Research Article |
Corresponding author: Gerardo Rivas ( gerard.rivas@gmail.com ) Academic editor: Robin Thomson
© 2022 Mauricio Ramírez-Carmona, Rafael Barba-Álvarez, Atilano Contreras-Ramos, Gerardo Rivas.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ramírez-Carmona M, Barba-Álvarez R, Contreras-Ramos A, Rivas G (2022) Larval and female descriptions of Mejicanotrichia Harris & Holzenthal, 1997 (Trichoptera, Hydroptilidae, Leucotrichiinae) from Mexico. In: Pauls SU, Thomson R, Rázuri-Gonzales E (Eds) Special Issue in Honor of Ralph W. Holzenthal for a Lifelong Contribution to Trichoptera Systematics. ZooKeys 1111: 355-369. https://doi.org/10.3897/zookeys.1111.77413
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Mejicanotrichia Harris & Holzenthal, 1997 is a small genus of Hydroptilidae (Trichoptera), which consists of seven species, six of them distributed in Mexico, and one more in Guatemala. Larval descriptions of only two species (M. blantoni and M. estaquillosa) were previously known, as well as only females of three species (M. blantoni, M. estaquillosa, and M. tamaza) previously described. The present study provides descriptions of the larvae of M. harrisi and M. tridentata, as well as a description of the female of M. harrisi. Identification keys for adult males, known females, and known larvae are also provided. This work aims to incorporate more information into the taxonomy of the genus, its ecology, and facilitate additional characters of potential use in future phylogenetic studies.
Biodiversity, caddisflies, immature stages, madicolous habitat, Neotropics, water quality
Hydroptilidae represents the most diverse family of the order Trichoptera, currently with 2,570 species recorded worldwide (
The larvae of this genus are characterized by having numerous, broad, and largely colorless setae on the dorsoventrally flattened body, with oval shaped sclerites on the prosternum and the divided meso- and metathorax. The body exhibits an ornamentation with pigmented points on the surface of the thorax and abdomen; the legs are of the same size and shape, with tarsal claws well developed, as well as anal prolegs prominent, square shaped, each with a simple large claw (
Thus, the aim of this study is to contribute to the knowledge of Mejicanotrichia, particularly larvae and females of the Mexican species, as well as to provide an environmental characterization of the larval habitat of the genus. We gladly dedicate this contribution to Dr. Ralph W. Holzenthal of the University of Minnesota, with our admiration as one of the main experts of Neotropical aquatic entomology, particularly in recognition to his dedication for the study of caddisfly biodiversity in Latin America.
Specimens of Mejicanotrichia harrisi and M. tridentata (
The morphological terminology used is based on
25 larvae (IN-TR-00221). Mexico, Guerrero, Tonalapa del Río, Tonalapa River, near the Atlmolonga “balneario” (780 m a.s.l., 18°20'57.05"N, 99°42'10.12"W), 25 January 2020; leg. M. Ramírez-Carmona and O. Lagunas-Calvo.
Abdomen mainly membranous with presence of abdominal tergites and fine pigment spots (Fig.
Dorsoventrally depressed body, range length: 1.9–2.1 mm, covered extensively by colorless and thick setae (Fig.
Head.
Dark brown, prognathous, without visible ecdysial sutures. Antennae simple (Fig.
Thorax.
Pro-, meso-, and metanotum divided by a median ecdysial line (Fig.
Abdomen.
Long and wide, gradually tapering posteriorly. Venter with thick and extremely short setae irregularly distributed on surface. Segments I–VIII with well developed, short and wide tergites, covering much of each notum, those on segment I differing noticeably in size and shape from remainder. All tergites with thick and short colorless setae. Tergite I divided in two by a median line, with two thin and dark setae on the anterior margin. Tergites II–VII with medial lacunae and two fine and dark setae in the posterolateral margin (Figs
The specimens were collected at a water temperature of 19 °C; with pH between 7.8–8.4; water presented a hardness of 171 mg CaCO3/l; the dissolved oxygen was 7.6 mg/l and 89% of oxygen saturation.
5 females (IN-TR-00220). Mexico, Guerrero, Tonalapa del Río, Tonalapa River, near the Atlmolonga “balneario” (780 m a.s.l, 18°20'57.05"N, 99°42'10.12"W), 25 January 2020; leg. M. Ramírez-Carmona and O. Lagunas-Calvo.
Unmodified antennae, hindwings lacking patches of scales, as in M. rara, with a body length of 2 mm. Abdominal segment VI without sternite process.
Dark brown coloration (Fig.
Head.
Antennae simple, 17-segmented, scape slightly longer than flagellum; three ocelli present (Fig.
Thorax. Wings with reduced venation, mesoscutellum with a transverse line and subrectangular metascutellum. Tibial formula (0, 2, 4). Legs unmodified.
Abdomen.
Segment VII elongated, without processes on sternite. Segment VIII short and ring-shaped, with a fringe of setae on posterior margin and a pair of apodemes extending anteriorly. Segment IX short, with pair of apodemes originating on posterolateral margin and extending anteriorly just before anterior margin of segment VII. Segment X rounded apically, with pair of lateral papillae (Fig.
The specimens exhibit a keyhole-shaped opening in the bursa copulatrix, which occurs in the other species of the genus. On the other hand, females of M. harrisi differ from those of other species because of the presence of two short and membranous lobes that extend posteriorly, as well as for having a shield-shaped posterior sclerite (Fig.
