Tanaella quintanai, a new deep-water tanaellid (Crustacea: Peracarida: Tanaidacea) from the Colombian Caribbean Coast, with a key to the species of the genus Tanaella Norman & Stebbing, 1886

Introduction

The Tanaidacean fauna from Colombia has received minimal attention thus far. Recently, Morales-Núñez & Ardila (2018) reported the first record for the family Tanaellidae Larsen & Wilson, 2002 in the Colombian Caribbean region. In addition, Morales-Núñez, Morales-Ruiz & Ardila (2017) described a new sphyrapodid tanaidacean, Sphyrapus caribensis Morales-Núñez, Morales-Ruiz & Ardila, 2017, reported Kudinopasternakia siegi (Viskup & Heard, 1989), and presented detailed information about the species of tanaidaceans that had been previously reported in the Caribbean and Pacific Colombian coasts.

This publication is the second in a series dealing with the Tanaidacea from the Colombian Caribbean region, and it presents a description of a new species of Tanaella Norman & Stebbing, 1886.

The family Tanaellidae was established by Larsen & Wilson (2002) and currently contains five genera (i.e., Araphura Bird & Holdich, 1984; Arhaphuroides Sieg, 1986; Arthrura Kudinova-Pasternak, 1966; Inconnivus Błażewicz-Paszkowycz & Bamber, 2012; and Tanaella Norman & Stebbing, 1886). An examination of tanaidaceans collected during explorations along the outer shelf, continental slope, and continental margin of the Caribbean coast of Colombia during cruises in 2014–2015, revealed the presence of an apparently undescribed species belonging to the tanaellid genus Tanaella. The genus was originally erected by Norman & Stebbing (1886) to receive the new species T. unguicillata Norman & Stebbing, 1886. Tanaella has a cosmopolitan distribution and is recorded over a wide bathymetric range, from shallow waters (38 m) down to abyssal depths (5,450 m) (Guerrero-Kommritz & Błażewicz-Paszkowycz, 2004; Larsen & Heard, 2004; Drumm & Bird, 2016).

Materials & Methods

Specimens were collected using a box corer of 0.25 m² during cruises, aboard the R/V Proteus and R/V Don Rodrigo-B, working off the southwestern Caribbean Sea of Colombia at depths of 1,598–2,821 m (Fig. 1). Tanaidaceans were sorted, fixed in 6% formalin, and subsequently stored in 70% ethanol. Collection permits were granted by the National Authority of Environmental Licenses—ANLA (FSD, ANLA No. 0723 de 2012; FND, ANLA 1016 de 2012; PAC, ANLA No. 0880 de 2014).

Specimens were dissected under an Olympus SXZ-16 stereomicroscope. Appendages were mounted on glass slides in glycerine and observed with an Olympus BX41 microscope, and drawings were made with a camera lucida. Illustrations were prepared with Adobe Illustrator CC (2019) and figures with Photoshop CC (2019). Photographs were taken using an Olympus DP73 digital camera mounted on a stereomicroscope and all specimens were measured with CellSens Dimension 1.11 Imaging Software (Olympus). Maps were created using ArcGIS 10.4.1 software (University of Maryland Eastern Shore (UMES)).

All specimens of Tanaella sp. were measured and classified into two life-stages categories (Table 1).

Type material has been deposited in the “Centro de Colecciones Biológicas, Universidad del Magdalena (CBUMAG)”, Santa Marta, Colombia. All measurements were taken in millimeters (mm). Total body length was measured from the tip of the rostrum to the tip of the pleotelson. Terminology generally follows that of Larsen (2003); however, the term “PSS” is here applied for delicate plumose sensory setae found on antennules, antennae, pereopods and uropods (Bird, 2011).

The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Commission on Zoological Nomenclature (ICZN), and hence the new names contained in the electronic version are effectively published under that Code from the electronic edition alone. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix http://zoobank.org/. The LSID for this publication is: [urn:lsid:zoobank.org:pub:BB577909-6C9F-4008-AA2D-2330525FAACE]. The online version of this work is archived and available from the following digital repositories: PeerJ, PubMed Central and CLOCKSS.

Systematics

Diagnosis. See Larsen (2005).

