Helmutkunzia xiamenensis, Mu & Huys, 2021

Mu, Fanghong & Huys, Rony, 2021, A new species of Helmutkunzia Wells & Rao, 1976 from an intertidal sandy beach in Xiamen, China and proposal of Pseudobalucopsylla gen. nov. (Copepoda Harpacticoida, Miraciidae), Zootaxa 5051 (1), pp. 487-505 : 489-495

publication ID	https://doi.org/ 10.11646/zootaxa.5051.1.19
publication LSID	lsid:zoobank.org:pub:A607CB5B-51E7-45FD-9104-980175BBB163
DOI	https://doi.org/10.5281/zenodo.5563799
persistent identifier	https://treatment.plazi.org/id/D0D51818-C47D-462A-8AE1-ADB211093342
taxon LSID	lsid:zoobank.org:act:D0D51818-C47D-462A-8AE1-ADB211093342
treatment provided by	Plazi
scientific name	Helmutkunzia xiamenensis
status	sp. nov.

Treatment

Helmutkunzia xiamenensis sp. nov.

urn:lsid:zoobank.org:act:D0D51818-C47D-462A-8AE1-ADB211093342

( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Type locality. Dadeji Beach , Xiamen, China (24°26’30” N, 118°4’12” E) GoogleMaps .

Material examined. Holotype: adult ♀ dissected on ten slides ( OUCBL reg. no. 2019.025) . Paratypes: adult ♂ dissected on eleven slides ( OUCBL reg. no. 2019.026), four ♀♀ and ten ♂♂ preserved in 4% formalin ( OUCBL reg. nos 2019.027–040). All paratypes were collected from the type locality by Dr Er Hua on 24 July 2010 .

Description of female. Total body length 400–440 µm (mean = 413 µm, n = 5) (excluding caudal rami).

Body linear, cylindrical, widest at posterior margin of cephalothorax, slightly tapering posteriorly, without clear distinction between prosome and urosome ( Fig. 1A–B View FIGURE 1 ). All somites except for penultimate one furnished with sensillae as figured. All somites with distinct integumental pores. All somites except anal one with well developed hyaline frills; those of cephalothorax and pedigerous somites plain, those of genital double-somite and abdominal somites finely incised ( Fig. 1A–C View FIGURE 1 ). Spinular ornamentation lacking on all somites except for anal somite bearing coarse spinules laterally and ventrally around posterior margin ( Fig. 1B–D View FIGURE 1 ). Genital double-somite ( Fig. 1A–B View FIGURE 1 ) completely fused; original segmentation marked laterally by transverse sub-cuticular ribs. Genital field ( Fig. 1E View FIGURE 1 ) with moderately sized midventral copulatory pore and paired gonopores, each covered by vestigial P6 bearing three elements, innermost one longest and smooth, middle one shortest and smooth, outermost minutely bipinnate and slightly longer than middle one. Seminal receptacles paired. Anal somite with unornamented anal operculum concealed under incised hyaline frill of penultimate somite ( Fig. 1C View FIGURE 1 ).

Caudal rami ( Fig. 1C–D View FIGURE 1 ) slightly longer than broad, length/width ratio about 1.1; dorsal surface with transverse oblique row of spinules in proximal half; seta I (anterolateral accessory seta) minute and naked, located ventral to seta II; seta II (anterolateral seta) long, proximal half inflated; seta III (posteroventral seta) located near outer distal corner, long, slender and smooth; seta IV (outer terminal seta) and seta V (inner terminal seta) well developed, with weakly developed fracture planes; seta IV pinnate, seta V smooth; seta VI (terminal accessory seta) arising from inner distal corner, long and smooth; seta VII (dorsal seta) tri-articulated at base, smooth. Integumental pores present dorsally (two) and ventrally (one).

Rostrum ( Fig. 1A View FIGURE 1 ) defined at base, elongate, triangular, reaching to about middle of second antennulary segment, with one pair of subapical sensilla.

