﻿First record of subgenus Synaldis Foerster (Hymenoptera, Braconidae, Alysiinae, Dinotrema Foerster) from Chile, with description of ten new species

﻿Abstract Synaldis is a taxon within the Aspilota group with a contentious taxonomic history, currently classified as a subgenus of the genus Dinotrema. Species of Synaldis were only documented in the Neotropical region in 2017, and until then, the Neotropical fauna of this subgenus was represented by five species from Brazil. In this study, Synaldis is reported for the first time in Chile, with the description and illustration of ten new species, namely: Dinotrema (Synaldis) acarinareolatumsp. nov., D. (S.) brunneumsp. nov., D. (S.) chilensesp. nov., D. (S.) daltonisp. nov., D. (S.) flavumsp. nov., D. (S.) latusdentertiumsp. nov., D. (S.) perisfelipoisp. nov., D. (S.) pilosicaudatumsp. nov., D. (S.) puyehuesp. nov., and D. (S.) veraesp. nov. The studied specimens were collected during expeditions to southern Chile, in the Valdivian temperate rainforest at Parque Nacional de Puyehue. This study also includes a dichotomous identification key for Neotropical species of Synaldis, as well as a discussion of the primary morphological characters used to distinguish species within the Neotropical and Nearctic regions.


Introduction
The subfamily Alysiinae Leach, 1815 (Hymenoptera, Braconidae) contains koinobiont endoparasitoids exclusively of cyclorrhaphous Diptera larvae (Wharton 1984;van Achterberg 1993).Alysiinae is morphologically characterized by having exodont mandibles (outwardly directed, non-overlapping even when they are closed), and total loss of the occipital carina (van Achterberg 1993;Wharton 2017).This subfamily is subdivided into two tribes, Alysiini and Dacnusini, which differ by the presence of the fore wing vein r-m in Alysiini and its absence in Dacnusini (Shenefelt 1974;Yu et al. 2016).
Within Alysiini, the Aspilota group (sensu van Achterberg 1988) stands out as a remarkably large and complex group of genera.Members of this group are characterized by having a nearly glabrous apical portion of the ovipositor sheath, with its obtuse apex, and a host-spectrum nearly exclusively comprised ZooKeys 1206: 275-314 (2024), DOI: 10.3897/zookeys.1206.124515 Franciélle Dias de Oliveira & Angélica Maria Penteado-Dias: First record and new species of Synaldis in Chile of dipteran Phoridae.They are typically small, with a body length of 1-2 mm (less frequently ~ 3 mm), the body color is predominantly dark brown, and they are often found in decaying organic matter (van Achterberg 1988).
Two of the largest related genera in the Aspilota group, Dinotrema Foerster, 1863 and Aspilota Foerster, 1863 are morphologically distinguished by the size states of the paraclypeal fovea (anterior tentorial pit).In Dinotrema, this structure is small and clearly separated from the eye, whereas in Aspilota, the paraclypeal fovea is enlarged and almost reaching the margin of the eye (van Achterberg 1988).The genera Dinotrema, Aspilota, and related taxa are known for being among the most taxonomically complex within Braconidae.In addition to the predominantly small size of their representatives, the complexity is attributed to the limited characteristics used to distinguish species.Moreover, these diagnostic characters exhibit variability, sometimes significant, thereby obscuring the distinctions between closely related taxa (Belokobylskij and Tobias 2007).
Currently, the genus Dinotrema comprises three subgenera: the nominative Dinotrema, Synaldis Foerster, 1863, and Synaldotrema Belokobylskij & Tobias, 2002(Zhu et al. 2017).Synaldotrema is distinguished by its anomalous metasomal structure, i.e., clearly narrowed towards the apex (in lateral view), with the apical sternites (and ovipositor) distinctly retracted under the long and protruding apical tergites, and fourth tergite very elongate (Belokobylskij andTobias 2002, 2007).Synaldis differs from Dinotrema by the complete absence of vein 2-SR in the fore wing (consequently the first and second submarginal cells are confluents), while in the subgenus Dinotrema this vein is present, and the first and second submarginal cells are separated.
