Simulium (Hearlea) johnsoni Vargas & Díaz Nájera

Coscarón, S., Esquivel, D. R. Miranda, Moulton, J. K., Arias, C. L. Coscarón- & Bernal, S. Ibañez, 2004, Simulium (Hearlea) Vargas, Martínez Palacios, & Díaz Nájera (Diptera: Simuliidae): Taxonomic revision and cladistic analysis, Zootaxa 396, pp. 1-52 : 28

Simulium (Hearlea) johnsoni Vargas & Díaz Nájera

Figs. 6H, I .

Simulium (Hearlea) johnsoni Vargas & Díaz Nájera, 1957: 203–205 , Figs. 152–160; Díaz Nájera & Vulcano, 1962: 99–100, Figs. 72–75

(Diagnosis of adults based on description from Vargas & Díaz Nájera 1957, and that of larva from Díaz Nájera & Vulcano 1962)

Female: Wing length, 3.1 mm. General coloration blackish. Scutum black with 2 submedian silvery vittae not adjoining 1+1 anterior subtriangular silvery spots. Anterior portion of cibarium with thickened anterior margin, medially concave. Sc with 4–6 hairs. Genitalia similar to those of S. larvispinosum .

Male: Wing length, 3.1 mm. Coloration blackish, scutum velvety black whitish on anterior border. Abdominal tergites blackish. Genitalia as in S. larvispinosum .

Pupa: Length: basal, 3.1 mm; dorsal, 2.9 mm. Cocoon slipper shaped. Gill membranous, with general shape similar to that of S. larvispinosum but secondary branches shorter and ventral branch more strongly curved; accessory branches accuminate, with well sclerotized spine­like apices ( Figs. 6H–I ). Frontoclypeus smooth. Anterodorsum of thorax with abundant small platelets medially and few granules laterally. Posterodorsum of thorax with sparse, small, accuminate granules.

Larva: Length, 8.5 mm. Coloration gray. Cephalic apotome uniformly pigmented, with small thin darkened area mediobasally. Labral fan with 54–56 primary rays. Ratio of antennal articles = 1:1.4:1.0 (proximal: medial: distal). Mandible with preapical teeth robust, internal teeth in two rows of 5; 2 large marginal teeth and 3; lateral mandibular process long and curved. Hypostoma with anterior margin straight and 10–12 lateral setae per side; ratio of hypostoma/hypostomal bridge = 0.7. Postgenal cleft dome shaped; abdominal segment VIII without sublateral papillae. Posterior circlet with 242 rows of 26–30 hooks. Anal sclerite with ventral struts encircling posterior circlet; 2+2 dorsolateral accesory plates with subconical processes, and 1+1 wide lateroventral plates bearing 4–5 short lateral processes. Segment VIII without ventrolateral papillae. Rectal papillae trilobed, with 7 lobules per lobe (21 total), the dorsalmost ones largest.

Material examined: México: Veracruz, Cascada de Teocelo , 2 pupae (on slide), May 1946, Parra ( MLP) .

Distribution: México, Oaxaca and Veracruz.

Discussion: Simulium gorirossiae is very similar to S. johnsoni but the pupa gill of the former has the anterodorsal lobe of the median branch thinner and more accuminate distally (actually with terminal spine) and the ventral branch is only slightly curved medially. The larva of S. johnsoni differs from that of S. gorirossiae by having longer projections on the accessory ventrolateral plate and ventrolateral papillae on segment VIII. Simulium temascalense has a very similar pupal gill to S. gorirossiae but its large anterodorsal lobe of the median branch is spinulate apically, and its larva has ventrolateral papillae on segment VIII and shorter lateral projections of the accessory ventrolateral plates. The pupal gill of S. larvispinosum has larger secondary branches and a more curved ventral branch, and its larva has 1+1 dorsolateral accessory rectangular plates anterior to the rectal papillae.

Figures

FIGURE 6. Pupa and respiratory organ. A–E. S. (H.) larvispinosum; A. lateral view, B. dorsal view, C. lateroexternal view; D. laterointernal view; E. dorsolateral view, F–G. S. (H.) gorirossiae F. dorsal view. G. lateroventral view, H–I S. (H.) johnsoni, H. dorsal view, I. latero external view. J–K. S. (H.) menchacai, K. dorsal view. (A, J, K and C, B, D, I same scale respectively).