Small jewels: two new species of the rare genus

. A comprehensive review of the enigmatic genus Masona van Achterberg is provided. Two new species are described from the USA: Masona neon Dal Pos & Martens sp. nov. from Puerto Rico, and Masona wow Dal Pos & Martens sp. nov. from California. A key to the world species of Masona is presented, together with a discussion of the morphology of the genus and an annotated catalogue of the species. [ Masona ] timpaynei Quicke, 2019, is excluded from Braconidae and placed as incertae sedis in the Ichneumonidae, subfamily Neorhacodinae.

The position of the subfamily Masoninae within the superfamily Ichneumonoidea Latreille, 1802 has recently been a topic of debate.Originally, the subfamily was placed within the Braconidae, but Quicke et al. (2019a), based on the, at that time, unpublished phylogenetic data of Quicke et al. (2019b), moved Masoninae from the Braconidae into the sister family Ichneumonidae.However, the most recent classifi cation of the Braconidae by Jasso-Martínez et al. (2022) recovered Masona as sister to the aphidioid complex, thus transferring Masoninae back to the Braconidae.For the purposes of this paper, we are following the classifi cation presented by Jasso-Martinez et al. (2022) and retain Masoninae as a subfamily within the Braconidae.
In this contribution, we provide a review of the genus Masona with the description of two new species: Masona neon Dal Pos & Martens sp.nov., that represents the fi rst described extant species of the genus reported from the Caribbean, and Masona wow Dal Pos & Martens sp.nov., that represents the fi rst record of the genus from western North America.Moreover, Masona bulbofemoralis van Achterberg, 1995, is reported for the fi rst time for Florida based on the second specimen of the species collected since the original description.The taxonomic position of Masona timpaynei is reassessed, and the species is moved into the family Ichneumonidae and placed incertae sedis in the subfamily Neorhacodinae Hedicke, 1922, which is now recorded for Australia for the fi rst time.A comprehensive treatment of the extant species of Masona, with comments on the overall morphological features of the genus is provided, together with a key to the species of the world.

Morphological terminology follows
For each species, type information, material examined, and relevant comments are provided.Type localities are reported as they appeared in the original publication with the addition of the country of origin.Unavailable names are identifi ed in square brackets (as in Dal Pos et al. 2023).The genus of the original combination in species treated as incertae sedis are reported in square brackets.Metasomal tergites are reported abbreviated as T1 (fi rst metasomal tergite), T2 (second metasomal tergite), etc. 6. Head smooth, without processes (Fig. 10); pronotum not projecting into a fl ange, round (Fig. 10

Male
Unknown.

Remarks
The specimen reported above is a new record for Florida, expanding the distribution of the species further south, and it is the fi rst specimen recorded since the holotype was collected nearly 70 years ago.
The specimen was collected via Malaise trap at the ecotone between a cypress dome forested wetland and a palm fl at wood.During the wet season (June-September), the area is frequently inundated with water.The Malaise trap was left in situ for an entire year (August 2021-August 2022) but only a single specimen of M. bulbofemoralis was collected.The collecting period (5-26 June) matches the month of the holotype collection (22 June 1953).

Diff erential diagnosis
Masona infuscata can be easily distinguished from all the other species of the genus by the following morphological features:

Male
Unknown.

Remarks
Known only from the holotype.

Etymology
The species is dedicated to the National Ecological Observatory Network (NEON) project (https://www.neonscience.org/),which monitors ecosystems across the USA.This new species was collected as bycatch of a larger pitfall trap project used to monitor Carabidae (Coleoptera).Hopefully, it will serve as an incentive to strengthen collaboration between diff erent disciplines (e.g., ecology and taxonomy), and to increase awareness of the importance of biodiversity monitoring, especially in this period of dire biodiversity crisis.Taxonomy is still active, functional, and crucial for the study of biodiversity.The specifi c epithet ʻneonʼ is a noun in apposition.

H
. Prognathous, 1.2 × as long as wide, overall smooth and shiny; mandibles strongly twisted and blade-like; clypeus distinct, clearly separated form face, with small tentorial pits; face extremely reduced; occipital carina strong dorsally, gradually dissipating laterally; antenna with 11 fl agellomeres, all of which longer than wide, with apical fl agellomere 5 × as long as medially wide; scape and pedicel about as long as wide; area between antennal sockets not elevated.

M
. Overall smooth and shiny; 2.2 × as long as maximally wide.Pronotum shorter than mesoscutum and without a well-developed, lamelliform carina anteriorly; antescutal depression present.Propleuron convex ventrally, its posterior margin projecting into a point between fore coxae.Mesoscutum 0.8 × as long as wide, notauli absent.Scutellum distinct, approximately 6.0 × as wide as long medially.Mesopleuron smooth and shiny, with sternaulus distinct and reaching mid coxa; postpectal carina complete.Scutellum present.Metanotum indistinct.Propodeum smooth and shiny, widest at midlength, wider than mesoscutum, slightly convex (almost fl at) in lateral view, and produced into two blunt apophyses posteriorly; propodeal spiracle round.Metapleuron smooth and shiny, with juxtacoxal carina distinct.

