Lissodelphys tahitiensis, Kim & Boxshall, 2020

Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), Megataxa 4 (1), pp. 1-6 : 629-631

Lissodelphys tahitiensis gen. et sp. nov.

( Fig. 426 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21449 ) and dissected paratypes (2 ♀♀, figured) from Lissoclinum fragile (Van Name, 1902) (MNHN-IT-2008- 4978 = MNHNA 2/ LIS /31), Papeete port, Tahiti, Monniot coll., June 1984.

Etymology. The name of the new species is based on the type locality, Tahiti.

Descriptionoffemale. Body ( Fig. 426A ) vermiform, cylindrical, unsegmented, slightly tapering anteriorly and posteriorly. Body length 3.94 mm; greatest body width 0.65 mm across mid-region. Body surface with numerous, fine, transversewrinkles ( Fig. 426B, C ) butlacking setules or spinules. Cephalic region narrowed. Posterior end of body with deep medial incision, abruptly flattened so that anterior boundary superficially appearing as articulation ( Fig. 426C ).

Rostrum ( Fig. 426D ) distinct, muchwiderthanlong. Antennule ( Fig. 426D ) as small lobe, as long as wide, bearing 9 small setae (4 on anterior margin and 5 distally) of similar length. Antenna ( Fig. 426E ) 3-segmented, consisting of coxa, basis, and unsegmented endopod; coxa and basis unarmed; endopod slightly shorter than basis: armed with 4 small setae distally plus small terminal claw, as long as adjacent setae.

Labrum not confirmed. Mandible ( Fig. 426F ) consisting of coxa and palp; coxal gnathobase elongate with simple, slightly broadened, pectinate medial margin: palp biramous; short outer lobe (exopod) with 4 setae; longer inner lobe (basis plus endopod) with traces of 2 articulations on medial side and 5 setae of unequal sizes, grouped as 1 and 4 (lacking seta on original basis region). Maxillule ( Fig. 426G ) as small lobe lacking any trace of articulation and armed with 6 setae (medial 2 setae distinctly smaller than others). Maxilla ( Fig. 426H ) indistinctly 2-segmented and armedwith 5 setae (2 on first segment and 3 on second); distalmost seta plumose. Maxilliped ( Fig. 426I ) as small lobe bearing 3 small setae apically. Legs absent.

Male. Unknown.

Remarks. Lissodelphys tahitiensis gen. et sp. nov. closely resembles L. guadeloupensis gen. et sp. nov.: they both have the same body shape and exhibit the same setation patterns on the mandible, maxilla and maxilliped. The most significant differences between the two are in the maxillule, which is incompletely 2-segmented and armedwith 8 setaein L. guadeloupensis gen. etsp. nov., whereas it is unsegmented and armed with only 6 setae in L. tahitiensis gen. et sp. nov. Additional minor differences include: the body surface is smooth in L. guadeloupensis gen. et sp. nov. butrugose in L. tahitiensis gen. et sp. nov., and the setae on the inner lobe (basis + endopod) of the mandible are arranged as 1, 1, and 3 in L. guadeloupensis gen. et sp. nov. but as 0, 1, 4 in L. tahitiensis gen. et sp. nov. These two species inhabit the same host species, Lissoclinum fragile , but were found in different zoogeographic regions.

Figures

FIGURE 426. Lissodelphys tahitiensis gen. et sp. nov., female. A, habitus, ventral; B, cephalic region, dorsal; C, posterior end of body, ventral; D, rostrum and left antennule, ventral; E, antenna; F, mandible; G, maxillule; H, maxilla; I, maxilliped. Scale bars: A, 0.5 mm; B, C, 0.05 mm; D, 0.02 mm; E–I, 0.01 mm.