With a historically contentious taxonomic status, Synaldis was initially proposed as a genus by Foerster (1863).The generic validity of Synaldis has been questioned due to the variability in the reduction of certain veins among the Alysiini (Wharton 1980(Wharton , 2002)), including the 2-SR vein in specimens of the Aspilota group, as demonstrated by Koenig (1972).In 1988, van Achterberg re-established the genus Dinotrema and synonymized the species of "Synaldis" (having the paraclypeal fovea separated from the eye) with Dinotrema.Alternatively, Synaldis continued to be treated as a genus by several authors, and many species were either described in or transferred to it (Fischer 1993a(Fischer , 1993b(Fischer , 2003;;Papp 1996Papp , 2000;;Belokobylskij 2002Belokobylskij , 2004;;Peris-Felipo et al. 2014a;Peris-Felipo and Belokobylskij 2017).Finally, Zhu et al. (2017) proposed recognizing Synaldis as a subgenus of Dinotrema for convenience, until a comprehensive phylogenetic study of the genus Dinotrema can support the recognition of Synaldis as a subgenus or genus, a classification that was employed in this study.

Materials and methods
The nomenclature of wing venation follows van Achterberg (1993), and body sculpture follows Eady (1968).The other morphological terms and measurements were based on Peris-Felipo et al. (2014b), with additional explanations provided below.Body length: in lateral view, sum of the head extension (Fig. 1B, he+ew+tp), mesosoma length (Fig. 1F, msl), and metasoma length (Fig. 1K,  t1l+mtl).In dorsal view, head width is its maximum width (at eyes or temples), and head length is the midline between frons anteriorly and occiput.For head measurements in lateral view (Fig. 1B), the head was positioned to vertically align the upper base of the mandible with the lateral ocellus (following Wharton 1977).Paraclypeal fovea size: ratio between the maximum diameter of the fovea and the shortest distance from the fovea to the eye (short ≤ 0.40, middle = 0.45-0.55)(Fig. 1C).The mandible width is its maximum width (at apex or base) (Fig. 1D); diagonal carina refers to a carina arising from upper tooth (Fig. 9).Antenna length: sum of the lengths of its segments (Fig. 1E).The width of the first flagellar segment (F1) is its apical width, while for the other flagellomeres the width is their maximum width.Maxillary palp length: sum of the lengths of its segments.
Mesosoma width is the maximum width of mesoscutum; prescutellar depression (scutellar sulcus) width is its maximum width (Fig. 1G).Propodeal areola height and width were measured inside the areola (Fig. 1H).Propodeal spiracle size: ratio between the diameter of spiracle (at its outer margin) and the shortest distance from the spiracle to the basal margin of propodeum (small ≤ 0.3, middle = 0.35-0.50,large ≥ 0.55), in lateral view (Fig. 1F).Hind femur width is its maximum width and hind tibia width is its subapical width (Fig. 1I).Hind tarsus length: sum of the lengths of its segments.Metasoma length: sum of the first metasomal tergite (T1) length and the distance from anterior margin of the second tergite to the metasomal apex, in lateral view (Fig. 1K; t1l+mtl).Metasoma width is its maximum width in dorsal view (Fig. 1L).
Different types of propodeal sculpture and areolation are schematically represented in Fig. 3.The propodeal median longitudinal carina was considered incomplete when it is clearly interrupted (Fig. 3A, F, G), and complete when it crosses the propodeum from the basal to apical margin (Fig. 3B-D, H).Transverse carinae are incomplete when distinctly separated from the lateral parts (sides) of propodeum (Fig. 3A, B), and complete when they extend to the lateral of propodeum, at spiracle margin or lateral carina (Fig. 3C-H).The propodeal surface and the development of carinae were evaluated independently.For instance, the propodeum may exhibit a mainly smooth surface combined with poorly developed carinae (Fig. 3A), or a mainly smooth surface along with a distinct areola and complete carinae (Fig. 3H).A widely sculptured propodeum may exhibit distinct carination (as depicted in Fig. 3D), or the carinae may be lacking or indiscernible.
Digital scanning electronic microscope (SEM) photographs of uncoated specimens were taken with a FEI Quanta 250 SEM in a low vacuum mode.Color digital photographs were taken with a Leica M250C stereomicroscope, using a Leica MC170 HD camera and Leica Application Suite software v. 4.12.Measurements of the specimens were conducted using digital photographs taken with a Leica M165C stereomicroscope, Leica DFC295 HD camera, and Leica Application Suite software v. 3.7.Adobe Illustrator v. 24.1.2was utilized for illustrations, and Adobe Photoshop CS5 Extended v. 12.1.for minor adjustments to photographs and preparation of the plates.
