Colobaea deemingi, Bratt & Knutson & Murphy & Daniels, 2020

Bratt, Albertus D., Knutson, Lloyd V., Murphy, William L. & Daniels, Anthony A., 2020, Biology, immature stages, and systematics of snail-killing flies of the genus Colobaea (Diptera: Sciomyzidae), with overviews of aspects of the tribe Sciomyzini, Zootaxa 4840 (1), pp. 1-64 : 40-41

Colobaea deemingi n.sp.

Egg (similar to that in Fig. 5 ) (based on 10 specimens from Dezful , Iran). Length 0.40–0.50 mm; greatest width 0.14–0.18 mm. Robust, spindle shaped; anterior and posterior ends smoothly rounded; ventral surface more convex than dorsal surface in lateral aspect. Chorion finely punctate, sculptured into polygonal cells; longitudinal ridges of cells stronger ventrally, imparting noticeable striated appearance; dorsal surface with reticulate appearance .

First-instar larva (based on 10 specimens from Dezful , Iran). Length 0.50–0.70 mm; greatest width 0.07–0.14 mm. Post-oral spinules very long, slender, recurved, lightly pigmented. Cephalopharyngeal skeleton light brown, 0.09–0.10 mm long. Indentation index 82–88. Mouthhooks long, slender; pharyngeal sclerites strongly sclerotized .

Posterior end with three pairs of large marginal lobes plus lateral protuberances. Large, darkly pigmented spinules below spiracular plates ( Fig. 29 ). Spiracular tubes 0.017 mm long, slender. Float hairs long, slender. Peri-anal pad large, protrudent, subovate, with apices attenuated.

Second-instar larva (based on four specimens from Dezful, Iran). Length 1.6–1.8 mm; greatest width 0.2–0.3 mm. Body form slender, spindle shaped. Post-oral spinules numerous, large, sharp; cephalopharyngeal skeleton ( Fig. 12 ) dark brown; 0.20 mm long. Indentation index 76–80. Pharyngeal sclerites short; dorsal and ventral cornua with incomplete windows; mouthhooks long, with small, recurved hook part; ventral arch small, straplike, with 18–20 small, slender teeth. Anterior spiracles small, with 12–15 marginal papillae.

Spinules present on lateral pads; segmental spinules sparse, lightly pigmented.

Posterior end with three pairs of large marginal lobes plus lateral protuberances. Mammillae present at bases of ventral lobes. Peritremes lightly pigmented, three spiracular slits in central, pigmented area; no hyaline float hairs ( Fig. 14 ).

Third-instar larva (based on 10 specimens from Dezful , Iran). Length 2.2–3.5 mm; greatest width 0.4–0.9 mm. Body form spindle shaped, lateral welts not apparent, posterior half of body not expanded, lateral pads visible. Anterior spiracles ( Fig. 33 ) with expanded apical part, 12–14 marginal papillae tightly enclosed by integument .

Cephalopharyngeal skeleton ( Fig. 43 ) dark brown, 0.34 mm long. Indentation index 80. Mouthhooks large, hook part directed ventrally. Ventral arch slender, with 18–20 teeth. Several rows of dark spinules by oral opening, lateral to mouthhooks. Dorsal cornu with small, complete window; ventral cornu with large, elongate window; apparent margins of cornua entire.

Spinules present on lateral pads; segments III and IV with ventral spinule patch, segment V with two-part patch, segments VI–XII with three-part patches. Segmental spinules small, lightly pigmented.

Posterior end ( Fig. 19 ) with four pairs of lobes; dorsal pair small, ventral and ventrolateral pairs large, conical; lateral protuberances large, less acute than lobes. Mammillae present at bases of ventral lobes. Peritremes, slit margins, and stigmatic scars lightly pigmented ( Fig. 30 ). Peri-anal pad with lateral margins attenuated into points.

Puparium ( Figs 45–46 ) (based on six specimens from Dezful, Iran). Length 4.1–5.0 mm; greatest width 1.0– 1.1 mm. Typically distorted to fit planorbiform snail host shell. Dorsal surface of segments II–IV dark, reddish brown if host shell is planorbiform or else all exposed surfaces darkly pigmented; other integument tan. Integument subshiny, finely punctate. Segmentation, secondary integumentary folds, and spinules obscure. Lateral pads and lateral longitudinal welts visible on segments IX–XI.