C
. Entire body yellowish-white.

Male
Unknown.

Host
Unknown.

Distribution
UNITED STATES OF AMERICA: Puerto Rico (Fig. 3).

Remarks
The specimen was collected by means of a pitfall trap.The genus Masona has been previously recorded from the Caribbean (Dominican Republic) based on the fossil species Masona pyriceps van Achterberg, 2001.However, M. neon sp.nov.marks the fi rst record of an extant species for the area, and it is the fi rst record of the genus from the island of Puerto Rico.Quicke & Chaul, 2019 Figs 2A, 6A, 7-9

Diff erential diagnosis
Masona popeye can be easily distinguished from all the other species of the genus by the following morphological features: (1)

Male
Unknown.

Remarks
Known only from the holotype.

Diff erential diagnosis
Masona progantha can be easily distinguished from all the other species of the genus by the following morphological features:

Remarks
In the original description, there is an inconsistency in the number of males and females.van Achterberg (1995: 100) listed "6♂♂ & 2♀♀" among the paratypes of the species.However, when the author listed the full locality data for each specimen, the number of males amounts to seven and that of females to one.
Known only from the original type series, this species has an interesting distribution: all specimens were collected in the Florida Keys (in Monroe Co., Florida, USA), except for a single specimen collected in mainland Florida at the Archbold Biological Station (Highlands Co., Florida, USA).It is very possible that Masona prognatha is associated with the hammock hardwood forests present in South Florida, and this apparently disjunct distribution is mainly due to a lack of sampling in the greater Miami area, between the Florida Keys and the Archbold Biological Station, where hardwood forests are still present as remnants (Fernández-Triana, pers. comm.).van Achterberg, 1995 Fig. 4 Masona similis van Achterberg, 1995: 101-102 (description, key, distribution, images).

Diff erential diagnosis
Masona similis can be easily distinguished from all the other species of the genus by the following morphological features: (1) scutellum absent (present in M. bulbofemoralis, M. neon sp.nov., M. popeye); (2) fi rst fl agellomere about 2.5 × as long as medially wide (1.5

Remarks
Known only from the original type series.

Diff erential diagnosis
Masona wow sp.nov.can be easily distinguished from all the other species of the genus by the presence of two processes on the dorsal side of the head (absent in all the other species).Other morphological features are: (1) scutellum absent (present in M. bulbofemoralis, M. neon sp.nov., and M. popeye); (2) antenna as long as metasoma and head combined (longer in M. similis and M. infuscata); (3) precoxal sulcus present (absent in M. similis and M. infuscata); (4) occipital carina short, not reaching the ventral margin of the gena (well-developed in M. similis and M. infuscata).

Etymology
The specifi c epithet is a noun in apposition based on the common English expression ʻwowʼ, that means astonishment and / or admiration.The name refers to the fi rst author (DDP)'s reaction when he fi rst noticed the two unmistakable protuberances on the holotype's head as well as the surprise in discovering a new unmistakable species of this rare genus in the USA.tentorial pits; face extremely reduced; occipital carina strong dorsally, gradually dissipating laterally; antenna with 14 fl agellomeres, all of which longer than wide, with apical fl agellomere 2.2 × as long as medially wide; scape and pedicel about as long as wide; area between antennal sockets not elevated; dorsal side of head with two processes beyond middle.

M
. Overall smooth and shiny; 2.3 × as long as maximally wide.Pronotum shorter than mesoscutum and with a well-developed, lamelliform carina anteriorly; antescutal depression present.Propleuron convex ventrally, its posterior margin projecting into a point between fore coxae.Mesoscutum 0.9 × as long as wide, notauli absent.Scutellum distinct, approximately as long as medially wide.Mesopleuron smooth and shiny, with sternaulus distinct and reaching mid coxae.Scutellum absent.Metanotum indistinct.Propodeum smooth and shiny, widest at midlength, wider than mesoscutum, fl at in lateral view, and produced into two blunt apophyses posteriorly; propodeal spiracle round.Metapleuron smooth and shiny, with juxtaocoxal indistinct.

C
. Entire body yellow.

Male
Unknown.

Host
Unknown.

Distribution
UNITED STATES OF AMERICA: California (Fig. 13).

Remarks
Masona wow sp.nov.marks the fi rst record for the species of the genus from the western USA, and it is the fi rst species recorded with two processes on the head, the function of which is unknown.

Male
Described in the same work (Quicke et al. 2019b).

