Pseudionella pumulaensis Williams & Landschoff, 2024

(SOSA), Senckenberg Ocean Species Alliance, Brandt, Angelika, Chen, Chong, Engel, Laura, Esquete, Patricia, Horton, Tammy, Jażdżewska, Anna M., Johannsen, Nele, Kaiser, Stefanie, Kihara, Terue C., Knauber, Henry, Kniesz, Katharina, Landschoff, Jannes, Lörz, Anne-Nina, Machado, Fabrizio M., Martínez-Muñoz, Carlos A., Riehl, Torben, Serpell-Stevens, Amanda, Sigwart, Julia D., Tandberg, Anne Helene S., Tato, Ramiro, Tsuda, Miwako, Vončina, Katarzyna, Watanabe, Hiromi K., Wenz, Christian & Williams, Jason D., 2024, Ocean Species Discoveries 1 – 12 — A primer for accelerating marine invertebrate taxonomy, Biodiversity Data Journal 12, pp. e 128431-e 128431 : e128431-

Pseudionella pumulaensis Williams & Landschoff sp. nov.

" undescribed Pseudionella sp. ": Landschoff et al. (2018): 2, 12: figs. 6 D, 14.

Materials

Type status: Holotype. Occurrence: catalogNumber: SAMC-A 096401 ; occurrenceRemarks: infesting left branchial chamber of male Pagurus fraserorum Landschoff & Komai in Landschoff et al., 2018 (2.4 mm shield length; SAMC-A 066407); recordedBy: Jannes Landschoff; individualCount: 1; sex: female; lifeStage: adult; reproductiveCondition: egg-bearing; preparations: 96 % EtOH; occurrenceID: 04AA858B-3D1B-51FB-8E57-FCE19D28C43C; Taxon: scientificName: Pseudionella pumulaensis Williams & Landschoff ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Bopyridae ; genus: Pseudionella ; specificEpithet: pumulaensis ; taxonRank: species; scientificNameAuthorship: Williams & Landschoff; nomenclaturalCode: ICZN; Location: higherGeography: Indian Ocean; continent: Africa; country: South Africa; stateProvince: KwaZulu-Natal; locality: off Pumula ; verbatimDepth: 20 m; verbatimLatitude: S 30 ° 38.34 ’; verbatimLongitude: E 30 ° 32.94 ’; Identification: identifiedBy: J. D. Williams, J. Landschoff; Event: samplingProtocol: SCUBA; eventDate: 14 / 10 / 2015; habitat: rocky subtidal reef; Record Level: institutionCode: SAMC; basisOfRecord: PreservedSpecimen

Type status: Paratype. Occurrence: catalogNumber: SAMC-A 096402 ; recordedBy: Jannes Landschoff; individualCount: 1; sex: male; lifeStage: adult; preparations: 96 % EtOH; occurrenceID: F2F76206-2B7A-5616-95A0-4694C9BDAE05; Taxon: scientificName: Pseudionella pumulaensis Williams & Landschoff ; kingdom: Animalia; phylum: Arthropoda; class: Malacostraca; order: Isopoda ; family: Bopyridae ; genus: Pseudionella ; specificEpithet: pumulaensis ; taxonRank: species; scientificNameAuthorship: Williams & Landschoff; nomenclaturalCode: ICZN; Location: higherGeography: Indian Ocean; continent: Africa; country: South Africa; stateProvince: KwaZulu-Natal; locality: off Pumula ; verbatimDepth: 20 m; verbatimLatitude: S 30 ° 38.34 ’; verbatimLongitude: E 30 ° 32.94 ’; Identification: identifiedBy: J. D. Williams, J. Landschoff; Event: samplingProtocol: SCUBA; eventDate: 14 / 10 / 2015; habitat: rocky subtidal reef; Record Level: institutionCode: SAMC; basisOfRecord: PreservedSpecimen

Description

Female holotype (Figs 18 , 19 ) body length 3.4 mm, maximum width 1.8 mm, head length 0.5 mm, head width 0.7 mm, pleon length 1.1 mm. Body tear-drop-shaped (Fig. 18 B and C, Fig. 19 A and B), approximately symmetrical, head slightly sinistrally rotated (<5 °). Very small patches of pigment present on some Prn (Fig. 19 A).

Head subquadrate (Fig. 19 A) with slight medial indentation at anterior end, narrow frontal lamina extending slightly beyond lateral margins of head. Small eyes near posterolateral corners of raised lamina edge. Barbula with two pairs of small, smooth rounded lobes (Fig. 19 C). A 1 (Fig. 19 E) of three art each, extending beyond anterior margin of head; A 2 (Fig. 19 E) of three art each, but basal art broadly rounded and fused with head (see Remarks); all art of A 1 and A 2 with spinous scales and distal setae. Mxp (Fig. 19 H) anterior lobe broad, rounded, with unarticulated palp with few large setae and many fine setae, lateral edge of lobe setose; posterior lobe with small rounded spur.

