Pectenocaris evilsoni, Corgosinho & Rocha, 2024

Corgosinho, Paulo Henrique Costa & Rocha, Carlos Eduardo Falavigna Da, 2024, Pectenocaris gen. nov., a new Brazilian Parastenocaridinae Chappuis, 1940, and Afrocaris gen. nov., a West African Fontinalicaridinae Schminke, 2010 (Copepoda, Harpacticoida, Parastenocarididae), European Journal of Taxonomy 970, pp. 102-121 : 105-115

publication ID	https://doi.org/ 10.5852/ejt.2024.970.2751
publication LSID	lsid:zoobank.org:pub:6C0810FB-2F18-4BD8-91F3-F170C68E2410
DOI	https://doi.org/10.5281/zenodo.14278116
persistent identifier	https://treatment.plazi.org/id/030887F1-8836-FFF6-7E24-0A8F6CE4FB4C
treatment provided by	Plazi
scientific name	Pectenocaris evilsoni
status	gen. et sp. nov.

Treatment

Pectenocaris evilsoni gen. et sp. nov.

urn:lsid:zoobank.org:act:51332A89-B62B-4CF1-B9ED-A8A3C5173DAC

Figs 1–8 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig

Etymology

The specific epithet honors Mr Evilson Machado da Fonseca, owner of the area where the type locality of the species is located.

Type material

Holotype BRAZIL • ♂ (preserved in alcohol); State of Tocantins, Palmas, district of Taquaruçu de Cima, Taquaruçu Grande River , Tocantins River Basin ; 10°13′51″ S, 48°07′18″ W; 5 Aug. 2019; Carlos E.F. da Rocha leg.; saturated moss and among decaying leaves besides Evilson’s waterfall; MZUSP 45993 View Materials . GoogleMaps

Allotype BRAZIL • ♀ (preserved in alcohol); same data as for holotype; MZUSP 45994 View Materials . GoogleMaps

Paratypes BRAZIL • 46 ♂♂, 37 ♀♀ (preserved in alcohol); same data as for holotype; MZUSP 45995 View Materials GoogleMaps .

Other material examined

BRAZIL • 28 ♂♂, 29 ♀♀ (preserved in alcohol); State of Tocantins, Palmas, district of Taquaruçu de Cima, Taquaruçu Grande River , Tocantins River Basin ; 10°13′51″ S, 48°07′18″ W; 5 Aug. 2019; Carlos E.F. da Rocha leg.; saturated moss and decaying leaves besides Evilson’s waterfall GoogleMaps • 18 ♂♂, 8 ♀♀; same data as for preceding; 10°18′00″ S, 48°07′57″ W; saturate substrate composed of mud and decaying leaves in a ditch besides the track leading to Escorrega Macaco waterfall GoogleMaps .

Description

Male Body length, measured from tip of rostrum to posterior margin of caudal rami, 330–347 µm in 10 specimens measured (average 337 µm). Cephalothorax ( Figs 1A View Fig , 2A View Fig , 8A View Fig ) with large dorsal integumental window on posterior half. Genital somite and three subsequent urosomites each with transverse, narrow integumental window on anterior dorsal surface. Integumental pores and sensilla arrangement as shown in Figs 1A View Fig , 2A View Fig , 8A View Fig . Structure of all sensilla shown in Fig. 7F View Fig . Ventral surface of prosome among swimming legs smooth. Third urosomal somite ( Figs 5G View Fig , 7A, 7C View Fig ) with ventral flap distally, marking vestigial P6. Spermatophore ( Figs 1A View Fig , 2A View Fig ) Spermatophore ovoid, visible within body occupying pediger 5 and genital somite. Telson ( Figs 1A View Fig , 2A, 2B View Fig , 8A View Fig ) 1.2 × as long as wide and twice the length of preceding somite; a dorsally produced backwards into pseudoperculum. Anal area with rows of setules ( Fig. 7E View Fig ). Fu ( Figs 2B View Fig , 8A View Fig ) twice as long as broad, setae I to III the shortest, grouped and sub-terminally inserted. SETA IV. Dorso-laterally placed, shorter than Fu, and sparsely uniserrate in distal half; seta V robust and sparsely setulose, 6 × length of caudal ramus; seta VI 1–1.2 × length of caudal ramus, and with row of setules at base ventrally; seta VII almost as long as seta VI, implanted dorsally near inner margin of ramus, slightly below the insertion level of setae I–III (i.e., at about 0.6 length of ramus).