Antennule ( Fig. 2A–B View FIGURE 2 ) 8-segmented; all segments without ornamentation; segment 2 largest, segments 5–7 small; segment 4 with long aesthetasc (75 μm). Acrothek consisting of short aesthetasc and two basally fused setae. Setal formula as follows: 1-[1 pinnate], 2-[8 + 2 pinnate], 3-[8], 4–[3 + (1 + ae)], 5–[2], 6-[3 + 1 pinnate], 7-[4], 8-[5 + acrothek].

Antenna ( Fig. 2C View FIGURE 2 ). Coxa well developed, with row of setules. Basis clearly defined from proximal endopodal segment, with few setules near distal corner. Exopod 3-segmented; proximal segment elongate, with seta at outer distal corner; middle segment short, unarmed; distal segment with one lateral and two terminal setae, one of which stronger than the other. Endopod 2-segmented, proximal segment with pinnate seta and row of strong spinules along abexopodal margin; distal segment with two rows of strong spinules on outer margin, row of smaller spinules on inner margin and on ventral surface; lateral armature consisting of two spines; apical armature consisting of one pinnate spine and four geniculate setae, outermost of which pinnate around geniculation and fused basally to slender naked seta.

Labrum ( Fig. 2D View FIGURE 2 ). Free margin with two lateral rows of small teeth and one median row of spinules.

Mandible ( Fig. 2E View FIGURE 2 ). Gnathobase with series of unicuspidate or multicuspidate teeth, with one pinnate seta at dorsal corner. Basis elongate, with one smooth and two plumose setae on inner distal margin; ornamentation along inner margin consisting of short spinules medially and long spinules distally. Exopod 2-segmented; exp-1 wider than exp-2, inner margin with pinnate proximal seta and smooth distal one; exp-2 with three setae, longest two fused at base. Endopod 1-segmented; inner margin with two proximal and three subdistal setae; apex with three apical setae sharing a common base.

Maxillule ( Fig. 2F View FIGURE 2 ). Praecoxal arthrite with eight spines around distal margin and two setae on anterior surface; inner margin with one pinnate and one smooth seta and few spinules. Coxal endite short; with two smooth setae apically. Basis elongate; endites not discrete; with four smooth setae along outer margin and three elements apically (one pinnate seta, one smooth seta and one curved, unipinnate spine); with few spinules near distal inner corner. Rami not defined at base. Exopod with two confluent smooth setae apically and with setules along inner margin. Endopod with row of setules along outer margin and four setae apically (one pinnate, three smooth).

Maxilla ( Fig. 2G View FIGURE 2 ). Syncoxa with spinules along inner and outer margins; with three endites; proximal endite with two short, smooth setae; middle and distal endites each with one basally fused and one articulating spine, all elements unipinnate. Allobasis produced into slightly curved unipinnate claw; with one pinnate and two smooth accessory setae. Endopod discrete, 1-segmented, with seven setae.

Maxilliped ( Fig. 2H View FIGURE 2 ). Syncoxa with one smooth and three pinnate setae; with few spinules near proximal inner corner. Basis with one row of long spinules and two naked setae on palmar margin. Endopod an elongate segment bearing a terminal, unipinnate claw and three smooth accessory setae.

P1 ( Fig. 2I View FIGURE 2 ). Intercoxal sclerite small, without ornamentation. Praecoxa triangular.Anterior surface of coxa with three rows of long spinules and one row of small spinules. Basis with rows of spinules along inner and distal margins and near bases of inner and outer pinnate spines. Exopod 3-segmented; each segment with a row of strong spinules along outer margin; exp-2 with a row of setules along inner margin; exp-3 with a row of setules along inner margin, and with two geniculate, pinnate, distal setae and two pinnate outer spines. Endopod 3-segmented; enp-1 about 1.3 times longer than enp-2 and enp-3 combined, almost reaching to distal margin of exp-3, with row of spinules along outer margin, row of setules along inner margin and plumose inner seta in distal quarter; enp-2 short, with plumose inner seta and several spinules along outer margin; enp-3 about twice as long as enp-2, with row of spinules along outer margin and one plumose seta, one geniculate pinnate seta and one pinnate spine apically.

