Pseudosinella hahoteana Soto-Adames, Bernard & Wynne

Bernard, Ernest C., Soto-Adames, Felipe N. & Wynne, J. Judson, 2015, Collembola of Rapa Nui (Easter Island) with descriptions of five endemic cave-restricted species, Zootaxa 3949 (2), pp. 239-267 : 257-259

Pseudosinella hahoteana Soto-Adames, Bernard & Wynne , n. sp.

Figures 7 C, 12

Material examined. CHILE, Rapa Nui, Maunga Hiva Hiva region, holotype (juvenile), Cave Q15-074, direct search in fern-moss garden, sympatric with Lepidocyrtus olena , 13 July 2009, J. Wynne, coll.

Description. Size to 1.1 mm. Body uniformly light blue with darker streaking on Abd. IV ( Fig. 7 C). Scales present on head, body and ventral face of furcula.

Apical bulb of Ant. IV large, unlobed ( Fig. 12 B); subapical sense organ acuminate, as large as guard sensillum; chaetotaxy dominated by thin-walled, apically blunt sensilla instead of normal acuminate, thick walled setae. Sense organ of Ant. III with 2 normal rods and at least 6 additional short, blunt sensilla. Eye patch with 4 eyes ( Fig. 12 A). Dorsal head macrosetae ( Fig. 12 A) with A0, A2, A3, Pa5 present in addition to 6+ 6 in series An. All head microsetae acuminate, weakly ciliate. Prelabral setae weakly ciliate, labral setae smooth. Distal margin of labrum smooth. Outer maxillary lobe with basal and distal setae smooth and subequal; sublobal plate with 4 setae. Lateral appendage of labial papilla E bent anteriorly and not reaching tip of papilla. Proximal labial setae smooth. Labial triangle setae ( Fig. 12 C) as M1rE1L1L2A1-5: A1 serrate, other elements in series A smooth; r short, smooth and conic, all other posterior setae coarsely ciliate. All postlabial setae ciliate, modified setae absent.

Dorsal macrosetae formula 00/0222+0+6. Mesothoracic hood not developed; macrosetae absent; polychaetosis absent. Metathorax chaetotaxy complete (cf. Szeptycki 1979); macrosetae absent. On Abd. I seta a6 absent, all posterior setae present. Second abdominal segment ( Fig. 12 D) with macrosetae m3 and m5 present; supplementary setae associated with bothriotricha m2 and a5 smooth or weakly ciliate; all other microsetae smooth; setae a2p, m 4i and p5p absent; seta a3 anterior to and reaching sensillum as. Supplementary setae on Abd. III weakly ciliate ( Fig. 12 E), all other microsetae smooth; seta a3 anterior and reaching sensillum as; as less than half as long as m3; sensillum d2 absent; seta a7 anterior to im and em, reaching am6. Fourth abdominal segment ( Fig. 12 F) with 2 inner (B5, B6) and 6 lateral macrosetae (T6, D2, E1, E2, E3, F1), E1 smaller than other macrosetae; 1‒2 additional latero-posterior macrosetae of uncertain homology present; all supplementary setae ciliate or weakly ciliate, setae s and a absent; seta T3 clearly anterior and not reaching D1p; microseta F 2 in row with D2 and E2; posterior setae absent.

Trochanteral organ with 6 setae, 5 arranged in 'V' formation and 1 detached. Metatibiotarsi without outstanding posterior setae. Tenent hair acuminate. Unguis ( Fig. 12 G) with 3 inner teeth inserted at 34%, 46%, 56% of inner edge; distal paired tooth minute; lateral and outer teeth ending near basal third of claw. Unguiculus lanceolate on all legs, posterior lamella with 2‒3 small teeth.

On ventral tube distal row of anterior face with 2 macrosetae. Lateral flaps and posterior face not seen. Dens tubercle absent. Mucro ( Fig. 12 H) with apical tooth slightly longer than subapical, basal spine smooth.

Remarks. Pseudosinella hahoteana n. sp. is the only member of the genus with four eyes, apical bulb on Ant. IV and acuminate tenent hair. The new species is most similar to the East Asian P. tridentifera Rusek, 1971 , from which it differs by having an apical bulb on Ant. IV, labial seta r smooth and conic, macroseta m3 on Abd. II, macroseta B6 on Abd. IV and inner unpaired ungual tooth inserted distally (42% in P. tridentifera vs. 56% in P. hahoteana ). Two other members of the genus, P. canariensis Gama, 1974 and P. fonsa Christiansen & Bellinger, 1992 , have four eyes and only two inner macrosetae on the fourth abdominal segment, but both species carry seta a2p on Abd. II and lack the apical bulb on Ant. IV.

Etymology. This animal was named using a combination of two Rapanui terms that when translated to English mean “mouth of the cave.” Hahote is Rapanui for “mouth” and ana means “cave.” Currently, this species is known only from fern-moss gardens within the cave entrance.

Figures

FIGURE 7. Lateral views of whole specimens. A) Coecobrya kennethi Jordana & Baquero. B) Coecobrya aitorererere n. sp. C) Pseudosinella hahoteana n. sp. D) Seira manukio n. sp. E) Lepidocyrtus olena Christiansen & Bellinger. All scales 200 Μm. Images 7 A, C and D were previously published in BioScience, 64, 711 ‒ 718 (2014).

FIGURE 12. Pseudosinella hahoteana n. sp. A) Dorsal chaetotaxy of head. B) Fourth antennal segment, apical papilla. C) Labial triangle chaetotaxy. D) Second abdominal segment chaetotaxy. E) Third abdominal segment chaetotaxy. F) Fourth abdominal segment chaetotaxy. G) Metathoracic foot complex. H) Mucro and distal section of dens showing transition from crenulate to smooth surface. Open and closed circles represent macro- and microsetae, respectively.