Pupulina keiri, Boxshall, 2018

Boxshall, Geoff, 2018, The sea lice (Copepoda: Caligidae) of Moreton Bay (Queensland, Australia), with descriptions of thirteen new species, Zootaxa 4398 (1), pp. 1-172 : 154-160

Pupulina keiri sp. nov.

( Figs. 74–76 )

Type material. Holotype ♀, 2♀♀ paratypes, 1♂ allotype from Aetobatus ocellatus (Kuhl, 1823) (TC17932) 5 July 2016, QM Reg. Nos Holotype ♀ W53128, 2 paratype ♀♀ W53129, allotype ♂ W53130; 2♀♀, 2♂♂, 2 immature paratypes (TC17637) 27 June 2016, QM Reg. Nos 2 paratype ♀♀ W53131, 2 paratype ♂♂ W53132, 2 immatures W53133; 2♀♀, 2♂♂, 3 immature paratypes (TC17933) 5 July 2016, NHMUK Reg. Nos 2017.353–356; 2♂♂, 7 immature paratypes (TC17940) 6 July 2016, NHMUK Reg. Nos 2017.357–358.

Type Host. Aetobatus ocellatus (Kuhl, 1823) .

Site on host. Body surface.

Etymology. The new species is named after Keir Boxshall, a keen diver and observer of elasmobranchs.

Description. Adult female ( Fig. 73A ) mean body length including caudal rami 5.76 mm, range 5.54 to 5.96 mm (based on 4 ovigerous specimens). Cephalothorax subcircular, comprising about 48% of total body length; surface of dorsal cephalothoracic shield densely ornamented with sensillae near posterolateral corners ( Fig. 73B ). Free margin of thoracic portion of dorsal cephalothoracic shield extending posteriorly beyond rear margins of lateral portions. Frontal plates without lunules. Free fourth pedigerous somite wider than long. Genital complex about 1.2 times wider than long, with rounded anterolateral corners and linear lateral margins; fifth legs carried ventrolaterally near posterolateral corners ( Fig. 73C ). Copulatory pores located near midline, oviduct openings marked by swellings. Genital complex about 1.6 times longer than abdomen (including caudal rami). Abdomen elongate; about 2.2 times longer than wide. Caudal rami ( Fig. 73D ) elongate about 3.1 times longer than wide. Each ramus armed with 1 short, curved plumose seta at inner distal angle, 2 short plumose setae along distal part of lateral margin, and 3 long plumose setae on distal margin; ornamented with linear array of 4 long setules along dorsal midline and 2 short sensillae ventrally.

Antennule ( Fig. 73E ) 2-segmented; large proximal segment with 1 sensilla plus 22 plumose setae arrayed along anteroventral surface and 2 setae located dorsally; distal segment bearing 12 elements (10 setae plus 2 aesthetascs) around apex, plus isolated seta on posterior margin. Ventral cephalothoracic surface forming spinous process located immediately medial to base of antennule ( Fig. 73E ). Antenna ( Fig. 73F ) comprising proximal segment bearing pointed, posteriorly-directed spinous process; middle segment subrectangular, tapering slightly distally, unarmed; terminal segment forming recurved claw bearing seta on weak swelling proximally, and seta near anterior margin. Post-antennal process short, weakly curved; ornamented with 2 multisensillate papillae on large basal part and single multisensillate papilla on adjacent ventral cephalothoracic surface.

Mandible of typical stylet-like structure, with 12 marginal teeth. Maxillule ( Fig. 75A ) comprising anterior papilla bearing 3 unequal, tiny naked setae, and tapering posterior process with minute subapical tooth. Maxilla 2- segmented, comprising elongate syncoxa and basis ( Fig. 74A ): syncoxa unarmed; basis bearing membranous flabellum on anterior margin, and terminating in 2 claw-like elements (calamus and canna). Calamus more than twice as long as canna, both ornamented with strips of serrated membrane. Maxilliped subchelate ( Fig. 74B ); proximal segment slender with smooth myxal surface; distal subchela short, with apical claw separated from proximal segmental part by incomplete suture; slender seta present on concave margin.

Sternal furca absent.

First swimming legs biramous ( Fig. 74C ); joined by slender intercoxal sclerite; sympod with inner and outer plumose setae derived from basis; endopod 2-segmented: first segment unarmed, second with 3 plumose setae on distal and inner margins. Exopod 2-segmented; directed laterally and forming main axis of leg; first segment armed with small outer (anterior) spine and ornamented with row of setules along middle section of posterior margin; second segment armed with 3 plumose setae along posterior margin and 4 distal elements along distal margin. Distal elements as follows: spine 1 largest, slightly curved and with row of minute serrations along concave margin; spine 2 markedly longer than spine 3, without accessory process and armed with rows of minute serrations; spine 3 short, with accessory process; seta 4 plumose, about as long as spine 3, and shorter than segment; positioned on anterior surface of segment.