Type-species. Tanaella unguicillata Norman & Stebbing, 1886

Species. Tanaella busteri Drumm & Bird, 2016; T. dongo Bamber, 2005; T. eltaninae Guerrero-Kommritz & Błażewicz-Paszkowycz, 2004; T. forcifera (Lang, 1968); T. kimi Guerrero-Kommritz & Błażewicz-Paszkowycz, 2004; T. kommritzia Larsen & Shimomura, 2007; T. kroyeri Larsen, Araújo-Silva & Coelho, 2009; T. mclellandi Larsen & Heard, 2004; T. ochracea Hansen, 1913; T. paraforcifera (Lang, 1968); T. profunda Guerrero-Kommritz & Błażewicz-Paszkowycz, 2004; T. prolixcauda Larsen & Heard, 2004; T. propinquus Dojiri & Sieg, 1997; T. quintanai sp. nov.; T. rotundicephala Sieg, 1986; T. tuberculata Kudinova-Pasternak, 1989; T. unguicillata Norman & Stebbing, 1886; T. unisetosa Sieg, 1986.

Amended diagnosis. Female. Uropod shorter than pleotelson

Remarks. In the original description of Tanaella eltaninae, Guerrero-Kommritz & Błażewicz-Paszkowycz (2004) stated that this species has an “Uropod as long as pleotelson” (p. 3; diagnosis section). However, as it can be observed in the original illustration (p. 4; figs. 1A–1B), the female has an uropod shorter than pleotelson i.e., uropod about 2/3 as long as pleotelson, instead of the uropod being as long as the pleotelson.

Amended diagnosis. Male and Female. Uropod shorter than pleotelson

Remarks. In the original description of Tanaella kimi, Guerrero-Kommritz & Błażewicz-Paszkowycz (2004) stated that this species has an “Uropod as long as pleotelson” (p. 8; diagnosis section), which was based on a male (holotype). However, as it can be observed in the original illustrations of a male (p. 9; figs. 4A–4B) and female (p. 9; fig. 4F), the male and female have an uropod shorter than pleotelson i.e., uropod about 2/3 as long as pleotelson, instead of the uropod being as long as pleotelson.

Synonyms: Tanaella sp. Morales-Núñez & Ardila, 2018

Material examined. Holotype—non-ovigerous ♀ (CBUMAG:MAC:01679), TL 2.6 mm, Station (Stn) E05PAC (9°14′3.8″N–76°47′14.57″W), depth 1,598 m, substrata: “muddy bottom”, 27-July-2014.

Paratypes—Non-ovigerous ♀ (dissected) (CBUMAG:MAC:01681), TL 2.3 mm, Stn E15PAC (10°22′0.2″N–76°27′5.17″W), depth 2,821 m, substrata: “muddy bottom”, 26-July-2014.—Non-ovigerous ♀ (CBUMAG:MAC:01680), TL 2.2 mm, Stn E04FND (10°26′55.54″N–76°15′25.29″W), depth 2,258 m, substrata: “muddy bottom”, 09-October-2015.—Non-ovigerous ♀ (damaged) (CBUMAG:MAC:01683), TL 2.4 mm, Stn E06FSD (9°10′1.14″N–76°50′10.18″W), depth 1,659 m, substrata: “muddy bottom”, 25-April-2015. —♀ with marsupium (CBUMAG:MAC:01682), TL 2.2 mm, Stn E13PAC (10°08′59.42″N–76°32′48.77″W), depth 2,423 m, substrata: “muddy bottom”, 26-July-2014.

Diagnosis. Female. Pleotelson as long as pleonites 1–5 combined. Antenna article-3 with fusion line. Labium with apical lobe bearing one blunt seta. Cheliped dactylus without process and with sub-proximal bipinnate seta on inner face. Pereopods 1–3 with basis having sub-dorsoproximal and sub-ventroproximal margins setulose. Pereopods 4–6 with basis having ventroproximal margin setulose and unguis bearing two parallel rows of small setules. Pleopods absent. Uropod shorter than pleotelson, basal article less than half length of endopod.

Etymology. Named in honor of renowned Colombian racing cyclist Nairo Alexander Quintana Rojas, in recognition and appreciation for his outstanding effort and dedication, as well as for bringing pride and happiness to the Colombian nation.

Type locality. Offshore waters of Córdoba department (9°14′3.8″N–76°47′14.57″W), Colombia, South America.

Distribution. Colombian Caribbean at depths ranging from 1,598 to 2,821 m.

Description. Based on non-ovigerous ♀.

Body (Fig. 2A). Fairly slender, TL 2.3 mm, about 6.6 times as long as wide.

Cephalothorax (Fig. 2A). About 21% of TL, shorter than combined lengths of pereonites 1–3, 1.4 times longer than wide, oval shape, asetose; anterior margin with rounded rostrum.

