Chaetocladius berythensis, Moubayed & Langton, 2019

Moubayed, Joel & Langton, Peter H, 2019, CHAETOCLADIUS BERYTHENSIS SP. N., C. CALLAUENSIS SP. N., C. GUARDIOLEI SP. N. AND C. PARERAI SP. N., FOUR RELICT SPECIES INHABITING GLACIAL SPRINGS AND STREAMS IN EASTERN PYRENEES AND LEBANON (DIPTERA: CHIRONOMIDAE) Abstract, CHIRONOMUS Journal of Chironomidae Research 32 (32), pp. 42-59 : 43-44

Chaetocladius berythensis sp. n.

http://zoobank.org/ 12387DA9-9A16-45B7-8E4E-06DAA726D9A2

Material examined. Holotype. 1 male adult, Lebanon, Mount Sannine, glacial springs and small waterfalls located in the upper stream of the Beirut River , 33° 95’ 00’’ N, 35° 88’ 00’’ E, altitude 1800- 2000 m a.s.l., 05.VIII.2005, leg. J. Moubayed. Water calcareous, conductivity about 320 µS/cm; temperature 8-10 °C during summer, about 4-6 °C in winter and spring.

Paratype Lebanon. 1 male adult, leg. J. Moubayed-Breil. Same locality and date as for holotype .

Holotype (male adult, mounted on 1 slide) is deposited in the collections of the National Museum of Ireland, Kildare Street , Dublin 2, Ireland . Paratype is deposited in the collection of the senior author.

Etymology. The new species is named ‘ berythensis ’ after the name in Greek ‘ Berythus ’, which has given the name to the river Beirut.

Diagnostic characters

Based on the unusual shape of both virga and inferior volsella C. berythensis sp. n. keys to the laminatus -group as emended in Moubayed-Breil (2017). However, the new species can be separated from other related Chaetocladius species by the following combination of characters. Clypeus broadly cup-shaped with semi-circular median lobe distally, with 14 setae in 4 rows; palpomere 3 with 5 sensilla clavata and 11-12 short and truncate atypical sensilla coeloconica. Lobes of antepronotum widely gaping and parallel-sided medially; humeral pit ellipsoid without contrasting spots. Tergite IX with a truncate hump medially, clearly seen in lateral view; anal point triangular and sharply pointed. Virga consists of 3 separate parts including a median part (bearing 4 small equal spines) and 2 lateral symmetrically elongated parts (each with 1 orally directed claw medially). Gonocoxite rounded apically; inferior volsella large marsupial pouch-like lobe, bearing a contrasting protuberance proximally. Gonostylus massive, nearly rectangular, markedly projecting posteriorly at a rounded bare and hyaline apex; anterior margin sinuous, bearing 6-7 long setae; both dorsal and ventral median area with a distinct curved row of short spines reaching the base of megaseta. Crista dorsalis moderately to well-developed occupying about the length of the gonostylus, clearly visible in dorsal, ventral and lateral view; consisting of a series of smooth lobes which are lower proximally and terminates in a larger tooth located close to the megaseta.

Description

Male adult

(n = 2 male; Figs 1 A-N, 2A-C; associated material unknown)

Large. Total length 4.00- 4.10 mm. Wing length 2.35-2.40 mm, TL/WL = 1.70. General colouration contrasting brown to blackish. Head dark brown; antennae pale brown; thorax contrasting brown to dark brown, mesonotal stripes blackish; wing pale; legs brown to dark brown; tergites I-VII brownish, tergite VIII and anal segment dark brown.