Second leg ( Fig. 74D ) biramous, with flattened protopodal segments and 3-segmented rami. Coxae of leg pair joined by elongate intercoxal sclerite bearing extensive marginal membrane posteriorly. Coxa with plumose seta and surface bisensillate papilla. Basis armed with outer naked seta; ornamented with surface bisensillate papilla near origin of endopod, marginal membrane posteriorly, and flap of membrane anteriorly, reflexed back over dorsal surface of segment. First exopodal segment with bilaterally serrate outer spine directed obliquely across surface of ramus, plus inner plumose seta, and bearing anterior flap of membrane reflexed back over dorsal surface of ramus; second segment with shorter bilaterally serrate spine aligned with long axis of ramus, plus inner seta; third segment with proximal and distal naked outer spines, apical spine ornamented with pinnules bilaterally, and 5 inner plumose setae. First and second endopodal segments armed with 1 and 2 inner plumose setae, respectively; both segments with expanded lateral margins ornamented with setules: third segment with 6 plumose setae.

Third leg pair ( Fig. 75B ) forming flattened plate closing posterior part of cephalothoracic sucker. Protopodal part flattened and joined by plate-like intercoxal sclerite forming apron, ornamented with marginal membrane posteriorly and along lateral margin anterior to exopod; bearing inner plumose seta at junction with intercoxal plate, and outer plumose seta near base of exopod; sensillae located adjacent to inner coxal seta and adjacent to origin of endopod and scattered over surface; rami originating close together. Exopod 3-segmented ( Fig. 75C ); first segment armed with straight outer spine and inner plumose seta, plus pecten at outer distal corner of segment; second segment armed with outer spine and inner seta; third segment with 3 short outer spines and 4 plumose setae along distal and inner margins. Endopod 3-segmented; first segment with enlarged lateral margin forming subcircular velum ornamented with spinules along free margin, lacking inner seta; second segment with 2 plumose inner setae; third segment with 4 plumose setae.

Fourth leg ( Fig. 75D ) 4-segmented, comprising robust protopodal segment and 3-segmented exopod: protopodal segment ornamented with scattered surface spinules and armed with plumose seta distally; first and second exopodal segments each armed with stout outer distal spine with pecten at base; third with long apical spine and 2 shorter spines, one set subapically on lateral margin; spines ornamented with serrated membrane bilaterally; large pecten present at inner distal corner.

Fifth legs developed as conspicuous tapering posterior processes originating posterolaterally on genital complex ( Fig. 73C ); each fifth leg comprising isolated anterior seta (outer protopodal seta) located on surface of genital complex and small posterior papilla representing exopod, armed with 2 plumose setae.

Allotype male ( Fig. 76A ) mean body length including caudal rami 4.17 mm, range 4.04 to 4.44 mm (based on 6 specimens). Cephalothorax subcircular as in female. Genital complex ( Fig. 76B ) about 1.4 times longer than wide, measured along mid-line; with linear lateral margins; ventral surface ornamented with spinules. Abdomen long, 2-segmented; first somite distinctly shorter than second ( Fig. 76C ), ornamented with surface sensillae; carrying paired caudal rami distally; anal slit terminal. Caudal rami about 3.8 times longer than wide, ornamented with sensillae on ventral surface; armed with short plumose seta at inner distal angle, 2 short plumose setae on distal part of lateral margin, and 3 long plumose setae around distal margin.

Antennule, mandible and maxilla as in female. Antenna modified ( Fig. 76D ); first segment elongate; second segment reflexed, swollen proximally with surface forming corrugated adhesion pads ventrally, plus dorsal pad in distal part; distal segment forming short powerful apical claw, with accessory claw and armed with 2 setae proximally. Maxillule ( Fig. 76E ) similar to that of female but with small, rounded post-oral process present, plus additional knob-like process on surface sclerite anterior to posterior process.

Maxilliped ( Fig. 76F ) slender, proximal segment bearing small spiniform process on myxal margin; distal subchela longer than in female.

Spines on exopod of leg 2 modified in adult male: outer spine on second exopodal segment and proximal outer spine on third segment both stout and ornamented distally with dual rows of rounded denticles ( Fig. 76G ). Distal outer spine on third segment about as long as other spines, stout, unornamented.

Fifth legs 5 ( Fig. 76B ) represented by isolated plumose seta plus posterior lobe bearing 2 plumose setae located ventrolaterally almost at mid-level of genital complex. Sixth legs each represented by oblique operculum closing off genital aperture and armed with 3 short naked setae around apex ( Fig. 76B ).