Pereon (Fig. 2A). About 54% of TL, all pereonites wider than long; pereonites 1 and 6 shorter than other pereonites; pereonites 2–5 increasing in length, being pereonite-5 the longest.

Pleonites (Figs. 2A–2B). About 12% of TL, combined lengths of pleonites 1–5 about same length that of pereonite-5, all pleonites sub-equal in length, wider than long, lacking pleopods; all pleonites laterally rounded (Fig. 2B); pleonite-5 with one pair of small lateral setae.

Pleotelson (Figs. 2A–2B). About 13% of TL, sub-equal length that of pleonites 1–5 combined, asetose; apex rounded.

Antennule (Figs. 3A–3B). Slightly shorter than cephalothorax, with four articles. Article-1 longer than combined length of articles 2–4, about three times as long as wide; ventral margin with sub-distal very finely bipinnate seta (Fig. 3B); dorsal proximal margin with setules; inner ventral margin with two (one horizontal and one oblique) sub-distal rows (six and three, respectively) of PSS. Article-2 about 1.8 times as long as wide; ventral margin with sub-distal long very finely bipinnate seta; inner ventral margin with sub-distal oblique row of four PSS. Article-3 about five times wider than long; distoventral margin setulose; mid margin with very finely bipinnate seta; sub-distal dorsal margin with very finely bipinnate seta. Article-4 length almost half of article-2, about 2.5 times as long as wide; distal margin with five (i.e., four simple, possibly very finely bipinnate, and one very finely bipinnate) setae of unequal lengths; sub-distal dorsal margin with simple seta.

Antenna (Fig. 3C). With five articles (article-3 with fusion line). Article-1 broader than following articles; outer mid distal margin with simple seta; anterior dorsal half margin with several rows of setules and distodorsal very finely bipinnate seta; inner mid ventral margin with oblique of setules. Article-2 shorter than article-1, sub-quadrate, with distodorsal very finely bipinnate seta. Article-3 longer than other articles, with clear fusion line; distoventral margin with one small simple seta and two long very finely bipinnate setae; mid sub-distal outer margin with simple seta; posterior dorsal half margin with several rows of setules; inner margin with one mid PSS and distal oblique row of three PSS. Article-4 longer than article-2, about 2.4 times as long as wide; inner distal margin with mid long very finely bipinnate seta. Article-5 minute, with distal margin bearing four (i.e., three simple (possibly very finely bipinnate) and one very finely bipinnate) setae of unequal lengths.

Mouthparts: Labrum (Fig. 3D) hood-shape and finely setose. Mandibles (Figs. 3E–3G): left mandible, with incisor with three uneven denticles, lacinia mobilis long, narrow (Fig. 3E). Right mandible incisor with three uneven denticles (Fig. 3F). Molar process of left and right mandibles similar, broad and blunt, with four apical denticles and three rectangular bifurcated seta (Fig. 3G).

Labium (Figs. 3H–3I). Two triangular lobes, each lobe with inner and distal margin setulose, apical lobe with one blunt seta (Fig. 3I).

Maxillule (Figs. 4A–4B). Endite with seven distal spiniform setae (two pectinate; Fig. 4B), outer distal margin with several setules; palp bearing two long terminal setae of unequal lengths.

Maxilla (Fig. 4C). Elongate subovate.

Maxilliped (Figs. 4D–4E). Basis fused, setose, each with very finely bipinnate seta near palp insertion. Endites with distal process and two pairs of very finely bipinnate setae of unequal lengths; outer margin with oblique row of setules (Fig. 4E). Palp article-1 with several rows of setules; article-2 with several rows of setules, inner distal margin with two simple setae and one very finely bipinnate seta (Fig. 4D), outer margin with simple seta; article-3 with inner margin having four setae (two very finely bipinnate and two simple) of unequal lengths (Fig. 4D), mid margin with oblique row of setules, outer margin with several rows of setulate; article-4 with distal margin bearing four setae (two very finely bipinnate and two simple) (Fig. 4D), mid margin with sub-distal simple seta and oblique row of setules (Fig. 4D), outer margin with sub-distal simple seta (Fig. 4D).

Epignath. Not recovered.