Abbreviations used throughout the descriptions are as follows: POL post-ocellar line (shortest distance between lateral ocelli), OD ocellus diameter (maximum diameter of ocellus), OOL ocular-ocellar line (shortest distance between lateral ocellus and eye), F1 first flagellar segment, F2 second flagellar segment, F3 third flagellar segment, AF apical flagellar segment, T1 first metasomal tergite.Diagnosis.Mandibles tridentate, teeth of differing shape and length, sometimes upper tooth very small.Paraclypeal fovea small, clearly separated from eye.Precoxal sulcus always present.Pterostigma very long and narrow.Fore wing vein 2-SR always absent, resulting the first and second submarginal cells confluent; break between veins r and 3-SR absent.Vein cu-a often postfurcal, rarely almost interstitial.Metasoma with tergites not very narrowed apically in lateral view, apical sternites and ovipositor not strongly retracted under long apical tergites.

Taxonomic account
Hosts.Diptera larvae of the family Phoridae and possibly Drosophilidae.
Color: head, antennae, pronotum, mesoscutum and metasoma from the second tergite dark brown to brown.Mandibles and side of pronotum light brown.Remaining parts of mesosoma, legs, T1, and ovipositor yellowish.Wings hyaline, veins brown.
Male.Body length 1.6 mm.POL 1.3× OD, OOL 3.0× OD.Face 1.7× as wide as high, 2.1× as wide as clypeus.Clypeus 2.0× as wide as high.Mandible 1.4× as long as wide.Antenna with 18 segments, as long as body.F1 as long as F2.F2 2.0× as long as wide.F3 1.9× as long as wide.Maxillary palp as long as head height.Mesosoma 2.2× as long as wide.Prescutellar depression 1.8× as long as wide.Hind femur 4.2× as long as wide.Hind tibia 8.7× as long as wide.Metasoma 1.5× as long as mesosoma.
Etymology.The epithet is an adjective combining acarina (prefix a-indicating negation, with carina from Latin) and areolatum (derived from areola in Latin).The species name refers to the sculpture of propodeum, which lacks a median longitudinal carina and has a distinct areola (Figs 10,11). Distribution.Chile.
Comments.Based on its eye being shorter than temple, as well as its relatively thickened flagellomeres and legs, D. (S.) acarinareolatum sp.nov.appears to be related to the described here D. (S.) daltoni sp.nov., D. (S.) perisfelipoi sp.nov.and D. (S.) puyehue sp.nov., especially to the former.The differences between these species are given in the identification key.Diagnosis.This species differs from other New World species of Synaldis by the combination of the following characteristics: in lateral view, eye wider than temple (Fig. 17); paraclypeal fovea middle size (Fig. 14); mandible with three relatively large teeth, diagonal carina weak, mandibular apex wider than base; F1 2.7-3.3× as long as wide (Fig. 15); mesoscutal pit present, conspicuous (Fig. 16); propodeum with areola, median longitudinal carina and transverse carinae complete (Fig. 21); fore wing vein cu-a postfurcal, 1-CU1 shorter than cu-a (Fig. 18); hind tibia 9.8-10.3×as long as wide (Fig. 20).
Male.Body length 2.9 mm, fore wing 3.1 mm, hind wing 2.2 mm.POL 1.4× as OD, OOL 2.3× as OD.Eye 1.3× as wide as temple.Face 1.45× as long as high.Mandibular apex 1.1× as wide as base.Antenna with 25 segments, 1.1× as long as body.F1 3.3× as long as wide, 1.4× as long as F2.F3 2.3× as long as wide.AF 2.5× as long as wide.Propodeum rugose medially.Fore wing 3.1× as long as wide, vein 1-CU1 0.9× as long as cu-a.First subdiscal cell 2.6× as long as wide.Hind tibia 10.3× as long as wide.
Etymology.The epithet is an adjective derived from brunneus, which means brown in Latin.The species name refers to its predominantly brown body color .
Distribution.Chile.Diagnosis.This species differs from other New World species of Synaldis by the combination of the following characteristics: in lateral view, eye as wide as or slightly wider than temple (Fig. 31); mandible with three relatively large teeth, diagonal carina present, mandibular apex wider than base (Fig. 28); F1 2.8-3.2× as long as wide (Fig. 25); mesoscutal pit present, conspicuous; propodeum with areola, median longitudinal carina incomplete apically, transverse carinae complete (Fig. 27); fore wing vein cu-a distinctly postfurcal, 1-CU1 as long as or longer than cu-a (Fig. 29); hind tibia 9.0-9.4×as long as wide (Fig. 32).
