Neoleptophlebia adoptiva ( McDunnough, 1929: 61 )

Burian, Steven K., 2024, Nymphs of the Northeastern Nearctic Species of Neoleptophlebia Kluge, 1997 and Paraleptophlebia Lestage, 1917 (Ephemeroptera: Leptophlebiidae), Zootaxa 5521 (1), pp. 1-65 : 8-9

Neoleptophlebia adoptiva ( McDunnough, 1929: 61)

Leptophlebia adoptiva McDunnough, 1929 (original description)

Paraleptophlebia adoptiva ( McDunnough, 1929) (combination)

Description of Nymph: Ide 1930: 209; Gordon 1933: 123; Leonard & Leonard 1962: 73

Nymphs of N. adoptiva are relatively large and conspicuous compared to those of the other species of Neoleptophlebia in the study region. Among the northeastern species of Neoleptophlebia , nymphs of N. adoptiva can be recognized by the combination of having sharp posterolateral projections only on abdominal segment IX ( Fig. 4a ); the base of mandibular incisors of the left mandible not extended above its anterior margin ( Fig. 5b ) and incisors of the left mandible not strongly curved inward; and the large, somewhat rectangular, pale spot anterior to the median ocellus on the frons of the head capsule ( Fig. 6 ). These characters seem consistent on nymphs from mid-development to the final instar. The posterolateral projections on abdominal segment IX are clear throughout development, but on some late instar nymphs the corners of the segment VIII tergite can appear to be somewhat acute giving the false impression that a posterolateral projection is present. Thus, simply having an acute tip to the corner of tergite VIII is not to be interpreted as a posterolateral projection. Correct interpretation of the mandibular incisor character requires locating the anterior margin of the mandible between the molar surface and the incisors. If a line drawn across the anterior margin would pass through or very close to the bases of the incisors, then the incisors are not considered to extend beyond the anterior margin. Although the incisor character can be observed on both mandibles ( Figs. 5a,b ), it is best observed on the left mandible for comparative purposes with other species of this genus. Moreover, because the incisors of the left mandible are not extended beyond the anterior margin, they also do not distinctly curve inward. Mandibles can be observed without slide mounting by carefully using a pin-probe to severe the outer articulation point on each mandible, thus allowing them to be rotated outward for viewing.

Neoleptophlebia adoptiva is widely distributed with records in 12** of the 14 states and provinces ( Table 2). Only RI and PE** currently lack records. The presence of N. adoptiva in NL-I indicates that dispersal to offshore islands is possible and the lack of records from other areas is likely the result of sampling effort. The widespread distribution of N. adoptiva is the result of its ability to make use of suitable microhabitats in both small streams and larger rivers. Thus, because N. adoptiva occurs in such a wide range of stream habitats it is likely one of the most secure species in this genus across its range with regards to changes in regional hydrology predicted to occur because of climate change ( Hicke et al. 2022).

[**—Records of N. adoptiva for PE, not reviewed here, were discovered after this study was completed and reported as Paraleptophlebia sp. in: Eedy, R.I., & D.J. Giberson (2007) Macroinvertebrate distribution in a reach of a north temperate eastern Canadian river: Relative importance of detritus, substrate and flow. Fundamental and Applied Limnology (Archiv für Hydrobiologie) 169: 101-114.]

Figures

FIGS. 1–4: gills and abdominal tergites VIII–X of Neoleptophlebia and Paraleptophlebia nymphs. 1. N. adoptiva gill 4, 2. P. praepedita gill 4, 3a. N. assimilis tergites VIII–X, 3b P. praepedita tergites VIII–X, 3c. P. volitans tergites VIII–X, 3d. P. moerens tergites VIII–X, 4a. N. adoptiva tergites VIII–X, 4b. P. guttata tergites VIII–X.

FIGS. 5–8: mouthparts and dorsal view of the head of Neoleptophlebia nymphs. 5a. right mandible (ventral view) of N.adoptiva, 5b Left mandible (ventral view) of N. adoptiva 6. dorsal view of head of N. adoptiva, 7a. right mandible (ventral view) of N. mollis, 7b-c. left mandible (ventral view) of two N. mollis specimens showing differences in position of outer incisors, 8. dorsal view of head of N. mollis.