Psammonitocrella kumeyaayi, Corgosinho & Kihara & Arbizu, 2020

Corgosinho, Paulo Henrique Costa, Kihara, Terue Cristina & Arbizu, Pedro Martinez, 2020, A new species of Psammonitocrella Huys, 2009 (Copepoda, Harpacticoida, Ameiridae) from California (USA), with a discussion of the relationship between Psammonitocrella and Parastenocarididae, ZooKeys 996, pp. 19-35 : 19

Psammonitocrella kumeyaayi sp. nov. Figs 1 , 2 , 3 , 4

Material examined.

Holotype: One male dissected and mounted onto 7 slides (reg. no. SMF 37256/1-7; 1-7 refers to the number of slides).

Type locality: San Clemente Canyon, San Diego, California, USA (32.8446°N, 117.1949°W).

Description of male.

Total length 302 µm, measured from rostrum to end of furca. Rostrum not fused to cph, with two sensilla on tip (Fig. 1A ). First and second free prosomal segments with large oval window on each side of the body (Fig. 1A ). Ur4 and 5 weakly ornamented with small spinules. Pattern of sensilla and pores as depicted (Fig. 1A ). Telson weakly ornamented with small spinules on anal operculum; laterally with few spinules and three long tube pores (Fig. 1A ; tube pores marked with arrowheads). Fu (Fig. 1A, E ) cylindrical, tapering distally, approximately 2.5 times longer than wide, 1.4 times longer than telson, with dorsal pore subdistally and three long tube pores -two on outer margin, one on inner margin (marked with asterisk on Fig. 1E ) armed with seven setae; setae I and II inserted dorsally on proximal half, seta I shorter; seta III (Fig. 1A , broken in Fig. 1E ) on distal third, longer than seta I, shorter than seta II; seta IV inserted distally on outer margin, longer than seta II; seta V longest (broken in Fig. 1A and E ); seta VI inserted distally on inner margin, almost as long as seta I; seta VII broken (Fig. 1A and E ), tetra-articulated at basis, inserted dorsally at the same level as seta III. Spermatophore (Fig. 1A, B ) occupying almost the whole length of Ur4 and 5 combined.

A1 haplocer (Fig. 2A-C ), 10-segmented; armature and ornamentation as follows: 1(1)/2(7)/3(5)/4(2)/5(1ms+4+(1+ae))/6(1ms)/7(3+ms)/8(4ms +1)/9(4)/10(4+acrothek). Acrothek consisting of two setae fused to aesthetasc.

A2 (Fig. 2D, E ) basis without abexopodal armature; one-segmented exp with long unipinate seta and two spines with comb tip; enp1 rectangular and smooth; enp2 with two inner marginal spines, four apical geniculated setae, and one geniculate outer seta fused basally to small seta.

Md (Fig. 2 F, G ) with oral bulge (marked with asterisk), opposite to md palp. Gnathobase smooth, elongate (Fig. 2F ; depicted as shorter in 2G due to a different viewing angle) with weakly developed cutting edge; oral margin without distal seta. Palp uniramous, comprising smooth basis and one-segmented enp with five distal setae.

Mx1 (Fig. 2H ). Praecoxa, coxa and basis fused. Praecoxal arthrite rectangular; with row of proximal spinules close to the insertion site of the coxal and basal endites; with three distal spines, a minute oral seta and two surface aboral setae. Coxal endite with three long apical setae. Basis approximately of the same length of coxal endite, with four long apical setae. Enp and exp absent.

Mx2 (Fig. 2I ). Syncoxal endite with modified finely bipinnate spine with rounded tip. Basal endite with spine with comb-like tip and fused to endite, and two setae. Enp1 drawn into claw, proximally with accessory spine with comb-like tip; enp2 represented by two setae.

Mxp (Fig. 2J ) prehensile, with smooth syncoxa and basis, the former slightly shorter than the latter. Enp represented by long and slightly curved claw, ornamented with medial-distal row of spinules along concave side.

P1 (Fig. 3A ). Intercoxal sclerite smooth, sub-rectangular, wider than long. Coxa with anterior rows of medial, medial-distal, and inner small spinules. Basis with rows of spinules close to insertion site of exp and enp, and at base of outer element; with inner spine and outer seta, the former not sexually dimorphic. Exp three-segmented; exp1 with outer row of spinules and outer unipinnate spine; exp2 without outer spine, with outer row of spinules and with short unipinnate inner seta; exp3 with outer row of spinules, two unipinnate outer spines and two unipinnate and geniculate distal setae. Enp three-segmented; enp1 unarmed, slightly longer than exp1, reaching middle of exp2, with inner, distal and outer rows of spinules; enp2 unarmed, shorter than enp1, with inner, distal, outer and posterior rows of spinules; enp3 shortest, with inner row of spinules, one distal inner and one geniculate distal outer seta, the latter unipinnate distally.