Color: head brown to dark brown.Mesosoma light brown to yellow.Mandibles and legs yellowish.Antennae and metasoma brown to yellow.Wings hyaline to slightly darkened, veins light brown to brown.
Etymology.The name of species chilense is a gentilic adjective derived from Latin in reference to Chile, the country where this species was found.
Male.Face 1.5× as wide as high.Clypeus 1.85× as wide as high, slightly concave ventrally.Mandibular middle tooth acute; upper tooth ca as wide a lower, wider than middle tooth.Antenna with 20 segments, 1.1× as long as body.F1 as long as F2.F3 1.7× as long as wide.Mesosoma 1.9× as long as wide.Propodeal spiracle middle size, 0.5× distance from spiracle to base of propodeum.Fore wing 2.6× as long as wide, vein 1-SR absent, SR1 2.3× as long as (r+3-SR), 1-CU1 0.75× as long as cu-a, submarginal cell 2.05× as long as wide.Hind wing 5.6× as long as wide.Hind femur 4.2× as long as wide.First segment of hind tarsus 2.1× as long as second.Metasoma 1.4× as long as mesosoma.T1 with apex 1.6× as wide as base.Head, flagellum and metasoma from the second tergite brown; mandibles, scape, pedicel dark yellow; mesosoma, legs, and T1 yellow.
Etymology.The species name daltoni is a genitive noun, named in honor of Dalton de Souza Amorim, one of the collectors and who supplied the type material for this species. Distribution.Chile.
Color: mainly yellow, except head dorsally brown to light brown; mesosoma dorsally and flagellum yellow to light brown; metasoma from second tergite light brown; ovipositor sheath brown.Wings hyaline, veins light brown.

Male. Unknown.
Etymology.The epithet is an adjective derived from flavus, which means yellow in Latin.The species name refers to its predominantly yellow body color .
Color: Head brown to dark brown, except mandibles yellow, scape and pedicel brown to yellowish.Mesosoma brown to light brown, except scutellar disc and tegulae brown to yellow; propleuron, mesopleuron and propodeum orange to yellowish.Legs yellow.Metasoma brown except ovipositor yellow.Wings hyaline, veins brown. Male.Unknown.
Etymology.The epithet is an adjective derived from Latin, combining latus (wide), den (from dens, Latin for tooth), and tertius (third).The species name refers to its lower mandibular tooth wider than upper tooth (Fig. 57). Distribution.Chile.
Color: brown to yellow, except head dark brown to light brown, and legs entirely yellow or light brown from trochanter.Wings hyaline, veins brown to light brown.
Male.Head 1.9× as wide as long.Eye 1.5× as high as wide, 0.85× as wide as temple.Face 2.2× as wide as clypeus.Mandible without diagonal carina.Middle tooth acute.Antenna with 21 segments, 1.2× as long as body.F1 2.8× as long as wide.F2 2.5× as long as wide.F3 2.4× as long as wide.Mesosoma 2.0× as long as wide.Mesoscutal pit occupying 0.2× of mesoscutal length.Prescutellar depression 2.5× as long as wide.Precoxal sulcus almost smooth.Propodeum almost smooth, median longitudinal carina extending to mid-areola.Propodeal spiracle small, 0.25× distance from spiracle to base of propodeum.Fore wing 2.5× as long as wide.Submarginal cell 2.9× as long as wide.Hind femur 4.8× as long as wide.Hind tibia 9.2× as long as wide.Metasoma 1.5× as long as mesosoma.T1 2.4× as long as wide, apex 1.1× as wide as base.
Etymology.The species name perisfelipoi is a genitive noun, named in honor of Francisco Javier Peris Felipo, an expert in Alysiinae wasps, who has made significant contributions, particularly in his study of the genus Dinotrema.
Etymology.The epithet is an adjective combining pilosi (from pilosus, Latin for hairy), caudatum (from cauda, Latin for tail).The species name refers to its ovipositor sheath with several distinct, erect setae (Fig. 82).
Color: Head brown to dark brown, except mandibles, scape, and pedicel brown to light brown.Mesosoma light brown to yellow.Legs yellow.Metasoma brown, except T1 light brown and ovipositor yellow.Wings hyaline, veins brown.
Etymology.The name of species puyehue is a noun in apposition in reference to Parque Nacional de Puyehue, the type locality of the species.