A1. Haplocer of 8 segments and armed as shown in Fig. 3A View Fig . Ae on segment 5 wider and longer than that on last segment. Armature formula 0, 6, 4, 2, 5+1+ae, 2+foliaceous spine,1+ foliaceous spine, 7+ acrothek (2+ae).

A2 ( Fig. 3B View Fig ). Consisting of unarmed short coxa, basis with two transversal spinule groups, and onesegmented enp bearing 7 elements (two inner unipinnate spines, two distal inner spines also unipinnate, two distal geniculate setae, and one distal and outer unipinnate spines), and hyaline serrulate frill near apex on posterior surface (indicated by an arrow). Exopod reduced to knob with pinnate apical seta.

LABRUM AND LABIUM. As in Fig. 3G. View Fig

MD ( Fig. 3C, C View Fig *). With coxa expanded into gnathobase with teeth. Palp uniramus, cylindrical, with two apical setae of same length implanted at base of sharp protrusion.

MX 1 ( Fig. 3D View Fig ). Comprised of praecoxal arthrite with spinule on inner surface, six robust, apically curved and unipinnate apical setaeand tubular seta on outer margin. Coxal endite bearing seta ending in pointed projection. Basis and enp merged together. Basal endite with three setae, two of them ending in pointed projection. Enp represented by seta implanted on tubercule. Exopod absent. All setae transformed in hollowed tube.

MX 2 ( Fig. 3E View Fig ). Allobasis with two endites; proximal endite with one seta; distal endite bearing three setae, the longest one comb-shaped, the remaining two os same lenght; proximal endopodal segment drawn out into denticulate claw; distal endopodal segment represented by two setae of subequal lengtht. Endites setae, and 2 nd enp setae transformed in hollowed tubes. Claw of the proximal endopodal segment with subdistal pore.

MXP ( Fig. 3F View Fig ). Prehensile. Terminal segment with spinulose seta on tip.

P 1 ( Fig. 4A View Fig ), 2, 4. Biramous, with three-segmented exp. P1 ( Fig. 4A View Fig ) biramous. Coxa with two rows of spinules on anterior surface. Basis bearing gland pore and three rows of strong spinules on anterior surface. Exp three-segmented, with outer spine on proximal segment; second segment without spine but row of spinules at outer corner; and terminal segment with two spines and two geniculate setae apically. Enp 2-segmented; enp-1 slightly longer than exp-1 and 2 combined, with transversal row of four spinules internally, at approximate ⅔ of enp length, and two groups (one proximal and one distal) of transversal spinules along outer margin; enp-2 with serrate outer spine and geniculate inner seta apically.

P2 ( Fig. 4B View Fig ). Coxa with two rows of spinules on anterior surface. Basis bearing row of spinules near the insertion of enp and exp, outer row of spinules, and outer pore. Exp with hyaline frills at inner corners of proximal and apical segments. Proximal segment with spine on distal outer corner and rows of spinules on outer margin and at outer corner. Median segment with apical spinules. Terminal segment armed with three elements: one short and unipinnate outer spine, one unipinnate outer distal seta shorter that bipinnate inner distal seta. Enp cylindrical, almost half length of exp-1, armed with seta implanted subterminally and directed towards middle line of body; apex blunt, bearing group of spinules.

