Ripersiella illicians Schneider & LaPolla, 2022

Schneider, Scott A. & LaPolla, John S., 2022, A Neotropical complex of Ripersiella species (Hemiptera, Coccomorpha, Rhizoecidae) collected from the nests of Acropyga ants (Hymenoptera, Formicidae), ZooKeys 1123, pp. 1-30 : 1

Ripersiella illicians Schneider & LaPolla sp. nov.

Figures 5 , 6

Material examined.

Holotype. Peru • 1 adult ♀; Madre de Dios, Manu National Park, Cocha Cashu Biological Station , near trail marker 27:1150; -11.8833, -71.4000; 10.vi.2019; JS LaPolla, SA Schneider leg.; upland forest, from large nest of Acropyga goeldii (group) at base of tree; USNM (nest PER25-01: prep S0426E) . Paratypes. Peru • 3 adult ♀♀; same data as holotype; USNM (nest PER25-01: preps S0426B,D,F) • 1 adult ♀; same data as holotype; UNMSM (nest PER25-01: prep S0426C) • 1 adult ♀; same data as holotype; UNAB (nest PER25-01: prep S0426G) • 1 adult ♀; same data as holotype; UKMNH (nest PER25-01: prep S0426A) .

Description.

Adult female (N = 7). In life, body bright white to cream colored and visibly coated in powdery white wax.

General. Mounted on microscope slide, body broadly oval and membranous, 0.70-0.83 (0.78) mm long, widest at metathorax and abdominal segments I-II, 0.46-0.61 (0.55) mm wide. Abdomen rounded and gently tapering toward posterior apex; abdominal segment VIII 148-196 (196) μm wide at base. Anal lobes poorly developed with several flagellate setae on dorsum, 57-60 μm long. Body setae flagellate, 15-27 μm on head, 17-33 μm on thorax, 15-40 μm on abdominal segments. Trilocular pores abundant and distributed among body setae; multilocular disc pores absent; bitubular cerores absent; oral collar tubular ducts absent. Microtrichia apparently present only on dorsum of segments VI-VIII; rounded dermal micro-bumps present in intersegmental areas and surroundings of appendages. Internal genital organ sclerotized in some specimens of type series. Eyes absent.

Venter. Cephalic plate present. Labium with 3 segments; 82 μm long and 41 μm at widest point. Antennae geniculate, 6-segmented, closely situated near midline on ventral submargin of head; overall length 130-151 (151) μm; length of segment I: 30-37 (37) μm; segment II: 14-18 (18) μm; segment III: 17-20 (20) μm; segment IV: 14-19 (19) μm; segment V: 13-17 (17) μm; segment VI: 39-40 (40) μm; apical segment with 4 falcate stout sensory setate; a few flagellate setae present on each antennal segment, 19-30 μm long. Legs well developed; overall length of hind leg 274-290 (288) μm; length of hind coxa 43-44 (44) μm; length of hind trochanter + femur 102-108 (106) μm; length of hind tibia + tarsus 102-110 (110) μm; length of hind claw 26-31 (28) μm; each claw with stout setose digitule 1-2 μm long; flagellate setae present on each segment approximately 23 μm long. Single conical circulus present between abdominal segments III and IV, 22 μm in diameter; inner margin of orifice crenulated or with rugose projections.

Dorsum. Anal ring situated on dorsal surface separated from posterior body margin by approximately one-half diameter of ring, 59-61 μm in diameter; with oval cells lacking spicules; bearing 3 pairs of setae about 50 μm long. Posterior pair of ostioles present, diameter of orifice measured along longitudinal axis approximately 39 μm; anterior pair of ostioles absent.

Informal synonyms.

Specimens of R. illicians have been previously referred to in the literature as " Ripersiella undescribed (i)" ( Schneider et al. 2022).

Etymology.

The species epithet is an adjective formed from illicium, meaning attraction or enticement, and its use alludes to the apparent tendency of Acropyga colonies to gain rhizoecid partners through horizontal acquisitions. Such colonies have been figuratively attracted away from their primary associates in Xenococcidae .

Diagnosis.

Ripersiella illicians sp. nov. is similar to R. colombiensis as both species have a subcircular body shape, bearing one circulus, and both are lacking multilocular disc pores and an anterior pair of dorsal ostioles. However, R. illicians can be distinguished from R. colombiensis as follows (character states for R. colombiensis are given in parentheses): having 6-segmented antennae (5-segmented antennae); having comparatively long body setae, ranging from 15-40 μm (comparatively short, ranging from 15-25 μm); and having anal lobe setae that are distinctly longer than body setae, 57-60 μm (similar in length to body setae, 18-28 μm).

Comments.

Ripersiella illicians was discovered from a large nest of Acropyga goeldii (group). Root mealybugs were abundant in the nest, and wax could be seen on their body using a hand lens. Their direct association was confirmed through observation of the colony using a nest-box, as described by Schneider et al. (2022). After specimens were collected into a nest-box, worker ants gathered trophobionts into a protective cluster and were actively engaged in attending to them.

Figures

Figure 5. Ripersiella illicians Schneider & LaPolla sp. nov. Adult female, full body view, illustrated from holotype by T. Litwak (USDA ARS SEL), with edits by SAS.

Figure 6. Ripersiella illicians Schneider & LaPolla sp. nov. Scanning electron micrograph (SEM) by J. Mowery (USDA ARS SEL). Dorsal anterior view of adult female head and thorax, showing the absence of anterior ostioles and the presence of curled wax deposits and domed dermal micro-bumps in intersegmental areas.