Color: Head dorsally dark brown to brown.Face and clypeus brown to yellowish.Mandibles, antennae, and legs yellow.Mesosoma entirely yellow or parascutellar area and metanotum brown.Metasoma brown to light brown, except T1 brown to yellow and ovipositor yellow.Wings hyaline, veins brown.
Etymology.The species name verae is a genitive noun, named after Vera Cristina Silva, one of the collectors of the type material for this species. Distribution.Chile.
the development of propodeal transverse carinae and the shape of mandibles allow for the separation of two groups: one containing the species from Brazil, characterized by incomplete propodeal transverse carinae or mandibles with a very small upper tooth (Peris-Felipo and Belokobylskij 2017), and the other consisting of the species from Chile, distinguished by complete propodeal transverse carinae and mandibles with three relatively large teeth.The taxonomic importance of mouth parts in Alysiinae is well-established.Mandibles serve crucial functions in their biology, acting as levers, piercing, or cutting tools for parasitoid to escape from the host puparium and substrate, as well as manipulating substrates during host searching (Griffiths 1964;Wharton 1977Wharton , 2017)).
On the other hand, most species of Synaldis occurring in Nearctic region have mandibles widened towards the apex, with relatively large teeth, like Chilean species (Fischer 1967;Peris-Felipo and Belokobylskij 2017).These Nearctic species exhibit variable propodeal sculpture, but typically lack a distinct areola, differing from Chilean species, which have an areolate propodeum.The exception is D. (S.) glabrifovea.This species has an areolate propodeum, with complete median longitudinal and transverse carinae (as depicted in Fig. 3H).Considering its mandibular shape, propodeal sculpture, and relatively elongated flagellomeres, D. (S.) glabrifovea appears to be related to D. (S.) latusdentertium sp.nov.and D. (S.) pilosicaudatum sp.nov.Nevertheless, D. (S.) glabrifovea differs from the all the Neotropical species of Synaldis, including these last ones, by the absence of mesoscutal pit, among other distinguishing characteristics (Peris-Felipo and Belokobylskij 2017).
Differences in propodeal sculpture are commonly used to distinguish species in several genera of Alysiinae.Typically, the propodeum has a median areola with a short median longitudinal carina extending between the areola and its basal margin; however, various transformation series are observed, and in many taxa, the propodeal carination has been completely lost or only a few remnants of it remain.In some groups, the presence of a complete median longitudinal carina appears to result from the gradual narrowing of the areola (Wharton 2002).The ten new species described here have propodea with distinct areolae and complete transverse carinae.In D. (S.) latusdentertium sp.nov., D. (S.) perisfelipoi sp.nov., D. (S.) puyehue sp.nov., and D. (S.) verae sp.nov., the median longitudinal carina varied intraspecifically from incomplete to complete.Therefore, the development of this carina be carefully evaluated at both the specific and interspecific levels.In D. (S.) acarinareolatum sp.nov., the absence of any median longitudinal carina on the areolate propodeum is a notable characteristic.
The relative width of the eye and temple (in lateral view) is another useful character to distinguish some New World species of Synaldis.Most of these species have the eye as wide as or wider than temple, while other species have the eye clearly shorter than temple.In a few species, despite that, the temple varies from slightly wider to as wide as eye (Peris-Felipo and Belokobylskij 2017).Variations in wing veins and cells were also significant, especially in fore wing veins 1CU-1 (which affects the position of cu-a in relation to 1-M), 3-SR in relation to r-m, as well as the relative size of the marginal and submarginal cells.

Figure 3 .
Figure 3. Schematic representation of the various types of propodeal sculpture and areolation in New World species of Synaldis A propodeum with median longitudinal carina and transverse carinae incomplete, short B propodeum with median longitudinal carina complete and transverse carinae incomplete C propodeum mainly smooth, with median longitudinal carina and transverse carinae complete D propodeum mainly rugose, with median longitudinal carina and transverse carinae complete (areola absent) E propodeum with areola and transverse carinae complete (median longitudinal carina absent) F propodeum with areola and transverse carinae complete, median longitudinal carina incomplete, basal (not extending inside the areola) G propodeum with areola and transverse carinae complete, median longitudinal carina incomplete apically, reaching mid-areola H propodeum with areola, median longitudinal carina and transverse carinae complete.Abbreviations: lc -lateral carina, mlc -median longitudinal carina, ps -propodeal spiracle, tc -transverse carina.

Dinotrema (Synaldis) acarinareolatum sp. nov.
The subgenus Synaldis Foerster, 1863 from the genus Dinotrema is recorded in the fauna of Chile for the first time.