Remarks
In the original description, timpaynei was placed within Masona and distinguished from all the other species of the genus by the following morphological features: (1) wings present in females (absent in all the other species); (2) orthognathous head in females (prognathous in all the other species of the genus).This made timpaynei a morphologically unusual species for the genus.Based on the two diagnostic characters that set M. timpaynei apart from all the other species, Quicke et al. (2019b: appendix S1) redefi ned the diagnosis of the genus.A careful examination of the characters and the images in the original description led us to believe that timpaynei is not a species of Masona, nor does it belong to the family Braconidae.In addition to the two diagnostic characters listed to diagnose the species (see above), the presence of a pronounced dorsal notch on the terebra, and the conspicuous ovipositor sheaths, make it unlikely that timpaynei could be placed within the genus Masona.Moreover, the wing venation and the general habitus (e.g., large pedicel) renders timpaynei more similar to a member of the subfamily Neorhacodinae (Ichneumonidae).This also explains why in their phylogenetic analyses, Quicke et al. (2019b) retrieved Masona nested well within the Ichneumonidae, very diff erently from the results of Jasso-Martínez et al. (2022) who placed Masona well within Braconidae.
Even though the correct generic placement is still doubtful and cannot be securely proven without a direct study of the original type series, we can safely place timpaynei incertae sedis within the subfamily Neorhacodinae, as [Masona] timpaynei.The description of this species is of great interest still, as the fi rst record of the subfamily Neorhacodinae from Australia.

Current status
Incertae sedis in Neorhacodinae (this work).

Discussion
The scutellum of Masona Masona presents a very peculiar external anatomy, and one of the big divides between the species of the genus is the presence or absence of a scutellum.In their paper, Quicke et al. (2019a) considered the presence of a scutellum as a less derived state relative to its absence, and concluded that since only two species, Masona pyriceps and M. popeye, have a scutellum, then the origin of the subfamily is likely from the New World.However, in the light of the description of Masona wow Dal Pos & Martens sp.nov., this conclusion is no longer valid as the new species has a New World distribution but does not have a scutellum.Moreover, since the entire superfamily Ichneumonoidea suff ers from a lack of modern comprehensive comparative anatomical studies, it is diffi cult to understand if the structure identifi ed as a scutellum in Masona is actually a scutellum or a diff erent structure.In fact, within Apocrita Gerstaecker, 1867 there are two "scutella": the mesoscutellum (called simply scutellum in Ichneumonoidea) and the metascutellum (called postscutellum in Ichneumonoidea, and sometimes identifi ed as the entire metanotum) (e.g., Mikó et al. 2007;Vilhelmsen et al. 2010).The meso-and metascutellum are areas of the mesonotum and metanotum, respectively.They both accommodate circulatory organs connected to the posterior wing veins via the hollow scutellar arms, functioning as pulsating organs and facilitating the circulation of hemolymph through the wings (Vilhelmsen 2000;Mikó et al. 2007;Vilhelmsen et al. 2010;Pass 2018).Therefore, as species of Masona are mostly wingless, it is logical to expect a reduction or complete disappearance of the scutella (as is the case for M. prognatha, M. infuscata, M. similis and M. wow sp.nov.).The question remains as to why in some species the mesoscutellum is still present.We identifi ed two possibilities: (1) the mesoscutellum has lost its function as a pulsating organ, accompanied by a loss of the mesoscutello-metanotal muscle; or (2) the mesoscutellum has been incorrectly identifi ed as such and is a diff erent structure that occupies the same area of the mesoscutellum between the mesoscutum and the metapectal-propodeal complex.Further comparative analysis of the skeleto-musculature of Masona will be necessary to investigate the presence or absence of the mesoscutello-metanotal muscle as well as to align the terminology with the rest of the group.

Distribution and ecology
The overall distribution of Masona is scattered, with species known only from three biogeographical regions: Australasia, Nearctic, and Neotropical.However, both van Achterberg (1995) and Quicke et al. (2019a) reported the presence of two undescribed species from the Afrotropical and Indomalayan regions, respectively, and, in the CNC collection, there are specimens from Kenya and Madagascar (Fernández-Triana, pers. comm.).Although these species remain undescribed, when taken into consideration they create a more cosmopolitan distribution for the genus, which is then missing only from the Palaearctic region.As already underlined by Quicke et al. (2019a), more sampling of leaf-litter fauna should produce specimens and will ultimately be useful for fi lling the gaps in the distribution of this genus.
The host association and ecology of the species of Masona is entirely unknown.The known species have been collected mostly by Malaise or pitfall trap, and no direct observation or rearing from host has ever been reported.Masona prognatha appears to be associated with tropical hardwood hammocks, typical habitats of south Florida (Key islands included), while Masona bulbofemoralis is associated for the fi rst time with a Cypress dome, a common habitat in Florida and in the Atlantic and Gulf coastal plains, which is commonly fl ooded for 6-9 months a year (Casey & Ewel 1998).The new specimen of M. bulbofemoralis was collected at the ecotone of these habitats, during the summer period which is peak fl ooding season in Florida.The Australian species appears more associated with heathlands, and dense-canopied, mixed shrubland habitat that is typical of Australia.