In dorsal aspect, dorsal cephalic cap flattened and expanded to occlude whorl of host shell; widest at posterior margin of segment V and then narrowed abruptly and continued with margins parallel to those of segment XI, which narrows to rounded end of posterior spiracular disc. Crescent shaped in lateral aspect, segments VI–IX depressed by inner whorl of host shell.

Anterior spiracles small, projecting dorsally from anterolateral angles of cephalic cap; papillae very small. Posterior spiracles large, protrudent from dome-shaped disc; marginal lobes small, pointed. Posterior spiracular disc not darkened. Peri-anal pad suboval, concolorous, not invaginated.

Figures

FIGURES 5–7. Eggs, lateral outline: 5, Colobaea pectoralis (Zetterstedt); 6, C. americana Steyskal; 7, C. bifasciella (Fallén). Measurement in mm.

FIGURES 28–30. Posterior spiracular plates: 28, Colobaea americana Steyskal, first-instar larva; 29, C. deemingi Knutson & Bratt, first-instar larva; 30, C. deemingi, third-instar larva. Abbreviations: FH, float hair; PGO, perispiracular gland opening. Measurement in mm.

FIGURES 9–12. Cephalopharyngeal skeletons: 9, Colobaea pectoralis (Zetterstedt), first-instar larva; 10, C. pectoralis, second-instar larva; 11, C. punctata (Lundbeck), second-instar larva; 12, C. deemingi Knutson & Bratt, second-instar larva.Abbreviations: DB, dorsal bridge; DC, dorsal cornu; HS, hypostomal sclerite; MH, mouthhook; PS, pharyngeal sclerite; VA, ventral arch; VC, ventral cornu. Measurement in mm.

FIGURES 13–14. Posterior spiracular plates of second-instar larvae: 13, Colobaea americana Steyskal; 14, C. deemingi Knutson & Bratt. Abbreviations: Pt, peritreme; SpS, spiracular slit; StS, stigmatic scar. Measurement in mm.

FIGURES 32–35. Anterior spiracles, third-instar larvae: 32, Colobaea pectoralis (Zetterstedt); 33, C. deemingi Knutson & Bratt; 34, C. punctata (Lundbeck); 35, C. bifasciella (Fallén). Abbreviations: PrS, prismatic spot; StS, stigmatic scar. Measurement in mm.

FIGURES 40–43. Cephalopharyngeal skeletons of third-instar larvae: 40, C. punctata, lateral view; 41, C. pectoralis, lateral view; 42, C. bifasciella (Fallén), lateral view; 43. C. deemingi Knutson & Bratt, lateral view. Abbreviations: AvP, anteroventral process of pharyngeal sclerite, DB, dorsal bridge, DC, dorsal cornu, DW, dorsal window, ES, epistomal sclerite, HS, hypostomal sclerite, LS, ligulate sclerite, MH, mouthhook, PB, parastomal bars, PS, pharyngeal sclerite, VA, ventral arch, VC, ventral cornu, VW, ventral window. Measurement in mm.

FIGURES 15–20. Posterior ends of third-instar larvae: 15, Colobaea americana Steyskal, caudal view; 16, C. bifasciella (Fallén), caudal view; 17, C. pectoralis (Zetterstedt), caudal view; 18, C. punctata (Lundbeck), caudal view; 19, C. deemingi Knutson & Bratt, caudal view; 20, C. punctata, lateral view.Abbreviations: DL, dorsal lobe, LP, lateral pad, M, mammillae, PaP, peri-anal pad, SpP, spiracular plate, SpT, spiracular tube, VL, ventral lobe, VlL, ventrolateral lobe. Measurement in mm.

FIGURES 44–48. Puparia, lateral and dorsal views: 44, Colobaea americana Steyskal, lateral view; 45, C. deemingi Knutson & Bratt, lateral view; 46, C. deemingi, dorsal view; 47, C. punctata (Lundbeck), lateral view; 48, C. punctata, dorsal view. Measurement in mm.