Prn (Fig. 19 A) of seven Prn, broadest across Prn 3, tapering anteriorly and posteriorly. Small coxal plates on sides of pereomeres all similar, but larger on left side of body; dorsolateral bosses on Prn 1 – Prn 4. First oostegite anterior lobe ovate, posterior lobe subtriangular, internal ridge smooth (Fig. 19 F and G). Oostegites 3–5 with some minute circular tubercles; oostegite 5 with fringe of setae on posterior margin (Fig. 19 B). P 1–7 (Fig. 19 I, J) slightly increasing in size posteriorly and of similar morphology, small curved dactylus, ovate propodus indistinctly separated from triangular carpus, small triangular merus, elongate ischium and subquadrate basis; all art with spinous scales, propodus with few small setae on anterolateral margin, carpus with stout setae at anterior tip (Fig. 19 I and J).

Pleon (Fig. 19 B and D) of six Pl. Pl 1 – Pl 5 with uniramous, digitiform Plp (Fig. 19 B and D), first two Plp with indentation giving appearance of biramous morphology, but each a single lobe (possible fusion of endopod and exopod); uniramous rounded lateral plates (Fig. 19 B and D); lateral plates and Plp reduced in size from anterior to posterior. Plt (Fig. 19 B and D) with sixth pair of lateral plates projecting laterally and pair of large broad, distally rounded uniramous uropods.

Eggs (Fig. 19 B) approximately 195 in number, a few potentially lost in transfer, 150.3 ± 9.9 µm in diameter (n = 30).

Male paratype (allotype) (Fig. 20 ) body length 1.3 mm, maximum width 0.7 mm, head length 0.2 mm (not including Prn 1), head width 0.4 mm, pleon length 0.3 mm. Body suboval-shaped, squat. Small, irregular patches of dark pigmentation on nearly all Prn.

Head fused with Prn 1, anterior margin of head broadly rounded (Fig. 20 A), irregularly-shaped eyes near posterolateral margin. A 1 of three art each; A 2 of five art each, extending slightly beyond margin of head; A 2 and A 1 with few spinous scales and distal setae (Fig. 20 C).

Pereon of seven Prn, broadest across pereomere 4, tapering anteriorly and posteriorly. Lateral margins of Prn 1–3 directed anteriorly, Prn 4–7 directed posteriorly. P 1 (Fig. 20 C) largest, slightly decreasing in size posteriorly; all art distinct, curved dactylus with minute setae, ovate propodus, subquadrate carpus, elongate merus and ischium, small subquadrate basis; all art with spinous scales, propodus scales and spines adjacent to dactylus plus few setae on anterolateral margin, carpus with stout setae at anterior tip; P 7 (Fig. 20 D) similar in morphology to P 1, except dactylus shorter and carpus more triangular in shape.

Pleon (Fig. 20 D) of six Pl, markedly narrower than pereon, Pl tapering posteriorly, all Pl distinctly segmented and bearing lateral plates, Pl 1–4 with pleopods indistinctly separated from lateral plates, Pl 5 with broad, rounded lateral plates; no mid-ventral tubercles (Fig. 20 D). Plt (Fig. 20 D) notched medially with anal cone, produced distolaterally into rounded lobes, with scales and setae; Urp absent.

Diagnosis

Female body nearly straight, barbula with two small, smooth lobes on each side, all pleopods uniramous. Male head fused with pereomere 1, antennulae and antennae of 3 and 5 articles, respectively.

Etymology

The specific epithet pumulaensis refers to the locality of Pumula in KwaZulu-Natal, South Africa, where the species was first discovered. The word Pumula is Zulu and means " a place of rest ".

Distribution

KwaZulu-Natal, east coast of South Africa (Indian Ocean); rocky subtidal reef.

Ecology

Host: Pagurus fraserorum Landschoff & Komai in Landschoff et al. (2018) ( Crustacea, Decapoda, Anomura , Paguridae Latreille, 1802 ), a hermit crab described from KwaZulu-Natal, South Africa. Parasite location on host: Branchial chamber (gill-parasitic). See Fig. 18 and Landschoff et al. (2018), page 14.

Only one out of nine specimens of Pagurus fraserorum Landschoff & Komai in Landschoff et al. (2018) was found parasitised by P. pumulaensis sp. nov. (11 % overall prevalence). An additional specimen of P. fraserorum was reported by Landschoff et al. (2018) to have another branchial parasitic isopod (provisionally identified as Pseudionella sp. ); unfortunately, that specimen no longer exists.

