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Research Article
A new record of a winged stick insect (Phasmatodea) from Mexico, with a checklist and key to the species of the family Pseudophasmatidae from continental North America
expand article infoManuel de Luna, Roberto García-Barrios, Gerardo Cuéllar-Rodríguez, Ulises López-Mora§
‡ Universidad Autonoma de Nuevo Leon, San Nicolás de los Garza, Mexico
§ Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Abstract

The winged stick insect Metriophasma iphicles (Redtenbacher, 1906) (Phasmatodea: Pseudophasmatidae) is recorded for the first time from Mexico (state of Veracruz), making this the northernmost record of both the species and genus. A checklist of species in the family Pseudophasmatidae from Mexico and the USA is presented, and a key to the species listed is proposed. With the current record, the number of continental North American species of Phasmatodea increases to 108, and the number of genera in the region increases to 23.

Keywords

Metriophasma iphicles , neotropics, phasmid, Phasmida, Veracruz

Introduction

The order Phasmatodea (stick and leaf insects) is currently comprised of more than 3500 species worldwide (Brock et al. 2022). In continental North America (Canada, USA, and Mexico), this order is represented by 107 species, grouped into 22 genera and 7 (potentially distantly related) families (López-Mora and Llorente-Bousquets 2018, 2023, de Luna, in press). Among the North American phasmid fauna, there are records of only 5 winged species: 1 macropterous species of the genus Prisopus Peltier de Saint Fargeau & Audinet-Serville, 1827 (Prisopodidae: Prisopodinae: Prisopodini); 1 brachypterous species of the genus Haplopus Burmeister, 1838 (Phasmatidae: Cladomorphinae: Haplopodini); 2 brachypterous species of the genus Hypocyrtus Redtenbacher, 1908 (Phasmatidae: Cladomorphinae: Hesperophasmatini); and 1 macropterous species of the genus Agrostia Redtenbacher, 1906 (Pseudophasmatidae: Stratocleinae: Stratocleini). These winged species are mostly found in neotropical Mexico (Agrostia, Hypocyrtus, and Prisopus), but one is found in the southernmost state of the United States, Florida (Haplopus) (Arment 2006, López-Mora and Llorente-Bousquets 2018).

The family Pseudophasmatidae is of the “Areolatae” group, meaning that its species possess an area apicalis; this is a sunken and usually triangular-shaped areola found in the ventral apex of the middle and hind tibiae (Bradley and Galil 1977, López-Mora and Llorente-Bousquets 2018). This character distinguishes the members of this family from most of the taxa of the region, except the members of the family Timematidae from which they differ most prominently in the number of tarsal segments: 5 in Pseudophasmatidae (and all other families) and 3 in Timematidae. Another exception is the members of the family Prisopodidae, from which they differ in the aspect of the last abdominal segments being laterally expanded into lobes in Prisopodidae (López-Mora and Llorente-Bousquets 2018). This family is currently divided into 3 subfamilies and 7 tribes: Pseudophasmatinae with 3 tribes, Anisomorphini, Paraprisopodini, and Pseudophasmatini; Stratocleinae with 1 tribe, Stratocleini; and Xerosomatinae with 3 tribes, Prexaspini, Setosini, and Xerosomatini (Brock et al. 2022). Pseudophasmatidae is represented in continental North America by 6 species: the macropterous Agrostia rugicollis (Gray, 1835); 3 apterous species of the genus Anisomorpha Gray, 1835 (Pseudophasmatinae: Anisomorphini), Anisomorpha buprestoides (Houttuyn, 1813), Anisomorpha ferruginea (Palisot de Beauvois, 1805), and Anisomorpha paromalus Westwood, 1859; and 2 apterous species of the genus Autolyca Stål, 1875 (Pseudophasmatinae: Anisomorphini), Autolyca elena Gorochov & Berezin, 2008 and Autolyca pallidicornis Stal, 1875. Agrostia rugicollis, Anisomorpha paromalus, and both species of Autolyca are found in neotropical Mexico; the remaining 2 species of Anisomorpha are found in southeastern USA (Arment 2006, López-Mora and Llorente-Bousquets 2018, de Luna in press). Until now, the genus Agrostia was the only recorded winged genus of this family in the region (Arment 2006, López-Mora and Llorente-Bousquets 2018).

The genus Metriophasma Uvarov, 1940 (Pseudophasmatidae: Xerosomatinae: Prexaspini) contains 11 macropterous species that are distributed in the neotropical region. They are divided further into 2 subgenera: Acanthometriotes Hebard, 1924, which comprises 3 stocky species native of South America; and Metriophasma Uvarov, 1940, which comprises 8 elongated species native mostly to South America. At least 2 species, Metriophasma diocles (Westwood, 1859) and Metriophasma iphicles (Redtenbacher, 1906), have been recorded in Central America (Brock et al. 2022). In the present publication, Metriophasma iphicles is recorded for the first time in Mexico, being found in the state of Veracruz; this is currently the northernmost distribution record of any species of the genus. A checklist of the species of the family Pseudophasmatidae from continental North America is presented, and a key to all listed species is proposed.