P3 ( Figs 4C View Fig , 6B View Fig ). Consisting of coxa, basis and unisegmented exp (exp-1 and 2 fused); enp absent. Coxa with two spinules on outer margin. Basis bearing long outer seta, transversal row of long spinules near outer distal corner, curved row of spinules on anterior surface, and short row of spinules on posterior surface. Exp long and narrow, with basal protuberance and two rows of outer spinules along posterior surface. Terminal apophysis sigmoidal, elongated, slightly bent inwards; thumb digitiform, tapering towards tip, straight, reaching past end of apophysis ( Fig. 6B View Fig ).

P 4 ( Figs 4D View Fig , 6C–D View Fig ). Coxa with row of spinules on anterior and posterior surfaces. Basis with outer seta, outer pore, and row of spinules between seta and exp. Exp three-segmented. Exp-1with spine at outer corner and three transversal rows of spinules; inner border with row of long, strong spinules, each one slightly curved backwards; all spinules equal in length, except for distal four spinules shorter than others and implanted on triangular expansion of exp-1. Exp-2 with row of spinules along last third of inner border, continuing on distal margin on anterior and lateral surfaces. Exp-3 with one outer unipinnate spine, ⅔ the length of bipinnate inner distal seta, inner fringed hyaline frill at inner corner and row of spinules on outer corner. Enp reduced to filiform segment; row of curved and flattened robust spinules, with blunt tip implanted in front of it on anterior surface of basis.

P5 ( Figs 4E View Fig , 7A, C View Fig ). Not fused to intercoxal sclerite, represented by subtriangular plate extending into wide triangular medial process with pointed tip, and bearing four setaere; outermost basipodal seta about 1.6 × as long as plate, and outer pore.

P6 ( Fig. 7A, C View Fig ). Vestigial, appearing as unarmed and unornamented fused plate.

Female

Body length, excluding caudal setae, varying from 365 to 390 µm in 7 specimens measured (average 384 µm). Integumental sensilla and pores distributed as shown in Fig. 1B View Fig . Cephalothorax with large dorsal integumental window on posterior half ( Figs 1B View Fig , 8B View Fig ). Genital double somite and two subsequent urosomites each with transverse narrow integumental window on anterior dorsal surface ( Fig. 1B View Fig ). Ventral surface of prosome smooth. Genital field rectangular, much broader than high with cuticular thickenings along transversal slit representing vestigial P6 forming design as shown in Fig. 7B, D View Fig . Anal somite and Fu as in male. None of females found carried egg sacs.

A1 ( Fig. 5A View Fig ) of 7 segments armed with 0, 4, 3, 2+ae, 1, 1, 7+ acrothek (2+ae). Ae on segments 4 longer than on segment 7.

A2 and mouthparts as in male.

P1, P2 ( Fig. 5B View Fig ) and P5 ( Fig. 5E View Fig ) as in male.

P3 ( Fig. 5 C View Fig ) two-segmented exp. Enp protruded into blunt concave projection to accommodate spinule implanted at medium length.

P4 ( Fig. 5D View Fig ) coxa with curved row of short spinules. Basis with row of spinules on anterior surface, between insertion of outer seta and exp. Exp three-segmented; exp-1 with distal outer spine and three rows of spinules on the outer margin, and one inner distal row of spinules; exp-2 with distal row of spinules; exp-3 bearing one unipennate outer spine, distal inner bipinnate seta almost twice as long as outer spine, an inner distal hyaline frill, and two rows of spinules on apex. P4 basis with spinular row around enp insertion, with outer row of spinules, outer seta and outer pore; enp is short uni-segmented (¾ length of corresponding exp-1), and cylindrical with blunt tip, with two subapical, longitudinal spinules of same length.

Acompanying fauna

Copepoda Cyclopidae ( Paracyclops sp. , Ectocyclops sp. and Metacyclops sp. ); Copepoda Canthocamptidae ; Ostracoda ( Darwinulidae and others); Acari (Hydrachnida and others); Mollusca (Gastropoda and Bivalvia); Tardigrada; Oligochaeta; and insect larvae.