Remarks. Only five genera of Caligidae retain a 2-segmented endopod of leg 1 armed with 0-0; 3 setae: Alebion , Avitocaligus Boxshall & Justine, 2005 , Euryphorus Milne Edwards, 1840 , Gloiopotes and Pupulina van Beneden, 1892 . Pupulina can be distinguished from these other four by the combination of the loss of the endopod of leg 4 ( Euryphorus and Avitocaligus have a biramous leg 4 with a 2-segmented endopod), and the lack of paired dorsal plates on the fourth pedigerous somite (dorsal plates are present in Alebion , Euryphorus and Gloiopotes ). Pupulina currently comprises five valid species: P. flores van Beneden, 1892 , P. brevicauda M.S. Wilson, 1952 , P. minor M.S. Wilson, 1952 , P. cliffi Dippenaar & Lebepe, 2013 and P. merira Dippenaar & Lebepe, 2013 , and these species can be identified using the key provided by Dippenaar & Lebepe (2013). The new species and P. cliffi both lack paired posterolateral processes on the female genital complex, while in P. merira , the posterolateral corners of the genital complex of the female are very slightly expanded and were considered to represent short, rounded processes by Dippenaar & Lebepe (2013). The other three species each have paired posterolateral processes that reach at least to the middle of the first free abdominal somite.

Female P. merira have elongate caudal rami that are about 6.7 times longer than maximum width (at base) and are almost as long as the abdomen. In the new species, the caudal rami are about 3.1 times longer than wide and less than half the length of the abdomen. In addition, the second exopodal segment of leg 4 carries a plumose inner seta as well as an outer spine, whereas in P. kieri sp. nov. this segment carries only an outer spine.

The new species is most closely related to P. cliffi which was described from two species of mobuline rays, Mobula kuhlii (Müller & Henle, 1841) and M. eregoodootenkee (Bleeker, 1859) caught in South African waters (Dippenaar & Lebepe, 2013). In P. cliffi the caudal rami are about 5.3 times longer than wide whereas in P. kieri sp. nov. the caudal rami are about 3.1 times longer than wide. The abdomen in P. cliffi is about as long as the genital complex and is 3.8 times longer than wide, in contrast in the new species the abdomen is less than half the length of the genital complex and is only 2.3 times longer than wide. These differences are sufficient to justify the establishment of a new species to accommodate the material from Moreton Bay.

All previous records of this genus are from rays belonging to the subfamily Mobulinae (family Myliobatidae ): P. flores on Manta birostris (Walbaum, 1792) ( C.B. Wilson, 1935; M.S. Wilson, 1952) and? Mobula hypostoma (Bancroft, 1831) (Bere, 1936) , P. brevicauda from Mobula thurstoni (Lloyd, 1908) (as M. lucasana Beebe & Tee- Van) ( Wilson, 1952) and M. mobular (Bonnaterre, 1788) (as M. diabolus (Shaw)) ( Pillai & Padmanbhan, 1963) , P. minor also from M. thurstoni (as M. lucasana ) ( Wilson, 1952) and M. mobular (as M. diabolus ) ( Pillai, 1964b), and both P. cliffi and P. merira from M. kuhlii and M. eregoodootenkee (Dippenaar & Lebepe, 2013) . The host of the new species from Moreton Bay is Aetobatus ocellatus , a member of the subfamily Myliobatinae . This marks a considerable broadening of the known host range of Pupulina .

Figures

FIGURE 75. Pupulina keiri sp. nov. paratype female. A, maxillule; B, leg 3, ventral; C, exopod of leg 3, ventral; D, leg 4. Scale bars:100 µm on A, 0.5 mm on B, 200 µm on C, D.

FIGURE 76. Pupulina keiri sp. nov. paratype male. A, habitus, dorsal; B, genital complex, ventral view; C, free abdominal somites and caudal ramus, ventral; D, antenna; E, maxillule and postoral process; F, maxilliped; G, sexually dimorphic spines on outer margin of exopod of leg 2.Scale bars:1.0 mm on A, 0.5 mm onB, 200 µm on C, F, 100 µm on D, E, G.

FIGURE74. Pupulina keiri sp. nov. paratype female. A, maxilla;B, maxilliped; C, leg 1 and interpodal bar, anterior;D, leg 2, ventral. All scale bars 200 µm.

FIGURE73. Pupulina keiri sp. nov. paratype female.A, habitus, dorsal;B, left corner of dorsal cephalothoracic shield, dorsal view showing surface ornamentation; C, genital complex, ventral view with spermatophore attached; D, caudal ramus, ventral; E, antennule and adjacent hookon ventral cephalothoracic surface,drawn in situ; F, antennaand post-antennal processdrawn in situ. Scale bars:1.0 mm on A, 0.5mm on B,200 µm on C–F.