Cheliped (Figs. 5A–5F). Basis length subequal to carpus, about 1.7 times as long as wide, posterior lobe larger than anterior mass, with sub-distal dorsal seta on outer margin (Fig. 5A). Merus triangular with simple seta on mid ventral margin. Carpus about 1.4 times as long as wide; mid ventral margin with two simple setae; dorsal margin with two (one proximal and one distal) small simple setae. Propodus as long as wide, with distodorsal simple seta (Fig. 5B), palm 1.4 times longer than fixed finger, outer margin with simple seta near to insertion of dactylus, inner face with five bipinnate setae (one distinctly longest) near to articulation of dactylus (Figs. 5E–5F); fixed finger with two ventral setae, with three sub-marginal simple setae on outer incisive margin, cutting edge with proximal serrated depression (Figs. 5A–5C) and five (three rounded and two sharp) denticles (Fig. 5C), claw short. Dactylus and unguis curving downward; ventral margin with two small blade-like pectinate setae (Fig. 5D); inner face with bipinnate seta on sub-proximal margin (Fig. 5E).

Pereopod-1 (Figs. 6A–6C). Coxa with simple seta on anterodistal margin. Basis as long as combined length of ischium, merus, carpus, and half of propodus, about six times as long as wide; sub-ventroproximal margin setulose; sub-dorsoproximal margin setulose with one PSS. Ischium wider than long, with one simple seta on ventral margin. Merus slightly shorter than carpus, about 2.2 time as long as wide; distoventral margin with bipinnate seta (Fig. 6B); inner margin with sub-distal simple seta. Carpus about two times as long as wide; distoventral margin with bipinnate seta; distodorsal margin with bipinnate seta, inner margin with mid sub-distal bipinnate seta. Propodus about four times as long as wide; ventral margin with two (one on inner view (Fig. 6C)) rows of spinules and one distal spiniform seta (possibly bipinnate); dorsal margin with a row of setules (Fig. 6A) and distally with spine-like apophysis; inner face with sub-distal dorsal simple seta and distally setose (Fig. 6C). Dactylus together with unguis shorter than propodus; dactylus slightly longer than unguis.

Pereopod-2 (Figs. 6D–6E). Similar to pereopod-1 except: shorter; basis with two PSS on dorsal margin; merus with inner face having a semi-circle of setules (Fig. 6E); carpus with distoventral margin with two bipinnate setae; propodus with distoventral bipinnate seta; dactylus slightly shorter than unguis.

Pereopod-3 (Figs. 6F–6G). Similar to peropod-2 except: shorter; basis with one PSS on dorsal margin; merus shorter than carpus; dactylus slightly longer than unguis

Pereopod-4 (Figs. 6H–6K). Without coxa. Basis slightly wider than on pereopod 1–3, about five times as long as wide; ventroproximal margin setulose, with two PPS on mid-ventral margin. Ischium wider than long, with two bipinnate setae of unequal lengths on ventral margin. Merus shorter than carpus, about 1.9 times as long as wide, with two distoventral bipinnate setae. Carpus length subequal to propodus, about 2.5 times as long as wide; distoventral half margin setulose, with two mid-distal bipinnate setae; distodorsal margin with one sub-rectangular slightly bifid bipinnate seta (Fig. 6I); inner face with two mid-distally bipinnate setae (Fig. 6J). Propodus three times as long as wide; ventral margin with two rows of setules, distally with two bipinnate setae; mid-outer sub-distal and distal margin setose; dorsal margin with mid PSS, distally with spine-like apophysis and one bipinnate seta; mid-inner face sub-distal and distal margin setose (Fig. 6J). Dactylus together with unguis longer than propodus, dactylus length subequal to unguis, dactylus and unguis with two parallel rows of small setules (Fig. 6K).

Pereopod-5 (Figs. 7A–7B). Similar to peropod-4 except: slightly shorter; basis with three PSS on dorsal margin; inner face of carpus with one mid-distally bipinnate seta (Fig. 7B); dactylus shorter than unguis.

Pereopod-6 (Figs. 7C–7D). Similar to pereopod-5 except: slightly longer; basis with two PSS on dorsal margin; propodus with two bipinnate setae on distodorsal margin.

Pleopods. Absent.

Uropod (Figs. 2B–7E). Shorter than pleotelson (Fig. 2B). Basal article less than half length of endopod, about 1.3 times as long as wide, with two (one long and one short) distal simple setae on outer margin. Exopod vestigial, indicated by two simple setae. Endopod one-articled, about five times as long as wide, with four (two sub-distal and two distal) PSS, with two sub-distal and two distal simple setae of unequal lengths.

Male. Unknown.

