Maraenobiotus wellsi, Gaviria & Defaye, 2021

Gaviria, Santiago & Defaye, Danielle, 2021, A new species of Maraenobiotus Mrázek, 1893 (Copepoda: Harpacticoida Canthocamptidae) from Colombian Andean mosses, with an identification key for the American species, Zootaxa 5051 (1), pp. 101-116 : 104-110

publication ID	https://doi.org/ 10.11646/zootaxa.5051.1.9
publication LSID	lsid:zoobank.org:pub:FC1E4C59-C9A9-48F3-8C4A-662FA13A25A7
DOI	https://doi.org/10.5281/zenodo.5576222
persistent identifier	https://treatment.plazi.org/id/03B5010B-9608-FFA4-B980-CCD9FD3BE882
treatment provided by	Plazi
scientific name	Maraenobiotus wellsi
status	sp. nov.

Treatment

Maraenobiotus wellsi sp. nov.

( Figs. 2–5 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Type locality. Wet mosses of the genus Sphagnum growing on stones in the Páramo de Cómbita (the humid region of the Andean Cordillera above the Andean forest), Boyacá, Colombia (5°45‘00‘‘N, 73°20‘29‘‘W) at 3,039 m.a.s.l. ( Fig. 1 View FIGURE 1 ) GoogleMaps .

Material examined. Holotype female, dissected and mounted on one slide in lactophenol, registered as UPTC- L 0001. Paratype copepodid UPTC-L 0002 . Both specimens from the type locality .

Etymology. The new species is named after the late Professor John B. J. Wells, School of Biological Sciences, Victoria University of Wellington, New Zealand, for his valuable contribution to the systematics of harpacticoid copepods.

Differential diagnosis. Female. Maraenobiotus of small size, with urosomites 2–5 with rows of spinules ventrally and laterally near the posterior margin, dorsal row of spines located only near free lateral margin. Urosomites 2 (genital-double somite) and 3 with a ventral row of spinules showing a gap in the middle of the row. Anal operculum with nine spinules, reaching beyond the posteriormost margin of the anal somite. Caudal rami conical, longer than wide, caudal setae IV and V not inflated at their base proximal to breaking point. Seta IV slightly inflated distal of breaking point. Antennary exopod one-segmented with four setae. Mandibular palp one-segmented with four setae. Maxilliped comprising syncoxa, basis and 1-segmented endopod bearing one seta and one claw. Leg 1 with 2-segmented exopod and endopod. Legs 2–4 with 3-segmented exopod and 2-segmented endopod. Last segment of exopod of legs l–4 with five major elements, last segment of endopod of legs 1–4 with three, four, five and five major elements, respectively. Leg 5 exopodal lobe longer than baseoendopod, exopod with three elements, baseoendopod distal lobe with five elements.

Description of holotype (female). Habitus ( Fig. 2A–B View FIGURE 2 ) cylindrical, nauplius eye colourless. Body length 575 µm, measured from tip of rostrum to posterior margin of caudal rami (without caudal setae). Cephalosome constituting 24% of body length. Body comprising prosome (consisting of cephalosome and three free pedigerous somites, first pedigerous somite fused to cephalosome) and urosome (consisting of fifth pedigerous somite, genital doublesomite, three abdominal somites and caudal rami). Prosome and urosome with sensillae distributed dorsally and laterally as shown in Fig. 2A–B View FIGURE 2 . Cephalosome with median small oval integumentary window located dorsally. Body somites with smooth posterior margin. Genital double-somite completely fused. Median copulatory pore located at about halfway the length of genital double-somite. Urosomites 2–5 with row of spinules inserted near posterior margin of somite, dorsally only near lateral margin. Urosomites 2 and 3 bearing ventral row of spinules showing gap in the middle.

Anal somite ( Fig. 4A View FIGURE 4 ) with lateroventral spinules near posterior margin, extending beyond posterior margin of somite. Anal operculum ( Fig. 4A View FIGURE 4 ) large, trapezoidal, free margin with nine spinules, extending beyond posteriormost margin of anal somite.

Caudal rami conical, about 1.3 times as long as wide ( Fig. 4A View FIGURE 4 ). Numbering system for setation elements, see Fig. 4A View FIGURE 4 . Rami with two lateral setae ( II and III, seta I absent), seta II inserted approximately in middle of ramus, seta III inserted beyond middle of ramus (seta II inserted anteriorly to dorsal seta VII, seta III inserted approximately at same level as seta VII), three terminal setae ( IV – VI) and one dorsal seta ( VII). Setae IV, V and VII with breaking plane. Setae IV and V not inflated proximal to breaking plane. Seta IV slightly inflated at its base, distal to breaking plane, spinulose, 1.7 times longer than caudal ramus. Seta V long and spinulose (observed in paratype copepodid, Fig. 2C View FIGURE 2 ), distal part of seta V of holotype lost during dissection. Seta V partially inserted ventral to seta IV. Seta VI thin and naked, shorter than caudal ramus. Dorsal seta (seta VII) inserted at posterior third of ramus. Row of eight spinules inserted ventrally near posterior margin of ramus ( Fig. 3A View FIGURE 3 ), row of four spinules inserted distally near inner margin of ramus ( Figs. 3A View FIGURE 3 , 4A View FIGURE 4 ), two small spinules on dorsal surface near base of dorsal margin and one spinule on lateral surface inserted near each base of setae II and III ( Fig. 4A–B View FIGURE 4 ) .

