Pontella mayalibit, Margarethasidabalok & Mulyadi, 2024

Margarethasidabalok, Conni & Mulyadi, Hanung Agus, 2024, A New Species of Pontella Dana, 1846 and New Record of Pontella surrecta Wilson (1950) (Copepoda, Calanoida, Pontellidae) from Indonesian Waters, with Notes on Their Species-Groups, Zootaxa 5512 (4), pp. 553-566 : 555-561

publication ID	https://doi.org/ 10.11646/zootaxa.5512.4.5
publication LSID	lsid:zoobank.org:pub:4947E5E1-AC6B-46AC-802D-14A1123192F2
persistent identifier	https://treatment.plazi.org/id/583F4255-FFB1-4214-FF29-FEC62103F85C
treatment provided by	Plazi
scientific name	Pontella mayalibit
status	sp. nov.

Treatment

Pontella mayalibit n. sp.

urn:lsid:zoobank.org:act:105E3657-8BD1-4D5F-92E7-D80BDC669530

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

Pontella alata A. Scott, 1909 View in CoL , Mulyadi, 2014a:34–39, figs. 2–3.

Material examined. All same locality. Holotype: MZB. Cr.Cop. 208, ♀ (3.60 mm) ; Paratype: MZB. Cr.Cop. 131 (elevated from non-type material in Mulyadi, 2014a), 20 ♀ (3.55–3.65 mm), 20 ♂ (3.43–3.47 mm), Mayalibit Bay, Raja Ampat , West Papua (01°15’N 123°37’E), 8 June 2007, surface tow of 0.33 mm mesh plankton net, coll: Conni M. Sidabalok GoogleMaps .

Holotype description

Female. Body ( Fig. 1a View FIGURE 1 ) robust, relative length of prosome to urosome 3.5:1. Cephalosome separated from Pdg1; Pdg4 and Pdg5 distinct; posterior corners of prosome produced into asymmetrical, short acuminate processes with globular base in dorsal view, left process slightly longer than right, reaching about one third length of genital compound somite. Cephalosome bluntly triangular with a pair of lateral hooks and a pair of lenses located anteriorly. Rostrum ( Fig. 1f View FIGURE 1 ) bifurcate, symmetrical, thickened basally and tapering distally, directed ventrally, without lens, basal portion extended ventrally, roughly to level of ventral eye and divided distally into two short spiniform processes.

Urosome ( Figs. 1b–e View FIGURE 1 ) 2-segmented. Genital compound somite larger than anal somite; asymmetrical, left side with large posterodorsal beak-like elevation ( Fig. 1a View FIGURE 1 ), latter elevation arising halfway along length of genital compound somite, directed dorsocaudally and tapering into rounded tip reaching as far as posterior end of genital compound somite. Operculum over genital opening extended to right side forming spiniform process. Caudal rami extremely asymmetrical, right caudal ramus much broader and longer than left, and not completely fused with anal somite; inner margin of each ramus fringed with fine hairs; each ramus with seta I rudimentary and naked, setae II– VI thickened proximally, enlarged portion of seta distinctly shorter than ramus.

Antennule ( Fig. 1g View FIGURE 1 ) 25-segmented, symmetrical, extending to middle of Pdg3; posterior margin of segments 2–12 fringed with fine hairs; ancestral segments III – V and VIII –IX incompletely fused, segments XXVII – XXVIII completely fused. Fusion pattern and setal formula as follows: (I)-2 + ae; ( II)-1sp; ( III – V)-4 + ae; ( VI)-2 + ae; ( VII)- 2 + ae; ( VIII-IX)-4 + ae; (X)-2 + ae; ( XI)-2 + ae; ( XII)-2 + ae; ( XIII)-2 + ae; ( XIV)-2 + ae; ( XV)-2 + ae; ( XVI)-2 + ae; ( XVII)-1 + sp + ae; ( XVIII)-2 + 1; ( XIX)-1+ sp + ae; ( XX)-2 + ae; ( XXI)-2 + ae; ( XXII)-1; ( XXIII)-1; ( XXIV)-1 + sp; ( XXIV)-1 + sp; ( XXV)-1 + sp + ae; ( XXVI)-1s + 1s + 1ae; ( XXVII – XXVIII)-6 + ae.