Discussion

With the description of new Colombian species, seven of 18 species of Tanaella (Table 2) are known to be from the western Atlantic Ocean; among them, Tanaella ochracea from the western tip of Greenland, three (T. busteri, T. mclellandi, and T. prolixcauda) from Gulf of Mexico, T. kroyeri from off Brazil, T. unisetosa from the tip of Argentina, and T. quintanai sp. nov., which represents the first species of the genus described from the Caribbean (Fig. 10). During an earlier study by Morales-Núñez & Ardila (2018), it was first reported as Tanaella sp. in Caribbean waters, establishing the presence of the Family Tanaellidae in deep-waters off the Colombian Coast.

Sixteen out of eighteen of the described species of Tanaella have included at least a female, with only two species been described as males: T. busteri and T. prolixcauda. The new species from the Caribbean differs from T. busteri and T. prolixcauda by having (1) labium with apical lobe having a blunt seta (absent in busteri and prolixcauda) (Table 3), (2) cheliped with dactylus having a sub-proximal bipinnate seta on inner face (absent in busteri and prolixcauda) (Table 3), (3) pereopods 1–3 with basis having sub-dorsoproximal and sub-ventroproximal margins setulose (lacking setulose margins in busteri and prolixcauda) (Table 3), (4) pleotelson as long as pleonites 1–5 combined (shorter in busteri and prolixcauda) (Tables 1 and 3), and (5) uropod shorter than pleotelson (longer in busteri and prolixcauda) (Table 3).

Tanaella quintanai can be differentiated from T. ochracea and T. unisetos a by (1) cheliped with dactylus having a sub-proximal bipinnate seta on inner face (absent in ochracea and unisetosa) (Table 3), (2) pereopods 1–3 with basis having sub-dorsoproximal and sub-ventroproximal margins setulose (lacking setulose margins in ochracea and unisetosa) (Table 3), (3) pereopods 4–6 with basis having ventroproximal margin setulose (lacking setulose margin in ochracea and unisetosa) (Table 3), (4) pereopods 4–6 with unguis bearing two parallel rows of small setules (lacking parallel rows of small setules in ochracea and unisetosa), (5) pleotelson as long as pleonites 1–5 combined (shorter in ochracea and unisetosa) (Tables 1 and 3), and (6) uropod shorter than pleotelson (longer in ochracea and unisetosa).

Tanaella quintanai closely resembles T. kroyeri and T. mclellandi by having antennal article-3 with clear fusion line and uropod shorter than pleotelson (Table 3). Tanaella quintanai; however, can be distinguished from T. kroyeri and T. mclellandi by: (1) cheliped with dactylus having a sub-proximal bipinnate seta on inner face (absent in kroyeri and mclellandi) (Table 3), (2) pereopods 1–3 with basis having sub-dorsoproximal and sub-ventroproximal margins setulose (lacking setulose margins in kroyeri and mclellandi) (Table 3), (3) pereopods 4–6 with basis having ventroproximal margin setulose (lacking setulose margin in kroyeri and mclellandi) (Table 3), (4) pereopods 4–6 with unguis bearing two parallel rows of small setules (lacking parallel rows of small setules in kroyeri and mclellandi), and (5) pleotelson as long as pleonites 1–5 combined (shorter in kroyeri and mclellandi) (Tables 1 and 3).

Aside from the features indicated above, which were utilized to separate Tanaella quintanai from his congeners, Tanaella quintanai appears to be similar to T. unisetosa by having a maxilliped basis setose (Table 3), and also seems to be similar to T. forcifera by having the cheliped basis with sub-distal simple seta on dorsal margin (Table 3). Although it might be possible that these two characters have been overlooked and were not mentioned on the original descriptions and re-descriptions (Larsen & Heard, 2004) along the other members (i.e., 15 species) of the genus Tanaella. This indicates examination of addition type material or topotypic specimens of the other members of the genus needed to determine whether or not they exhibit these features.

Tanaella quintanai can be differentiated from the other species of Tanaella, as shown in the following identification key and Table 3.

Conclusions

This is the first tanaellid species described from Colombian waters and the only member of the genus Tanaella reported from the Caribbean; increasing the distribution range of the genus to the southern area of the Caribbean Sea (Fig. 10). Tanaella quintanai can be easily distinguished from all its congeners by having pereopods 4–6 with basis bearing ventroproximal margin setulose and pereopods 4–6 with unguis bearing two parallel rows of small setules. The lack of records for Tanaella in the coastal and deep waters of the Caribbean may be due to the lack of sampling in live-bottom habitats.

Supplemental Information