Head. Eyes bare between ommatidia, hairs absent on inner lateral eye margin, outer posterior margin with a few short setae. 12 temporals including 7 inner (uniserial), 3 outer verticals and 2 postorbitals. Coronal area ( Fig. 1A ) with a distinct median tubercle. Palp 5-segmented, first and second segments are fused and unequal, segments 3 and 4 subequal; length (µm) of palpomeres: 18, 45, 145, 147, 235; palpomere 3 ( Figs 1 B-C) with 5 sensilla clavata and 11-12 unusually short and truncate atypical sensilla coeloconica. Clypeus ( Fig. 1D ) about 115 µm maximum height and 140 maximum width, broadly cup-shaped with median semi-circular lobe distally, with 14 setae in 4 rows. Antenna 1100-1130 µm long, 13-segmented; ultimate flagellomere 675 µm long, distinctly clubbed distally and bearing a dense brush of curved sensilla chaetica apically, pre-apical seta absent; antennal groove beginning on segments 3-4 and reaching ultimate flagellomere; AR 1.80. Thorax. Lobes of antepronotum ( Fig. 1E ), distinctly gaping and moderately thick medially, ventral part with 6 lateral antepronotals placed near the lower margin; humeral pit ( Fig. 1F ) ovoid and lacking contrasting spots; 23 short acrostichals located about 110 µm from antepronotum; dorsocentrals 14 in 1-2 rows; prealars 5 in 1 row; humeral pit ovoid to semi-circular, contrasting whitish to brown and lacking spots. Wing. Brachiolum with 1 seta; membrane densely covered with coarse punctuation; number of setae on veins: R, 0; R 1, 17; R 2+3, 1; remaining veins bare; squama with 14-15 setae in 1 row. Legs. Tarsomeres ta 4 of PI and PII equal in length (185 µm) as well for ta 5 of PI and PIII (140 µm); tibial spur of PI spiniform. Length (µm) of tibial spurs of: PI, 65; PII, 35 and 25; PIII, 70 and 30; longest seta of tibial comb 50 µm long. A few sensilla chaetica present (proximally and distally) on tibiae and tarsomeres ta 1 -ta 5 of PI-PIII. Length (µm) and proportions of prothoracic (PI), mesothoracic (PII) and metathoracic (PIII) legs as in Table 1 .

Hypopygium in dorsal view ( Fig. 1I ), ventral view with tergite IX and anal point omitted as in Fig. 1J . Tergite IX broadly semi-circular, with a distinct dorsal truncate hump medially which is visible when tergite IX is viewed laterally ( Figs 1 G-H), dorsal setae ( Figs 1I , 2A ) include 15 located on the antero-median part and 18-20 postero-medially close to the posterior margin (9-10, in 2 curved rows placed on each side of the base of anal point). Anal point ( Figs 1 G-H, 1I, 2A) 55-60 µm long, 35- 40 µm maximum width at base, triangular, sharply pointed apically and markedly wider at base, with bare and hyaline apex; 8-9 setae present both dorsally and laterally on anal point base. Latero-sternite IX with 10-11 setae inserted laterally (5-6 on each side). Sternapodeme and phallapodeme Fig. 1J , phallapodeme sickle-shaped anteriorly. Virga ( Fig. 1I ) consists of 3 separate parts which include: a median part with 4 small sub-equal teeth, 2 lateral parts which are elongated and bear 1 median claw-like projection orally directed. Gonocoxite ( Figs 1 I-J, 1L) 160 µm long and 125 µm maximum width, rounded apically, ventral margin slightly swollen basally, with 9 stout setae; inferior volsella in dorsal ( Figs 1I, K ) and lateral view ( Fig. 1L ) with a wide marsupial pouch-like lobe, and apical contrasting protuberance located proximally. Gonostylus ( Figs 1M , dorsal; 1N, lateral; 2B, ventral) 110 µm long and 65-70 µm maximum width, massively rectangular, markedly projecting posteriorly at a rounded bare and hyaline apex; anterior margin sinuous, bearing 6-7 long setae; dorsal and ventral median area with a distinct curved row of short spines reaching the base of the megaseta. Crista dorsalis moderately developed occupying nearly the length of the gonostylus, clearly visible in dorsal, ventral and lateral view, of a series of smooth lobes, which are lower proximally and ending with a larger distal tooth located close to the megaseta.

Figures

Figure 1. Male adult of Chaetocladius berythensis sp. n. A) head, frontal area (right side) with temporal setae; B) palpomere 3 with sensilla clavata and sensilla coeloconica; C) details of sensilla coeloconica; D) clypeus; E) lobes of antepronotum; F) humeral pit; G-H) two aspects of anal point and tergite IX in lateral view; I) hypopygium, dorsal; J) hypopygium, ventral; K) right inferior volsella; L) gonocoxite and inferior volsella, lateral; M) gonostylus, dorsal; N) gonostylus, lateral.

Figure 2. Male adult of Chaetocladius spp. C. berythensis sp. n.: A) anal point, dorsal; B) gonostylus, ventral; C) gonostylus, lateral. C. callauensis sp. n.: D) palpomere 3; E) clypeus; F) lobes of antepronotum; G) humeral pit.