Taxon discussion

Formerly, Pseudionella was known to contain five species, which parasitise diogenid (1 species) and pagurid (4 species) hermit crabs from the South Pacific Ocean, North Pacific Ocean, North Atlantic Ocean, Caribbean Sea and South China Sea ( Shiino 1949, Adkison and Heard 1978, Bourdon 1979, Boyko and Williams 2001, An et al. 2013). The new species of Pseudionella described herein parasitising Pagurus fraserorum Landschoff & Komai in Landschoff et al. (2018) is the first reported from the genus on hermit crabs from the Indian Ocean.

Pseudionella pumulaensis Williams & Landschoff , sp. nov. can be distinguished from the previously described species ( P. akuaku Boyko & Williams, 2001 , P. attenuata Shiino, 1949 , P. deflexa Bourdon, 1979 , P. markhami ( Adkison & Heard, 1978) and P. spiropaguri An, Li & Markham, 2013 ), based on several characters. In contrast to females of P. akuaku , P. attenuata , P. deflexa and P. markhami , which are highly asymmetrical (dextral or sinistral deflexion of the head), P. pumulaensis and P. spiropaguri are nearly straight. In overall body form of females and males, P. pumulaensis and P. spiropaguri appear most similar, but can be distinguished, based on the following characters: barbula morphology (two small, smooth lobes on each side in P. pumulaensis vs. three lobes with digitate tips on each side in P. spiropaguri ), female pleopod morphology (all uniramous in P. pumulaensis vs. first three biramous in P. spiropaguri ), male antennae morphology (antennules and antennae of 3 and 5 articles, respectively in Pseudionella pumulaensis vs. 3 and 4 articles in P. spiropaguri ) and male head fusion (fused with pereomere 1 in P. pumulaensis vs. separated in P. spiropaguri ).

Notes

Methods

Hermit crabs containing the bopyrid isopod specimens were sampled under the University of Cape Town Science Faculty collection permit and Animal Ethics Committee approval, protocol number 2014 / DC 1 / CLG. The host specimens of Pagurus fraserorum were all collected during two days of SCUBA diving on near-shore reefs off Pumula and Hibberdene, approximately 100 km south of Durban, KwaZulu-Natal, South Africa. Live pictures were taken after the process of anaesthetising (> 10 min in 0.125 ml / l clove oil-seawater solution), freezing and thawing of the specimens. Thereafter, specimens were preserved in 96 % ethanol.

Line drawings of the parasite bopyrid isopods were made by using camera lucida drawing tubes attached to Olympus compound (Olympus CX 41) and dissecting microscopes (Olympus sZX 12). Adobe Illustrator and a Wacom Cintiq pen display were used to trace original sketches and produce final figures. Parasite sizes are given as maximum total length (TL). All specimen measurements were made from camera lucida drawing tube sketches and slide micrometers. Morphological terminology follows that of Boyko and Williams (2001) and An et al. (2013). Specimens of the new species were deposited at the Iziko South African Museum, Cape Town, South Africa ( SAMC).

Figures

Figure 18. Live image of Pagurus fraserorum Landschoff & Komai in Landschoff et al., 2018 and Pseudionella pumulaensis Williams & Landschoff, sp. nov. A. Dorsal view of P. fraserorum with inflated left branchial chamber; B. Left lateral view with branchial chamber showing P. pumulaensis sp. nov.; C. Close-up view of B. Scale bars: 2 mm (A, B), 1 mm (C).

Figure 19. Pseudionella pumulaensis Williams & Landschoff, sp. nov., adult female holotype (SAMC A 096401). A. Habitus, dorsal view; B. Habitus, some eggs shown in dashed lines, ventral view; C. Right barbula; D. Pleon, right lateral view; E. Right antennule, antenna and mouthparts, ventral view; F. Right oostegite 1, internal view; G. Right oostegite 1, external view; H. Right maxilliped, external view; I. Left pereopod 1; J. Left pereopod 7. Abbreviations: A 1 = antennula, A 2 = antenna, Mo = mouthparts, Pl 1 – Pl 5 = pleomeres 1–5, U = uropod. Scale bars: 500 µm (A, B), 250 µm (C, D, F, G), 50 µm (E, H – J).

Figure 20. Pseudionella pumulaensis Williams & Landschoff, sp. nov., adult male paratype (allotype) (SAMC A 096402). A. Habitus, dorsal view; B. Habitus, ventral view; C. Left antennula, antenna, mouthparts and pereopod 1, ventral view; D. Left pereopod 7 and pleon, ventral view. Abbreviations: A 1 = antennule, A 2 = antenna, Mo = mouthparts, P 1 = pereopod 1, P 7 = pereopod 7, Pl 1 – Pl 5 = pleomeres 1–5. Scale bars: 250 µm (A, B), 50 µm (C, D).