P2–P4 ( Fig. 3A–C View FIGURE 3 ). Intercoxal sclerites well developed, deeply incised along ventral margin, without ornamentation. Praecoxae triangular, with row of spinules distally. Coxae with one row of large spinules and one transverse row of smaller ones on anterior surface; posterior surface with row of small spinules near outer margin. Bases with plumose outer seta and with inner distal corner forming small spinous projection, with spinules along inner and distal margins and near base of outer seta. Rami 3-segmented, endopod slightly longer than exopod in P2–P3, nearly equal in length in P4. All segments with row of strong spinules along outer margin, sparse long setules present along inner margin of P2–P4 exp-1, P2–P4 exp-2 and P3 exp-3. P2–P4 enp-2 and enp-3 with pore on anterior surface. All segments of exopod and endopod, except for enp-1, with spiniform extension at outer distal corner or distal margin (exp-3 and enp-3), particularly pronounced on enp-2. Setal formula of swimming legs as follows:

P5 ( Fig. 3D View FIGURE 3 ). Baseoendopods not fused medially; rami distinct. Endopodal lobe ¾ length of exopod, with few small spinules along outer margin and one pore on anterior surface; with five elements, inner margin with two spines (proximal one smooth, distal one bipinnate) and one naked seta, distal margin with minutely bipinnate, inner seta and naked outer seta. Exopod ovoid, about 1.5 times as long as maximum width, with few spinules along inner margin and small pore on anterior surface; with five slender smooth setae, middle one longest, innermost one and outer two short, less than half the length of middle one.

Description of male. Total body length 300–370 µm (mean = 337 µm, n = 11) (excluding caudal rami). Similar to female except for urosomal segmentation and ornamentation, antennule, P1 basis, P2 endopod, P3 exp-3, P5 and caudal ramus. Genital and first abdominal somites (urosomite-2 and -3) not fused ( Fig. 4A View FIGURE 4 ). Sixth legs asymmetrical with each member represented by a plate with three smooth setae, middle one longest ( Fig. 4A View FIGURE 4 ).

Caudal ramus ( Fig. 4A View FIGURE 4 ) as in female except for seta II being less inflated in its proximal half.

Somitic ornamention ( Fig. 4A View FIGURE 4 ) as in female except for urosomite-3 and -4 each displaying a midventral row of spinules.

Antennule ( Fig. 4B–C View FIGURE 4 ) haplocer, 10-segmented; segments 4 and 6 small, partly concealed by proximal and distal portions of swollen segment 5 (in ventral aspect). Geniculation between segments 7 and 8. Segments 5–8 with modified elements; with aesthetasc on segments 5 and 10. Armature formula as follows: 1-[1 pinnate], 2-[9 + 1 pinnate], 3-[8], 4–[2], 5-[5 + 2 pinnate + (1 + ae)], 6-[1 + 1 pinnate], 7-[3 + 2 modified], 8-[2 + 1 modified], 9-[4], 10-[5 + (2 + ae)].

P1 basis ( Fig. 3E View FIGURE 3 ) anterior surface with long, bent chitinous projection near outer margin, with minutely dentate apex; inner basal spine unipinnate.

P2 endopod ( Fig. 3F View FIGURE 3 ) modified, 2-segmented. Enp-1 as in ♀ except for inner seta being shorter and with pore on anterior surface. Enp-2 elongate, drawn out into apical spinous projection; outer margin with long fine setules; anterior surface with three small pores; inner margin with two plumose setae, proximal one shorter than distal one.

P3 as in ♀ except for small, slender tube-pore on anterior surface of exp-3 ( Fig. 3G View FIGURE 3 ).

P5 ( Fig. 3H View FIGURE 3 ). Baseoendopods fused medially; endopodal lobe with two stout, bipinnate spines apically; with few spinules along outer margin and pore on anterior surface. Exopod discrete, extending beyond distal margin of endopodal lobe, about 1.2 times as long as broad; with five elements, inner two setae bipinnate, apical seta smooth and longest, and outer two setae smooth and short.

Etymology. The species is named after its type locality, Xiamen, along the south coast of China.

Variability. The P2 enp-3 of one female specimen displayed only one inner seta on one side.