P2 (Fig. 3B ). Intercoxal sclerite almost as wide as long, with proximal hump, outer distal extensions rounded, medial-distal part concave. Coxa unornamented. Basis with medial row of spinules, with transverse spinular row close to insertion of exp and at base of outer short seta; with medial pore. Exopodal segments subequal in size; exp1 with outer and distal rows of spinules, with inner distal hyaline frill and unipinnate outer spine; exp2 ornamented as in exp1, with unipinnate outer spine and unipinnate inner spiniform seta; exp3 with outer and distal rows of spinules, with outer unipinnate spine and inner spiniform seta, the latter with pinnate outer margin and with two inner setules. Enp two-segmented, slightly longer than exp1; enp1 unornamented, unarmed; enp2 with small spinule and spiniform distal seta.

P3 (Fig. 4A ) with intercoxal sclerite as in P2. Triangular praecoxa and square coxa unornamented. Basis with row of spinules near insertion of enp, with row of spinules between exp and outer long seta, with proximal outer pore. Exp three-segmented, exp1-3 subequal in size; exp1 with outer and distal rows of spinules, with inner hyaline frill, and outer unipinnate spine; exp2 ornamented as in exp1, with unipinnate outer spine and unipinnate inner spiniform seta; exp3 with outer row of spinules, outer unipinnate spine and inner unipinate seta. Enp two-segmented, almost as long as exp1; enp1 unornamented, unarmed; enp2 with small spinule and spiniform seta distally.

P4 (Fig. 4B ). Intercoxal sclerite wider than long, outer distal extensions short, with proximal and distal-medial parts concave. Coxa unornamented. Basis without ornamentation, with proximal outer pore, and outer long seta. Exp three-segmented; exp1-3 subequal in size; exp1 with outer and distal spinules, with inner hyaline frill, and outer unipinnate spine; exp2 ornamented as in exp1, without outer spine, with unipinnate inner spiniform seta; exp3 with outer row of spinules, with outer bipinnate spine, distal long unipinnate seta, and inner bipinnate spine. Enp absent.

P5 (Fig. 1C, D ). Rectangular benps united by small intercoxal sclerite, with long outer basal seta, and two small bipinnate spines on endopodal lobe. Exp one-segmented, square, with four elements (setae and spines) of variable shape, size and ornamentation in left (Fig. 1C ) and right limbs (Fig. 1D ); right exp (Fig. 1C ) with long and smooth outer seta, short bipinnate distal spine, and comparatively longer bipinnate distal spine, and inner seta, the latter with tuft of setules distally on both sides; left exp (Fig. 1D ) with long and smooth outer seta (shorter than in the right limb), distal seta smooth, a distal tiny element probably representing a reduced spine, and an inner bipinnate seta.

P6 (not shown) represented by unarmed cuticular flap.

Etymology.

The specific epithet " kumeyaayi " refers to the Kumeyaay native American people, who inhabited the area of San Diego County for 10,000 years. Evidence of their presence still remains in San Clemente Canyon.

Remarks.

Female unknown. The presence of integumental windows on the third and fourth pedigerous somites was reported by Karanovic and Hancock (2009: 11, table 2; character 2) for most species analyzed by them, including Eduardonitocrella mexicana , S. orghidani , and their closely related species Psammonitocrella boultoni and P. longifurcata . This character was, however, never mentioned by Rouch (1992) or illustrated in the original description, and Karanovic and Hancock (2009) did not mention whether they inspected the type material of Psammonitocrella . However, it is possible that integumental windows are present on some pedigerous somites within the genus Psammonitocrella , as indicated by the presence of lateral integumental windows on the second and third pedigerous somites of Psammonitocrella kumeyaayi sp. nov. The probable loss of lateral integumental windows in Psammonitocrella boultoni and P. longifurcata should be considered as derived. The presence of lateral integumental windows is a potential synapomorphy for a larger group of groundwater ameirids as proposed by Karanovic and Hancock (2009). The absence of the outer spine of the P4exp2 is an autapomorphy for the new species.

Figures

Figure 1. Psammonitocrella kumeyaayi sp. nov., male. A Lateral habitus of male B spermatophore C right P 5 D left P 5 E furca. Arrowheads on (A) and asterisks on (E) mark tube pores. Roman numerals indicate each seta on (E).

Figure 2. Psammonitocrella kumeyaayi sp. nov., male. A 6 th to 10 thA 1 segments B 5 thA 1 segment C 1 st to 5 thA 1 segments D enp 2 of A 2 E A 2 with unarmed enp 2 F md G md with unarmed palp H mx 1 I mx 2 J mxp. Asterisk mark the setae of the 4 thA 1 segment, and the md oral bulge.

Figure 3. Psammonitocrella kumeyaayi sp. nov., male. A P 1 B P 2. Asterisks mark the position of apomorphies represented by the loss of spines or setae. DAS = Distal apical seta; DOS = distal outer seta.

Figure 4. Psammonitocrella kumeyaayi sp. nov., male. A P 3 with detached exp 2 and exp 3 B P 4. Asterisks mark the position of apomorphies represented by the loss of spines or setae. Arrow indicates the absence of the enp. DAS = Distal apical seta; DOS = distal outer seta; IAS = inner apical seta.