Anastrepha aphelocentema Stone, 1942

Rodriguez, Erick J., Steck, Gary J., Moore, Matthew R., Norrbom, Allen L., Diaz, Jessica, Somma, Louis A., Ruiz-Arce, Raul, Sutton, Bruce D., Nolazco, Norma, Muller, Alies & Branham, Marc A., 2022, Exceptional larval morphology of nine species of the Anastrepha mucronota species group (Diptera, Tephritidae), ZooKeys 1127, pp. 155-215 : 155

Anastrepha aphelocentema Stone, 1942

Figs 1-5 , 6-11 , 12-13

Material examined.

Mexico • 4 larvae; Veracruz, Xalapa, Papantla ; 20.3992°N, 97.3469°W; 72 m a.s.l.; Jul.1998; M. Aluja leg.; reared from fruit of Pouteria glomerata (Miq.) Radlk. ( Sapotaceae ); FSCA (AP20171024.07, AP20190827.04, AP20180726.01-AP20180726.02) .

Diagnosis.

Anastrepha aphelocentema runs to A. leptozona Hendel in the key of Steck et al. (1990), and to two species ( A. leptozona and A. serpentina ) in that of Carroll et al. (2004). It differs from all species within the Anastrepha mucronota group in having the posterior margins of the oral ridges and accessory plates finely serrate or entire. In addition, A. aphelocentema can be separated from A. curvicauda (Gerstaecker) by the position of the preoral organ (lateral vs. anterior to the mouthhook), and from A. curitis Stone in having a higher number of oral ridges (12-14 vs. 8-11). It can be also distinguished from most other species for which larvae have been described by the number of tubules of the prothoracic spiracle (24-27). This includes larvae of A. pallens Coquillett of the daciformis group (17-22 tubules), various species of the Anastrepha fraterculus group (9-22; see Rodriguez et al. 2021), A. grandis (Macquart) of the Anastrepha grandis group (31-37), A. leptozona of the Anastrepha leptozona group (15-21), two species of the pseudoparallela group ( A. limae Stone with 18-21, and A. consobrina (Loew) with 12-15), two species of the Anastrepha spatulata group ( A. pickeli Lima with 16-23, and A. interrupta Stone 10-13), two species of the Anastrepha serpentina group ( A. pulchra Stone with 18-23, and A. serpentina (Wiedemann) with 13-19), and two species of the Anastrepha striata group ( A. bistrigata Bezzi with 13-20, and A. striata Schiner with 11-18). The larva of Anastrepha sagittata Stone (dentata group), reared from seeds of the related species Pouteria campechiana (Kunth) Baehni, was described with limited data ( Baker et al. 1944) but can be morphologically separated from A. aphelocentema by the longer and narrower posterior spiracle openings.

Description.

Habitus. Third instar elongate, cylindrical, tapered anteriorly and truncate posteriorly; color creamy; amphipneustic. Length 11.00-11.77 mm and width 2.03-2.12 mm at the sixth abdominal segment.

Pseudocephalon (Figs 1-4 ). Antenna and maxillary palp on moderately developed lobe. Antenna with cylindrical base and apical knob. Maxillary palp bearing three papilla sensilla, two knob sensilla; dorsolateral group of sensilla bearing two well-developed papilla sensilla, aligned perpendicular to palp and surrounded by collar. Facial mask globular in lateral view. Preoral organ bearing three unbranched peg sensilla, located apically on simple elongate preoral lobe or on separate small cylindrical lobe (asymmetrical in Fig. 1 ) lateral to the mouthhook; three or four petal-like secondary lobes adjacent to preoral organ. Oral ridges in 12-14 rows, posterior margin finely serrate or entire; 15-17 accessory plates, posterior margin usually serrate, most oral ridges bordered with single accessory plate laterally, except anterior 2-5 plates in two series, plates much narrower than ridges. Labium triangular, anterior surface knobby (not clearly visible in Fig. 1 ), ventrally with two visible sensilla and tubercles.

Cephaloskeleton (Figs 5 - 7 ). Total length from tip of mouthhook to end of ventral cornu 1.31 mm. Mouthhook well sclerotized, black apically and basally; length a 0.28 mm; length b 0.22 mm; height c 0.20 mm; ratio a:b 1.29; ratio a:c 1.4. Tooth long, sharp, deeply concave ventrally, strongly curved, concave ventrally, ventral surface rough. Intermediate sclerite 0.22-0.23 mm long, 0.16 mm wide at ventral bridge. Epipharyngeal sclerite visible only in dorsal view, with medial lobe directed anteriorly. Labial sclerite robust, sclerotized in dorsal view. Parastomal bar extending for almost entire length of intermediate sclerite. Dorsal arch 0.35 mm high. Dorsal cornu with well-defined sclerotized area adjacent to notch, 0.50 mm long. Dorsal bridge prominently projecting anteriorly from dorsal cornu and slightly sclerotized. Anterior sclerite irregularly shaped and sclerotized. Cornu notch (N) 0.33 mm long and cornu notch index (N/DC) 0.7. Ventral cornu with poorly defined sclerotized area along edge of notch. Pharyngeal filter with weakly sclerotized anterior bar and eight ridges forming a series of grooves along length of ventral cornu. Ventral cornu 0.81 mm long from pharyngeal bar to posterior end of grooves. Ventral cornu 1.63 × as long as sclerotized area of dorsal cornu.

