Neochavesia podexuta Schneider & LaPolla, 2023

LaPolla, John S. & Schneider, Scott A., 2023, Trophobiosis between a new species of Acropyga (Hymenoptera, Formicidae) and new Neochavesia (Hemiptera, Xenococcidae) from Peru, and establishment of the Acropyga smithii species-group, ZooKeys 1154, pp. 1-16 : 1

Neochavesia podexuta Schneider & LaPolla sp. nov.

Fig. 14

Description.

Adult female (N = 7). In life, body bright white to cream colored and free of wax. Mounted on microscope slide, body elongate-pyriform, 1.35-1.58 mm long, 0.55-0.73 mm wide at widest point; head and thorax dilated with widest point at metathorax and abdominal segment I. Abdomen constricted after segment III; segments IV-VII gently tapering in width posteriorly with another constriction between segments VII and VIII. Dorsal posterior half of abdominal segment VIII sclerotized; anterior half membranous and free of setae, forming a distinctive bald patch; width of segment 145 μm wide. Anal lobes well developed and separated from abdominal segment VIII on venter and margins of dorsum by an intersegmental line. Anal lobes diverging with a roughly U-shaped notch between them, each rounded at posterior end. Dorsum of each anal lobe with numerous long flagellate setae, longest about 135 μm, situated at posterior end, with those at anterior end about 35 μm; ventral surface with similar setae 32-90 μm long. Anal ring roughly triangular, without cells or setae, 65 μm wide; anterior end lying along the intersegmental division that separates the anal lobes from abdominal segment VIII, posterior edge removed from the apical notch between lobes by about 1X length of anal ring. Long antennae widely spaced on dorsal head margin; basal segment set into a notch on the head and articulating; each with four segments, 652-663 μm in overall length; average lengths of segments (base to apex) 56 μm, 297 μm, 95 μm, 215 μm; the apical segment appearing partially divided, indicating an obsolete fifth segment; few flagellate setae on basal antennal segment, numerous such setae on all other segments, 30-55 μm long. Legs well developed; average length of metatrochanter + femur 212 μm long; metatibia + tarsus 150 μm long; tarsus swollen basally and abruptly tapering; with metaclaw 70-80 μm long, longer than tarsus. Ratio of length of metatibia to tarsus, 1.60; leg segments with multiple stout flagellate setae. Labium 3-segmented, 147 μm long, longer than clypeolabral shield, 70 μm wide; basal segment with three pairs of setae; eight pairs of setae on terminal segment. One round circulus present, situated towards center of abdominal segment II, 16 μm in diameter, conical and projecting from derm, cup-shaped internally. Spiracles normal, 35 μm in diameter at widest point.

Dorsal surface of head and thorax crowded with slender flagellate setae, about 17 μm long, few approaching 45 μm at posterior end of metathorax, most with small setal collars, longer setae with slightly wider collars; abdominal segments with similar setae but less densely crowded after segment I; on each segment, setae at anterior end shorter and finer than posterior setae, ranging from 19-75 μm on segment I, upwards of 95 μm on segments II-VI, shorter setae 25-40 μm on VII-VIII, longest setae on anal lobes, from 32-135 μm. Venter with similar setation; less densely crowded on head and with greater variation in setal lengths, 15-40 μm; thoracic margin to submargin similar to dorsum; thoracic submedian similar to ventral head; abdominal segments I-IV similar to dorsum, segments V-VIII with shorter setae, anal lobes with numerous long setae but generally shorter than those found on dorsum. Pores and ducts absent.

Material examined.

Holotype: Peru • 1 adult female; Madre de Dios, Las Cruces, Manu Paradise Lodge , from Acropyga manuense nest behind lodge, in soil around small rotting branches; 13.055°S, 71.544°W; 31.v.2019; J.S. LaPolla and S.A. Schneider leg.; UNMSM (nest ID PER01-02; prep S0401E) . Paratypes: Peru • 6 adult females; same data as holotype; USNM (nest ID PER01-01; preps S0400A,B,C,D,E,F) • 1 immature female; same data as holotype; USNM (nest ID PER01-02; prep S0401A) .

Informal synonyms.

This species was previously referred to as " Neochavesia undescribed" in Schneider et al. (2022).

Etymology.

The epithet is a noun in apposition, referring to the distinctive bald patch located just anterior to the anal opening. The Latin ' podex ', meaning fundament/anus, was combined with ' exutus ', meaning bared or stripped.

Remarks.

Neochavesia podexuta bears a distinctive bald patch on the dorsal anterior surface of abdominal segment VIII. On slide-mounted specimens, it often appears as though this segment, including the anal lobes, has become detached from the rest of the body although it is still intact. In life, species of Neochavesia hold their abdomen in a curled position over their dorsum, resembling the tail of a scorpion; this bald membranous patch is located where the cuticle would curve inward. Adult females of Neochavesia podexuta are similar to N. cephalonodus , N. eversi , N. iwokramae , and N. lapollai in possessing antennae that articulate at the basal segment with a sclerotized prominence (forming a socket) on the head. They also lack a pair of setae on the middle labial segment, a characteristic shared among these species as well. The new species is most akin to N. eversi ; the former can be distinguished from the latter by the bald patch on VIII described above and by their longer antennae. In N. podexuta , the body is about 2.0-2.5 times longer than the antennae with the second segment almost 300 μm long; whereas in N. eversi , the body is roughly 3.5 times the length of the antennae with the second segment only about 150 μm long.

Direct association between A. manuense and N. podexuta was confirmed by collecting ants and root mealybugs into a nest-box and observing interactions ( Schneider et al. 2022). Ants gathered root mealybugs into protective clusters within the nest-box and were observed actively tending them. These observations were made over a 48-hour period in field-based laboratory conditions.

Figures

Figure 14. Neochavesia podexuta sp. nov. Adult female, full body view, illustrated from the holotype and paratypes. Illustration by Taina Litwak (USDA, ARS, Systematic Entomology Laboratory) with edits by SAS.