Methods

During a visit (July 2022) to the Estacion de Biologia Tropical “Los Tuxtlas”, in the municipality of San Andres Tuxtla, state of Veracruz, Mexico, 8 specimens (7♂♂, 1♀) of a macropterous species of stick insect were collected at night (Fig. 1A). They were found perched on branches and vines, but there was no evidence indicating that the insects were feeding on these plants. The specimens were preserved individually in 70% ethanol and are kept at the Entomology Lab of the Facultad de Ciencias Forestales (FCF) of the Universidad Autonoma de Nuevo Leon (UANL) under the vouchers PHASM054–061, with 1 specimen being dry-mounted (PHASM056 – ♂ [Fig. 1B]) to obtain a better view of the pattern of the hindwings (Fig. 1B). Additionally, 3 other specimens from the same locality were examined; these are deposited in the Entomological Collection of the Estación de Biología Tropical “Los Tuxtlas” (EBTX45–47).

Fig. 1. 

Metriophasma iphicles, males. A. Live specimen found at night; wings spread; photo by Roberto García-Barrios; B. Dry-mounted specimen (PHASM056) with one tegmina and hindwing extended; photo by Manuel de Luna.

The keys of López-Mora and Llorente-Bousquets (2018) were employed in an attempt to identify the genus, the specimens keying to Perliodes (now a synonym of Agrostia). However, it was noted that the hindwings reached tergite IX (Figs 1B, 2A–C, 3A, C), while in Agrostia, it is known that the hindwings do not reach tergite VIII (Fig. 4A) (Aquino-Heleodoro et al. 2017). The presence of carinae in the middle and the hind femora was also noted, which are absent in all Stratocleinae including Agrostia (Zompro 2005). When the keys of Redtenbacher (1906) and Shelford (1909) were used instead, the specimens keyed to Metriotes (now a synonym of Metriophasma Uvarov, 1940), finding the same results when employing the key of Zompro (2005). After the genus was established, the keys to species present in the works of Redtenbacher (1906) and Shelford (1909) were employed, with the specimens keying to Metriophasma iphicles. Finally, the specimens were compared to photographs of the type material of Metriophasma iphicles from the Phasmida Species File website (Fig. 3A–C) (Brock et al. 2022), corroborating the identity of the collected material (Figs 1A, B, 2A–F).

Fig. 2. 

Metriophasma iphicles, abdominal segments VIII, IX, and X. A. Dorsal aspect, male; B. Lateral aspect, male; C. Ventral aspect, male; D. Dorsal aspect, female; E. Lateral aspect, female; F. Ventral aspect, female. Photos by Manuel de Luna.

Fig. 3. 

Metriophasma iphicles; photographs by Dr. Paul D. Brock, copyright Natural History Museum of London. A. Dorsal aspect, male paralectotype; B. Lateral aspect, male paralectotype; C. Dorsal aspect, female lectotype.

Fig. 4. 

Other North American representatives of the family Pseudophasmatidae; photographs by Dr. Paul D. Brock. A. Agrostia rugicollis, male syntype (type material of Perliodes nigrogranulosus, a synonym), copyright Naturhistorisches Museum Wien; B. Autolyca pallidicornis, male lectotype, copyright Naturhistorisches Museum Wien; C. Anisomorpha paromalus, male lectotype, copyright Natural History Museum of London.

Results and discussion

Checklist of species of Pseudophasmatidae from continental North America

The checklist includes records to state level, including those made or compiled by Redtenbacher (1906), Shelford (1909), Mariño and Marquez (1983), Conle and Hennemann (2002), Arment (2006), Gorochov and Berezin (2008), and López-Mora and Llorente-Bousquets (2018).

Family PSEUDOPHASMATIDAE Rehn, 1904

Subfamily Pseudophasmatinae Rehn, 1904

Tribe Anisomorphini Redtenbacher, 1906

Genus Anisomorpha Gray, 1835

1. Anisomorpha buprestoides (Houttuyn, 1813) USA (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Texas).

2. Anisomorpha ferruginea (Palisot de Beauvois, 1805) USA (Delaware, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, Nebraska [dubious record according to Arment 2006], Oklahoma, Pennsylvania, South Carolina, Texas, and Virginia).

