Massalongia nakamuratetsui Elsayed & Tokuda, 2020

Elsayed, Ayman Khamis, Skuhrava, Marcela, Ohta, Kazuki, Yoshida, Satoshi & Tokuda, Makoto, 2020, Revision of the birch-associated genus Massalongia (Diptera, Cecidomyiidae), with description of a new species from Japan and a taxonomic key to worldwide species, ZooKeys 958, pp. 1-27 : 1

Massalongia nakamuratetsui Elsayed & Tokuda sp. nov.

Description.

Head (Figs 4-9 ). Eyes separated on vertex by diameter of 0.0-1.25 facets. Frons with 3-9 setae (n = 9). Mouthparts: labrum with 8-10 setae (n = 9); hypopharynx with thick microtrichia on edges; labellum microtrichose, with 4-5 setae (n = 5); palpal segments consecutively longer. Antenna: scape and pedicel microtrichose and with few ventral setae on basal half; flagellomeres III-XII usually with few microtrichia concentrated on base of node; male flagellomere XII sometimes pointed apically.

Thorax (Figs 10 , 11 ). Wing 2.6-2.9 mm long in males (n = 6), 3.1-3.3 mm long in females (n = 3). Anepimeral setae 11-17 (n = 9).

Female abdomen (Figs 12 - 15 ). Tergites I-VII with few lateral setae. Ovipositor: stiff dorsal sclerite present along protrusible portion, posteriorly wider than anteriorly; protrusible portion ca. 1.3 as long as tergite VII; cerci elongated, with scattered setae lateroapically; hypoproct short.

Male abdomen. Tergite VIII without posterior row of setae. Terminalia (Figs 16-18 ): gonostylus with blunt denticles, ventrally with cluster of short setae near base; cerci with tapered and setose apex, basal part of cerci without setae; hypoproct bilobed, narrowed after midlength; aedeagus shorter than cerci and hypoproct, cylindrical in dorsoventral view, wide basally in lateral view.

Pupa (Figs 19-21 ). Antennal horns with short, acute, apical protuberances; 2 setose and 2 asetose lower facial papillae present; 1 asetose and 2 setose lateral facial papillae present on each side. Prothoracic spiracle, about 270 μm long, with trachea extending to tip. Abdominal terga I-VII each with 4 setose and 2 asetose dorsal papillae; terga VIII with 4 setose dorsal papillae. Abdominal terga II-VIII with 3-4 median rows of slightly wider and longer spinules than surrounding ones.

Mature larva (Figs 22-24 ). In life, orange. Spatula short and bilobed. Dorsal papillae without setae on thoracic segments, with setae on abdominal segments. Two asetose pleural papillae on thoracic segments; 2 setose and 1 asetose pleural papillae on abdominal segments. Terminal segment with 8 papillae: 4 corniform and 4 setose.

Etymology.

The species is named in honor of the late Japanese physician Dr. Tetsu Nakamura in recognition to his lifelong dedication to supporting poor people and his significant contributions to the development of Afghanistan. Dr. T. Nakamura was fatally shot by extremists on 4 December 2019 in Afghanistan, exactly on the date when we prepared the first draft of this paper and were considering what to name the species. In this way, we wish to immortalize his contributions to humanity.

Type material.

Holotype. 1♂ (ELKU): Reared from larvae in bottle-like cocoons collected under B. grossa by A. K. Elsayed on 15.xii.2018 from Mount Tara, Saga Prefecture, Japan on 15.xii.2018, emerged on 15.iii.2019. Paratypes. All reared from larvae in bottle-like cocoons collected under B. grossa by A. K. Elsayed at the type locality, as follows. 3 larvae: obtained from cocoons on 15.xii.2018; 1 pupal exuviae: emerged on 23.iii.2019; 2♂, 1♀, 2 pupal exuviae: emerged on 27.iii.2019; 2♂, 2♀: emerged on 30.iii.2019; 1♂: emerged on 4.iv.2019.

DNA accession numbers.

LC557490-LC557493.

Distribution.

Japan: Kyushu Island, Saga Prefecture.

Gall and life history.

Massalongia nakamuratetsui forms galls on the midveins of B. grossa (Fig. 1 ). One leaf can bear several galls and some galls become fused with larvae occupying separate chambers. Galls are 1.52-3.10 mm in diameter and 6.46-18.03 mm long. Galls collected at the end of August contained white first instars. Larvae develop to second and mature larvae by the end of September. In late October, the mature larvae leave the galls to overwinter in the ground, where they spin hyaline, bottle-shaped cocoons on leaf litter (Figs 2 , 3 ). The cocoon of M. nakamuratetsui is waterproof and does not allow water to reach the overwintering larva (Suppl. material 1: Video S1). Adults emerge between the end of March and the beginning of April.

Remarks.

Massalongia nakamuratetsui is most similar to M. papyriferae , sharing a bilobed sternal spatula, four setose and four coniform larval terminal papillae, gonostyli ending with blunt denticles and bilobed male hypoproct ( Gagné 1967, 1973). They can be separated as follows: anterior lobes of spatula are directed anteriorly in M. nakamuratetsui , but curved toward each other in M. papyriferae ; gonostylus is less curved distally in M. nakamuratetsui compared to M. papyriferae ; ovipositor has dorsal pigmentation along the protrusible portion in M. nakamuratetsui , but only on the distal two thirds in M. papyriferae .

Figures

Figures 4 - 11. Massalongia nakamuratetsui sp. nov. 4 head 5 ventral view of mouthparts 6 female antenna 7 male antenna 8 dorsal view of female flagellomere V. 9 dorsal view of male flagellomere V. 10 wing 11 tarsomere V and acromere. Scale bars: 50 µm.

Figures 12 - 13. Terminal part of female abdomen of Massalongia nakamuratetsui sp. nov. 12 dorso-lateral view 13 ventro-lateral view. Scale bars: 50 µm.

Figures 14 - 18. Massalongia nakamuratetsui sp. nov. 14 terminal part of female abdomen (arrow indicate the dorsal sclerite on the protrusible portion) 15 protrusible portion of ovipositor 16 male terminalia 17 ventral view of gonostylus 18 ventral view of male hypoproct. Scale bars: 50 µm.

Figures 19 - 21. Pupa of Massalongia nakamuratetsui sp. nov. 19 ventral view of head 20 prothoracic spiracle 21 dorsal view of terminal part of abdomen (arrows indicate dorsal spines). Scale bars: 50 µm.

Figures 22 - 24. Larva of Massalongia nakamuratetsui sp. nov. 22 spatula 23 ventral view of terminal abdominal segments 24 dorsal view of terminal abdominal segments. Scale bars: 50 µm.

Figures 1 - 3. Massalongia nakamuratetsui sp. nov. 1 leaf galls (red arrows) on B. grossa 2 overwintering larva in cocoon on leaf litter 3 bottle-shaped cocoon.