Antennae ( Fig. 2a View FIGURE 2 ) biramous, with coxa having plumose seta proximally, basis with 2 anterodistal setae; Ri 2-segmented, proximal segment completely fused with basis, much elongated, bearing 2 setae of unequal length distally, apical segment lamellar, produced into proximal and terminal lobes, former with 6 long and 3 minute setae, the latter with setula, 6 setae, and proximal fine spinules; Re 5-segmented, 2nd segment cylindrical, with seta at 1/6 of its length, medial seta, and 3 distal setae; terminal segment globular, equipped with 2 setulae and one seta.

Mandibular blade ( Fig. 2c View FIGURE 2 ) heavily chitinized bearing 7 teeth and spinulose seta on cutting edge; both 3rd and 4th dorsal most teeth bicuspidate; “dagger like” spines ( Turner, 1978) present at base of teeth 3–7. Mandibular palp ( Fig. 2b View FIGURE 2 ) with 2-segmented Ri and 5-segmented Re; basis bearing 4 inner marginal setae.

Maxillula ( Fig. 2d View FIGURE 2 ) with gnathobase having 16 stout setae, minute spinules and fine hairs near base of stout setae; 2nd inner lobe with 3 setae of unequal length; 3rd inner lobe with 1 long and 3 short setae of sub-equal length; 1st outer lobe equipped with 9 setae; 2nd outer lobe rudimentary with single seta; basis with 2 long hairs on inner basal half, 4 medial setae, 4 sub-apical setae and 5 apical setae; Ri completely fused with basis; Re with 10 setae and small setula.

Maxilla ( Fig. 2e View FIGURE 2 ) with 6 inner lobes on basal segment; lobes 4–6 carrying 2, 1 and 1 strong setae, respectively, each with row of setulae arranged at right angles to its inner margin and distal end serrated; Ri of 3 segments, 1st segment with only single strong seta, 2nd with setula and strong seta, 3rd segment with 3 strong setae, one of which being serrate along inner margin.

Maxilliped ( Fig. 2f View FIGURE 2 ) uniramous, reduced in size; precoxa and coxa completely fused, with 3 groups of setae, consisting of 2, 3 and 3 setae, respectively, distal part produced distally covering basal part of basis; anterior margin of basis fringed with row of small teeth and small setula subdistally and 2 plumose setae distally; endopod 5- segmented, with setal formula 2, 1, 1, 1, 3.

P1–P4 ( Figs. 3a–d View FIGURE 3 ) biramous, coxa and basis each 1-segmented, basis with 1 plumose seta on inner side; Re 3- segmented, Ri 3-segmented in P1 and 2-segmented in P2–P4. Number of setae and spines on P1–P4 as follows:

P5 ( Fig. 3e View FIGURE 3 ) asymmetrical; each basis with plumose seta near base of posterior face; left Re 1.4 length of right, smoothly curved inward, tapering to distal point, with 2 minute processes along outer margin; left Ri also longer than right; right Re virtually naked, Ri short, about 0.35 length of Re; both Ri bifurcated.

Male. Body ( Fig. 4a View FIGURE 4 ) more compact than that of female. Cephalosome and Pdg1 separated; Pdg4 and Pdg5 fully divided; posterior corners of prosome produced into asymmetrical, short and pointed processes, with globular base in dorsal view, reaching middle length of genital somite. Pair of cephalic hooks as in female ( Fig. 4b View FIGURE 4 ). Dorsal eye lenses larger than those of female. Rostrum ( Fig. 4c View FIGURE 4 ) bulbous with bifurcated, short conical projections, with 2 well-developed- lenses, which are absent in female.

Urosome ( Fig. 4a View FIGURE 4 ) 5-segmented, genital somite somewhat asymmetrical, left side weakly produced; Ur3 longer than following 2 somites combined; caudal rami asymmetrical, rather elongated, inner margin of each ramus fringed with fine hairs, each ramus with seta I rudimentary and naked, setae II– VI without proximal thickening.