3. Anisomorpha paromalus Westwood, 1859 MEXICO (Yucatan).

Genus Autolyca Stål, 1875

4. Autolyca elena Gorochov & Berezin, 2008 MEXICO (Chiapas).

5. Autolyca pallidicornis Stal, 1875 MEXICO (Chiapas).

Subfamily Stratocleinae Günther, 1953

Tribe Stratocleini Günther, 1953

Genus Agrostia Redtenbacher, 1906

6. Agrostia rugicollis (Gray, 1835) MEXICO (Colima).

Subfamily Xerosomatinae Bradley & Galil, 1977

Tribe Prexaspini Zompro, 2004

Genus Metriophasma Uvarov, 1940

7. Metriophasma iphicles (Redtenbacher, 1906) MEXICO (Veracruz). New record.

Material examined.—MEXICO • 1 ♀; Estación de Biología Tropical “Los Tuxtlas”, municipality of San Andres Tuxtla, state of Veracruz; 18.5848°N, -95.0741°W, 147 m a.s.l.; 25 July 2022; on branches and vines; Roberto García-Barrios and Manuel de Luna leg.; wet specimen (70% ethanol); collected under permit SGPA/DGVS/04352/22; voucher PHASM054 (FCF-UANL) • 1 ♂; same data; voucher PHASM055 (FCF-UANL) • 1 ♂; same data; dry-mounted specimen (Figs 2B, 3A–C); voucher PHASM056 (FCF-UANL) • 1 ♂; same data; voucher PHASM057 (FCF-UANL) • 1 ♂; same data; voucher PHASM058 (FCF-UANL) • 1 ♂; same data; voucher PHASM059 (FCF-UANL) • 1 ♂; same data; voucher PHASM060 (FCF-UANL) • 1 ♂; same data; voucher PHASM061 (FCF-UANL) • 1♀; same locality; 18.5831°N, -95.0741°W, 154 m a.s.l.; 24 September 2017; on Araceae; Ulises López Mora and Luis Rai Ruíz-Sánchez leg.; dry mounted; collected under permit SGPA/DGVS/03316/17; voucher EBTX45 (UNAM) • 1♀; same locality; 18.5847°N, -95.0735°W, 125 m a.s.l.; 25 September 2017; on Araceae; Ulises López Mora and Luis Rai Ruíz-Sánchez leg.; dry mounted; collected under permit SGPA/DGVS/03316/17; voucher EBTX46 (UNAM) • ♂; same locality; 18.5862°N, -95.0768°W, 170 m a.s.l.; 18 August 2018; on Araceae; Ulises López Mora leg.; dry mounted; collected under permit SGPA/DGVS/002646/18; voucher EBTX47 (UNAM).

New diagnosis.Metriophasma has an area apicalis in the middle and hind tibiae, unlike all Diapheromeridae, Parabacillus Caudell, 1903, and Phasmatidae. It possesses 5-segmented tarsi, unlike the Timematidae. Metriophasma differs from all the North American genera, except 4 others, in having wings: the wings of Metriophasma are well-developed, unlike in the brachypterous species of Haplopus and Hypocyrtus (Phasmatidae). The abdomen of Metriophasma is not strongly lobed distally, as seen in macropterous species of Prisopus (Prisopodidae). Finally, Metriophasma has carinae on the ventral side of the middle and hind femora; these are lacking in all Stratocleinae, including Agrostia (Pseudophasmatidae) (Bradley and Galil 1977, Zompro 2005).

Metriophasma iphicles differs from the 3 species included in the subgenus Acanthometriotes for its elongated body and in having mesonotal carinae (Hebard 1924); from Metriophasma armatum (Redtenbacher, 1906), Metriophasma baculus (De Geer, 1773), and Metriophasma stollii (Gray, 1835) in having tubercles instead of spines in the dorsal aspect of the mesonotum (Redtenbacher 1906); from Metriophasma agathocles (Stål, 1875), Metriophasma baculus, and Metriophasma diocles in having concolorous hindwings (Redtenbacher 1906, Shelford 1909); and from Metriophasma pericles (Redtenbacher, 1906) in not having a median carina in the mesonotum (Redtenbacher 1906).

This is the first time a species of the genus Metriophasma has been recorded for Mexico. The current record increases the number of species in continental North America to 108, the number of species of North American Pseudophasmatidae to 7, and the number of genera of the region to 23. Metriophasma iphicles had been previously recorded in the Central American countries of Honduras and Panama (Redtenbacher 1906, Shelford 1909), being the northernmost record of the species and genus. It is likely that this genus originated in South America, as this is where the majority of its species are found. At least 2 species reached Central America: Metiophasma diocles and Metriophasma iphicles. Following the tropical and subtropical areas found in the Atlantic versant, a population of Metriophasma iphicles reached Veracruz (Fig. 5). This distribution and tropical migration pathway has been observed in other animals, even those with low vagility, such as pit vipers (Saldarriága-Córdoba et al. 2017), so it is not surprising that a winged species could have easily followed it. The presence of this species is expected in more southern states, such as Chiapas or Oaxaca, as well as in northern Central American countries, such as Guatemala and Belize. Recently, there have been several instances of cryptic diversity in Phasmatodea; therefore, further molecular and morphological (internal genitalia) studies should follow to confirm whether this disjunct population is indeed Metriophasma iphicles or a closely related but undescribed species of the same species complex.