15 larvae (IN-TR-00222). Mexico, Chiapas, Ixhuatán, 95 km 2.8 N Ixhuatán, tributary of the Teapa River (409 m a.s.l., 17°18'41.06"N, 93°0'17.78"W), 18 April 2019; leg. M. Ramírez-Carmona, O. Lagunas-Calvo and G. Rivas-Lechuga.
Body mostly membranous ventrally. Thorax reddish-brown with dark spots dorsally. Abdominal tergites with dark and irregular spots (Fig.
Body dorsoventrally depressed, range length 2.0–2.3 mm, widely covered with thick, long, and colorless setae (Fig.
Head. Ocherous-brown, prognathous, without visible ecdysial sutures.
Thorax.
Pro-, meso-, and metanotum divided longitudinally by a medial ecdysial line. Three thoracic nota each with two lateral processes, which have two thick and opaque setae. Pronotum widening posteriorly. Anterior margin of pronotum with a ridge of thick setae, anterolateral corners folding ventrally. Anterior portion of pronotum slightly covering back of the head (Figs
Abdomen.
Long and widened, narrowing posteriorly. Ventral region with irregularly distributed, thick, short setae. Segments I–VIII with dorsal tergites, largely covering dorsum of each segment; first sclerite divided longitudinally. Tergites II–VII with lacunae in middle and beyond posterior margin (Fig.
The specimens were collected at a water temperature of 25 °C; with pH between 7.8–8.4; water presented a hardness of 136.8 mg CaCO3/l; the dissolved oxygen was 4.5 mg/l and 57% of oxygen saturation.
1 | Phallus with apical or subapical spines | 2 |
– | Phallus without apical or subapical spines ( |
M. harrisi |
2 | Phallus with three pairs of spines apically ( |
3 |
– | Phallus with two pairs or less of apical or subapical spines ( |
4 |
3 | Phallus apically with three pairs of elongate lateral spines and a central spine ( |
M. estaquillosa |
– | Phallus apically with three pairs of short spines and a pair of short lateral spines subapically ( |
M. blantoni |
4 | Phallus apically with two pairs of elongate spines | 5 |
– | Phallus apically without spines ( |
6 |
5 | Phallus apically with a pair of elongate, weak spines laterally, pair of thin spines mesally and subapically with a pair of spicule bearing tergites ( |
M. tamaza |
– | Phallus apically with two pairs of elongate spines, without a subapical pair of spicules bearing tergites ( |
M. tridentata |
6 | Phallus subapically with a pair of lateral spines, with ejaculatory duct emerging between spines ( |
M. trifida |
– | Phallus subapically with a pair of thin, elongate spines laterally, without ejaculatory duct emerging between spines ( |
M. rara |
1 | Bursa copulatrix with two membranous lobes (Fig. |
2 |
– | Bursa copulatrix with one membranous lobe ( |
M. tamaza |
2 | Bursa copulatrix with keyhole-structure, with keyhole-shaped sclerite mesally (Fig. |
3 |
– | Bursa copulatrix without keyhole-structure, with oval sclerite mesally ( |
M. estaquillosa |
3 | Bursa copulatrix with shield-shaped sclerite (Fig. |
M. harrisi |
– | Bursa copulatrix without shield-shaped sclerite ( |
M. blantoni |
1 | Fine pigments in posterior margin of abdominal tergites without pattern in pairs (Fig. |
2 |
– | Fine pigments in posterior margin of abdominal tergites with pattern in pairs (Figs |
M. tridentata |
2 | Propleural sclerite with rounded shape, claw-shaped or triangle-shaped ( |
3 |
– | Propleural sclerite not round-shaped, instead serrate tooth shaped (Fig. |
M. harrisi |
3 | Tergites without a blotched pattern over the body, propleural sclerite triangle-shaped ( |
M. blantoni |
– | Tergites with a blotched pattern over the body, propleural sclerite claw-shaped ( |
M. estaquillosa |
The genus Mejicanotrichia is a Mesoamerican taxon with species distributed in a restricted fashion, both regarding a specific microhabitat, as well as a narrow geographical area. Knowledge of these species is practically limited to morphology of the adult males. The present work increases the knowledge of the larvae and we also contribute the description of the female of one species: Mejicanotrichia harrisi was originally described from the Temazcalapa River, in the state of Guerrero, with specimens collected between 1994 and 1995. We attempted to recover specimens from the original locality, but the stream was found to be completely dry. It was at a tributary of the Tonalapa River, 10 km away from the type locality, that adult (females and males) and larval specimens of M. harrisi were collected (Fig.
The larvae of M. harrisi, M. tridentata, and those described in previous studies differ from each other in the shape of the propleural sclerite (Figs
Species delimitation in Trichoptera is based entirely on primary characters presented by male genitalia, as these are conspicuous and complex (
Some of the ecological affinities of the genus have resulted in morphological adaptations to the habitat, as referred to by
Much of the flora of madicolous habitats is restricted to microalgae, which are mostly diatoms or patches of filamentous algae (
MRC thanks Joaquín Bueno-Soria for his valuable comments and advice, as well as for sharing literature for the advancement of this manuscript. He also thanks Allan Paulo Moreira Santos, Juan José Morrone, and Javier Alcocer Durand for their comments, suggestions, and review of the preliminary project and for his ideas shared in correspondence. We also thank Omar Lagunas Calvo and José Antonio Olayo Jaimes for their valuable help on collecting trips. Likewise, we wish to thank Laura Gómez Lizárraga (SAMEB-ICMyL-UNAM) for her support in taking electron microscopy photos. MRC is grateful to Posgrado en Ciencias del Mar y Limnología, UNAM, and Mexico’s Consejo Nacional de Ciencia y Tecnología (CONACYT) for a scholarship granted during his master’s degree.