae in L. trisetosa trisetosa, L. trisetosa pacifica, L. trisetosa breviseta, L. mucronata, and L. itoi), and armature formula of the endopod breviseta, and L. sibirica; three setae in L. trisetosa pacifica, L. echinata echinata, L. echinata nuda, L. mucronata, and L. colombiana sp.nov.; with four setae in L. vermiculata and L. itoi). in both subspecies of L. echinata, and in L. colombiana sp.nov.The caudal rami possess less than six setae in L. brevicornis, L. trisetosa trisetosa and L. trisetosa breviseta, L. gurneyi, and L. sibirica; six setae have segmented female antennule, and the general shape and armature of the antenna (allobasis with one abexopodal seta, exopod represented by two setae, endopodal segment with five spines and two setae), and mandible (palp represented by one seta).Furthermore, some striking similarities were observed between the general shape of the maxillule (arthrite with one surface seta, and with four spines and two pinnate setae distally), and the maxilla of L. stromatolicola and L. vicina sp.nov.Regarding the maxilla, besides the two setae representing the endopod, both species share the presence of two endites; the proximal endite of L. stromatolicola possesses one strong spinulose element only, while that of L. vicina sp.nov.possesses one strong spinulose element and two slender setae that are difficult to see and probably have been overlooked in L. stromatolicola; the second endite is armed with two slender setae and a curved strong element in both species.These two species can be separated by the shape of the anal operculum (crescentic in L. stromatolicola, but rounded in L. vicina sp.nov.), by the relative length of the segments of P2 ENP and P3 ENP (ENP1 visibly longer that ENP2 in L. vicina sp.nov., but nearly subequal in L. stromatolicola), and by the innermost distal spine of the endopodal segment of the antenna (reduced in L. vicina sp.nov., but well-developed in L. stromatolicola).