Antennule 8-segmented ( Fig. 3B View FIGURE 3 ), with armature formula from distal to apical segment: 0, 4, 3, 1 + aesthetasc (seta and aesthetasc with conjointed bases), 2, 0, 1, 4 + 2 and aesthetasc (2 setae and aesthetasc with conjointed bases). Aesthetasc of segment 4 reaching middle of segment 8, slightly longer than the three distal segments combined. Aesthetasc on segment 8 almost as long as the three distal segments combined.

Antenna ( Fig. 3C View FIGURE 3 ), with praecoxa and allobasis lacking ornamentation. Endopod one-segmented, inner margin with four spinules followed by two naked spines from proximal to distal, apical margin with one naked spine, two naked setae and three geniculate setae, most outer geniculate seta shorter than the other two. Exopod one-segmented, inner margin with one bipinnate seta, distal margin with two naked setae and one outer bipinnate seta.

Mandible ( Fig. 4C View FIGURE 4 ), palp one-segmented with four distal setae. Coxa with outer lobe, gnathobase with five teeth and one lateral seta.

Maxillule ( Fig. 4D View FIGURE 4 ) 3-segmented, praecoxal arthrite with five apical spines (three robust, one bifid, one thin). Coxa with one strong spine and one long seta. Basis with distal spine and three accessory lateral setae.

Maxilla ( Fig. 4E View FIGURE 4 ), syncoxa with two endites, outer endite inflated at its basis, with two lateral accessory setae, inner endite with one naked seta. Basis with claw accompanied at base by two accessory lateral setae. Endopod absent.

Maxilliped ( Fig. 4F View FIGURE 4 ), syncoxa short, ornamented with one bipinnate seta on distal inner corner and a row of minute spinules on outer margin. Basis with a row of spinules near inner margin. Endopod one-segmented, bearing one claw and one seta on distal margin.

Legs 1–4: for major armature, see Table 1 View TABLE 1 , intercoxal sclerite with concave distal margin and naked surface. Distribution of spinules on segments of leg rami (exopod and endopod) as shown in Fig. 5A–D View FIGURE 5 .

Leg 1 ( Fig. 5A View FIGURE 5 ): coxa with one outer short spinule and two smaller spinules inserted on distal corner; basis with one spine on outer margin, a row of spinules on anterior surface near base of endopod and one strong spine on inner margin, inserted on distal corner near base of endopod. Exopod and endopod 2-segmented. Exopod shorter than endopod; first segment with one unipinnate spine on outer margin; second segment longer than first with five major elements: two unipinnate spines on outer margin, one unipinnate spine and one geniculate seta on apical margin, and one geniculate seta on inner margin. Geniculate setae longest. Endopod with first segment as long as exopod, 2.5 times longer than wide, inner margin with one naked spine inserted subapically; second segment, apical margin with two naked setae, inner seta 2.7 times longer than outer seta and 1.2 times longer than endopod, inner margin with one naked spine inserted subapically.

Leg 2 ( Fig. 5B View FIGURE 5 ): coxa with one very large spinule on distal outer corner; basis with one unipinnate spine on distal outer margin. Exopod 3-segmented; first and second segments with one robust spine on outer margin subapically; third segment with one unipinnate robust spine inserted subapically, apical margin with one outer unipinnate spine and one inner bipinnate seta, spine shorter than seta, inner margin with two naked slender spines. Endopod 2- segmented, as long as the two first exopodal segments combined; first segment, inner margin with one naked spine inserted subapically; second segment, distal margin with one bipinnate seta and one unipinnate seta, inner margin with two naked setae.

Leg 3 ( Fig. 5C View FIGURE 5 ): coxa, without armature on outer margin, anterior surface with row of small spinules near distal inner corner; basis with long naked seta on outer margin. Exopod 3-segmented; first and second segments as in leg 2; third segment with one unipinnate robust spine on outer margin, apical margin with one outer unipinnate spine and one bipinnate seta, inner margin with two unipinnate slender spines inserted at 1/2 and 2/3 of segment. Endopod 2-segmented; first segment with one naked slender spine on inner margin; second segment with one bipinnate seta on outer margin, apical margin with two bipinnate setae, outer seta 2.5 times longer than inner seta, inner margin with two naked slender spines.

Leg 4 ( Fig. 5D View FIGURE 5 ): smaller than leg 3, coxa without armature and ornamentation. Basis with naked seta on outer margin. Exopod 3-segmented; first segment with unipinnate robust spine on outer margin; second segment with unipinnate robust spine on outer margin and naked slender spine on inner margin; third segment, outer margin with two bipinnate robust spines inserted distally, apical margin with two bipinnate, almost identical, setae, inner margin with one long bipinnate seta. Endopod 2-segmented; first segment as in leg 3; second segment with five bipinnate setae: outer margin with one seta inserted subapically, apical margin with two setae, inner seta 1.5 times longer than outer seta, inner margin with two setae inserted at 1/2 and 3/4 of segment.

Leg 5 ( Fig. 4G View FIGURE 4 ): intercoxal sclerite fused to baseoendopods. Baseoendopods separated at base, lateral margin with one long naked seta; endopodal lobe short, not reaching beyond 1/3 of length of exopod, bearing five bipinnate spines with following length ratios: 1.25 (outermost):1.5:1.0:1:0:1.0 (innermost). Exopod oval, 1.7 times longer than wide, with three elements: outer margin with one naked seta inserted subapically, apical margin with one naked outer seta and one bipinnate inner spine, seta 2.9 times longer than spine.

Leg 6: not observed.

Remark. The sample also contained one copepodid specimen (length 388 µm) (UPTC–L 0002) (antennule 7- segmented, anal somite longer than preceding somite), with caudal rami bearing all 6 caudal setae). As the holotype was missing the distal portion of seta V (beyond the breaking plane, possibly broken during sorting), its existence could be confirmed by its presence in the copepodid.