Fig. 5. 

Map of Mexico; pink circle points to the new record of Metriophasma iphicles.

Key to the North American Pseudophasmatidae

The following key works in adults of any sex from either the USA or Mexico. It follows keys and descriptions present in the works of Redtenbacher (1906), Shelford (1909), Conle and Hennemann (2002), Zompro (2005), Gorochov and Berezin (2008), and López-Mora and Llorente-Bousquets (2018). Care must be taken when examining specimens from neotropical Mexico, as some taxa might still be unreported or undescribed for this region.

1 Macropterous (tegmina reduced, hindwings well-developed, capable of flight) [Figs 1A, B, 3A–C, 4A] 2
Apterous (completely wingless and flightless) [Fig. 4B, C] 3
2 Hindwings reaching the ninth abdominal tergite [Figs 1B, 3A–C]; middle and hind femora with a ventral carina. In the region, it has only been recorded in southeastern Mexico (Veracruz) Metriophasma iphicles
Hindwings shorter, not reaching the eighth abdominal tergite [Fig. 4A]; middle and hind femora without ventral carina. In the region, it has only been recorded in southwestern Mexico (Colima) Agrostia rugicollis
3 Body concolorous [Fig. 4B] (juveniles can be speckled); forefemur mostly straight [Fig. 4B]. ♂♂ with ninth abdominal tergite with forcep-like lobes; ♀♀ subgenital plate large, reaching the tip of the anal segment or surpassing it. Found in southernmost Mexico Autolyca *: 4
Body striped (sometimes faded, but nonetheless visible) [Fig. 4C]; forefemur depressed and curved basally [Fig. 4C]. ♂♂ with small, non-convex poculum; ♀♀ subgenital plate short, reaching, at max, halfway the anal segment. Found in southeastern USA as well as the Yucatan Penninsula in Mexico Anisomorpha : 5
4 ♀♀ operculum with rounded apex; ♂♂ genital plate apex bifurcated with 2 tubercle-like projections Autolyca elena
♀♀ operculum with angular apex; ♂♂ genital plate apex entire Autolyca pallidicornis
5 Pronotum slightly wider than long; ♂♂ mesonotum 1.8 times larger than wide, at max; ♀♀ mesonotum 1.4 times larger than wide, at max. Found in the Mexican Yucatan Penninsula Anisomorpha paromalus
Pronotum slightly longer than wide; ♂♂ mesonotum 2.4 times larger than wide, at minimum; ♀♀ mesonotum 1.6 times larger than wide, at minimum. Found in southeastern USA 6
6 Middle mesonotal suture clearly visible; with a distinctive black stripe that runs from the head to abdominal tergite X; ♂♂ tergite X with a concave prolateral incision, ♂♂ total body length 38–50 mm, ♀♀ total body length 58–85 mm Anisomorpha buprestoides
Middle mesonotal suture not clearly defined; with a discontinuous and not clearly defined black stripe that usually runs from the head to abdominal tergite IX, although it can appear as a faint line in tergite X; ♂♂ tergite X without incisions; ♂♂ total body length 22–35 mm; ♀♀ total body length 40–55 mm Anisomorpha ferruginea

Remarks on Autolyca: Some authors have stated that “the known representatives of Autolyca are invariably apterous” (Conle et al. 2009), which holds true for the majority of the described species. However, Autolyca albifrons Redtenbacher, 1906 was described to possess brachypterous hindwings but not tegmina (Redtenbacher 1906). The origin of the lone male holotype is unknown but is unlikely to be from New Caledonia (Redtenbacher even marked this dubious locality with “(?)”). Much more recently, Bank and Bradler (2022) mentioned an undescribed brachypterous species of Autolyca from Panama. The revision and redescription of the holotype of Autolyca albifrons, the collection of more material, and the description of the undescribed Panamanian Autolyca are needed to begin resolving this matter.

Acknowledgements

We want to thank Dr. Paul D. Brock and the Phasmida Species File Website as well as the Naturhistorisches Museum Wien and the Natural History Museum of London for providing us with some of the photographs used in the current publication. We also want to thank Biol. Rosamond Iones Coates and Biol. Martha Madora-Astudillo for their help at the station and our friends and colleagues David Ortega, Biol. Nora Niño, Edilia López, Victor Olivares, and Victor Hernández for their help during fieldwork. Our gratitude extends to the anonymous reviewers for their hard work. Lastly, we would like to thank The Orthopterists’ Society for their support in the publication of this article.

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