All other appendages, except for right A1 and P5, similar in structure to those of female. Right antennule ( Fig. 4d View FIGURE 4 ) geniculate, left one resembles that of female, indistinctly 12-segmented; segments II– IV, XXI – XXIII, XXIV – XXVI, XXVII – XXVIII completely fused; segments V –IX, X– XIV, XV – XVI incompletely fused. Fusion pattern and seta formula as follows: I, 3 + ae; II– IV, 4 + ae; V –IX, 10 + 3ae; X– XIV, 10 + 3ae; XV – XVI, 4 + 2ae; XVII, 2 + ae; XVIII, 2 + ae; XIX, 1 + ae; XX, 1 + p (process); XXI – XXIII, 2 + 3p + ae; XXIV – XXVI, 6 + ae; XXVII – XXVIII, 4 + ae. Fused segment XV – XVI with very strong hooked spine, segment XX with toothed ridge provided with serrated denticles; compound segments XXI – XXIII provided with falcate process distally and 2 toothed plates, proximal plate with acuminate teeth and distal one with lamelliform teeth.

P5 ( Fig. 4e View FIGURE 4 ) uniramous, asymmetrical; each basis with 1 plumose seta on posterior surface; right leg, Re1 (chela) more or less rectangular, with a slender and elongated thumb-like process, curved inward with 1 short spine on proximal corner externally; concave surface with 1 large and stout digitiform process and 1 naked seta at base; Re2 (finger) elongated almost as long as left leg, curved outward at middle point, and ending in spatulate structure, 4 short setae present along concave surface (1 seta at apex, 2 situated near base of finger and another one near distal end). Left leg, Re1 with small knob-like process at proximal end of inner margin; Re2 bulb-shaped, apex with 2 unequal spine-like processes, and 1 long flagellar process, inner margin of Re2 hirsute.

Etymology. The species name is derived from the type-locality, Mayalibit Bay, and used as a name in apposition.

Remarks. Pontella mayalibit n. sp. was collected at Mayalibit Bay in Raja Ampat, West Papua, Indonesia in a large number more than 100 captured individuals. The new species belongs to the Pontella alata group of Fleminger (1957), at present consisting of three species, P. alata Scott, 1909 (including the junior synonym P. cerami ), P. surrecta , and P. rostracticauda Ohtsuka et al. 1987 , in which the first two species are distributed in Indonesian waters. Characteristics of this group, with some emendations, as follows: (1) the posterior corners of the prosome of both sexes protruded posteriorly into a pointed tip; (2) the female rostral lens absent; (3) the female genital compound somite bearing a small or large beak-like process extending or not extending posteriorly over part to all of CR, (4) the female operculum over genital opening extended to right forming a spiniform process, (5) the right CR of the female is extremely larger than the left ramus, separated or not fully separated from anal somite, (6) the rostrum of the female is large but lacking distinctive lens, (7) the female fifth legs are asymmetrical, the right leg is shorter than the left leg, the right Re is virtually naked, lateral processes, when present are minute, (8) the rostrum of the male with large double convex lens, (9) the chela of right P5 is large with its overall width approximately equals the length of urosome and CR, (10) the distal segment of the chela of the male is slender and elongated, (11) the thumb of the right P5 of the male is slender and elongated with a slender or stout digitiform process straight or bent and paralleling thumb, (12) the terminal segment of P5 has a robust spiniform process and one large aesthete-like seta, with its inner margin ribbed (see Table 1 for more comparison with other Pontella species groups).

Pontella mayalibit n. sp. which previously was identified as P. alata by Mulyadi (2014a) is distinguishable from all the species of this group in both sexes by (1) the posterior corners of Pdg5 produced into asymmetrical short acuminated processes (vs. produced into asymmetrical long acuminated processes), (2) the female left genital compound somite with a small and rounded tip posterodorsal beak-like projection extending posteriorly to posterior end of its segment (vs. with a large beak-like and acuminate tip projection extending posteriorly over part to all of CR), (3) the female right CR not fully separated from the anal somite (vs. the right CR completely separated from the anal somite), (4) the female CR asymmetrical, right ramus extremely longer and wider than left (vs. right ramus slightly longer and wider than left). The male of P. mayalibit n. sp. is easily distinguished from other species of Pontella by the presence of the slender and elongated thumb and the stout digitiform process on concave surface of Re1 (chela) and with the Re2 (finger) of the right P5 is being slender, elongated and pointed.

Published records of the Pontella alata -group are restricted to inshore of the tropical region between eastern Australia and southern Japan ( Ohtsuka et al. 1987). Pontella mayalibit n. sp. is known at present only from the type locality Mayalibit Bay, easternmost Indonesian waters which is within the span of the Pontella alata group distribution.