Thoracic and abdominal segments. Thoracic segments with dorsal spinules conical, symmetrical to slightly posteriorly curved; dorsal spinule pattern, as follows: T1 with 5-7 rows, forming scalloped plates; T2 with four or five rows; T3 lacking spinules; ventral spinule pattern as follows: T1 with 5-7 rows; T2 with 0-2 rows; T3 with two rows. Abdominal segments (A1-A8) lacking dorsal spinules; ventral creeping welts present on all abdominal segments; ventral spinule pattern as follows: A1 with six or seven rows; A2 with 10-12 rows; A3-A6 with 14-18 rows; A8 with 12-16 rows. Additional four or five discontinuous rows of spinules surrounding anal lobes, spinules all equally small, basally broad, distally sharply pointed, pointing away from anal lobes.

Prothoracic spiracle (Figs 8 , 9 ). Bilobed, bearing 24-27 tubules, distally rounded and arranged in a single, sinuous row laterally and double row medially. Spiracle distal width 0.35-0.36 mm; basal width 0.19 mm at junction with trachea.

Caudal segment (Figs 10 , 11 ). Dorsal tubercles and sensilla weakly developed, D1 distinctly anterior to D2. Intermediate tubercles (I1 and I2) moderately developed, I1 lateral and sometimes slightly dorsal to I2, associated sensilla weakly developed. Lateral (L1) tubercles, and associated sensilla weakly developed. Ventral (V1 and V2) tubercles and sensilla weakly developed, V1 distinctly posterior to V2. Anal lobe entire or grooved and moderately protuberant.

Posterior spiracle (Figs 10 , 12 , 13 ). Located above horizontal midline. Posterior spiracle openings with thick rimae and numerous trabeculae; 94-101 µm long; 35-37 µm wide; ratio length/width 2.68-2.72. Ecdysial scar apparent. Felt chamber oval, 190-191 µm in diameter at junction with trachea. Spiracular process SP-I comprising 4-9 trunks and 12-21 tips; ratio tips/trunks 2.3-3.0; basal width 9-12 µm; ratio basal width/length of spiracular opening 0.09-0.12. SP-II comprising three or four trunks and seven or eight tips. SP-III comprising 3-7 trunks and 6-12 tips. SP-IV comprising 3-7 trunks and 10-15 tips; ratio tips/trunks 2.14-3.33; basal width 9-10 µm; ratio basal width/length of spiracular opening 0.09-0.11.

Distribution.

Anastrepha aphelocentema is known only from Mexico (northern Veracruz and San Luis Potosí) ( Aluja et al. 2000; Norrbom 2004; Hernández-Ortiz 2007; CoFFHI 2020).

Biology.

This species was reared from fruit of Pouteria glomerata . It has been previously reared from fruits of Casimiroa edulis La Llave and Lex. ( Rutaceae ) ( Hernández-Ortiz 1992) and Pouteria glomerata ( Sapotaceae ) ( Stone 1942; Baker et al. 1944; Norrbom and Kim 1988; Aluja et al. 2000; Hernández-Ortiz 2007).

Molecular identification.

COI barcodes were generated from four larvae and submitted to GenBank (MT644043, MT654963-MT654965). These data further confirm the identity of the described larvae. K2P distances between A. aphelocentema larvae and the available adult sequence (KY428328) were less than one percent. BLAST searches were consistent with our new data, yielding only one good match: A. aphelocentema (99.84% sequence identity; KY428328). Additionally, all four barcodes returned consensus identifications of A. aphelocentema with three votes using the identity function in BarcodingR ( Moore et al. in press).

Figures

Figures 1 - 5. Scanning electron photomicrographs of third instar of Anastrepha aphelocentema 1 pseudocephalon 2 oral ridges 3 antenna and maxillary palp 4 preoral organ 5 ventral surface of mouthhook. Abbreviations: AN, antenna; MP, maxillary palp; PO, preoral organ; AP, accessory plates; OR, oral ridges; P 1 - P 3, papilla sensilla; K 1, K 2, knob sensilla; DS, dorsolateral papilla sensilla; PS, peg sensilla. Scale bars: 5 μm (4); 10 μm (3, 5); 20 μm (2); 100 μm (1).

Figures 6 - 11. Optical photomicrographs and scanning electron photomicrographs of third instar of Anastrepha aphelocentema 6 cephaloskeleton, lateral view 7 cephaloskeleton, dorsal view 8 prothoracic spiracle, lateral view 9 prothoracic spiracle, dorslateral view 10 caudal segment 11 anal lobe. Abbreviations: CS, total length of cephaloskeleton; MHa, mouthhook length a; MHb, mouthhook length b; MHc, mouthhook height c; IS, intermediate sclerite; DA, dorsal arch; DC, length of sclerotized area of dorsal cornu; N, notch; VC, length of ventral cornu; D 1, D 2, dorsal tubercles and sensilla; I 1, I 2, intermediate tubercles and sensilla; L 1, lateral tubercle and sensillum; V 1, V 2, ventral tubercles and sensilla. Scale bars: 50 μm (8); 100 μm (9, 11); 200 μm (6, 7); 500 μm (10).

Figures 12, 13. Scanning electron photomicrograph and optical photomicrograph of posterior spiracles of third instar of Anastrepha aphelocentema. Abbreviations: SP-I to SP-IV, spiracular processes. Scale bars: 50 μm (12, 13).