Tricorythodes sordidus Allen, 1967

Baumgardner, David E. & Ávila, Socorro, 2006, Cabecar serratus, a new genus and species of leptohyphid mayfly from Central America, and description of the imaginal stages of Tricorythodes sordidus Allen (Ephemeroptera: Leptohyphidae), Zootaxa 1187 (1), pp. 47-59 : 54-57

Tricorythodes sordidus Allen

Tricorythodes sordidus was described by Allen (1967) based upon larvae collected from San Jose Province in Costa Rica. The species has also recently been documented from Guatemala ( McCafferty et al. 2004). Records given below further document the species, for the first time, from México and Nicaragua.

Although Allen (1967) did not discuss in detail how this species differed from other species of Tricorythodes , the long setae on the head and thorax, and its general body coloration distinguish it from other Tricorythodes larvae. The holotype is presently deposited at Florida A&M University (Tallahassee), and is in good condition. The holotype label bears the name “ Tricorythodes caenosus ”, as do four paratypes deposited at the California Academy of Sciences and eight paratypes deposited at Purdue University (Luke Jacobus, personal communication). An additional paratype, also deposited at Florida A&M University, bears a label with the name “ Tricorythodes casnosus ”. Evidently, both of these names are manuscript names used at some point by Allen. The locality labels in the vials correspond exactly with the locations given for T. sordidus in the original description. In addition, the specimens agree well with the original description, and all are considered here to belong to the original type series of T. sordidus . All of these specimens and specimen vials have been relabeled to indicate that they all belong to the types series of T. sordidus , and have been returned to their respective institutions. The following imago description is based upon 3 reared males and 7 reared females from Domitalia Field Station in Nicaragua, and Las Cruces Biological Station in Costa Rica.

Male imago. Body length: 3.0–3.5 mm. Forewing length 2.5–3.0 mm. Hindwing absent. Cercus and median caudal filament length 8.0–9.0 mm.

Head: pale to pale reddish brown with diffuse overshadings of black dorsally; compound eyes small, widely separated; diameter of one eye less than distance between eyes; lateral ocelli black at base, clear in distal one­third; median ocellus mostly clear; antenna white with black stippling.

Thorax: prothorax pale with extensive overshadings of black dorsally; meso­ and metanota pale brown to reddish brown with diffuse overshadings of black stippling; lateral margins pale with black stippling; membranous filaments on mesoscutellum (plumidium) absent. Femur: pale to pale reddish brown with very limited black overshading; foretibia white to pale gray with black over shading; foretarsus pale, three­fourths length of foretibia; meso­ and metatibia pale reddish brown with black stippling and median pale area; claws similar and blunt; hindfemur less than three­fourths length of hindtibia and handtarsus combined. Forewings: translucent, margin opaque; costa, subcosta, and R1 purplish brown for one­half to three­quarters their length; subcosta heavily pigmented purplish­brown beyond margin of vein; vein ICu1 joined basally with vein A, forming a triad where veins CuP and ICu2 are included; vein CuP present, not converging with vein A; vein ICu2 present, detached from ICu1.

Abdomen: pale yellow with moderate to extensive black overshading; terga II­VI with pale median line; sternites pale with black stippling limited to margins; cerci pale gray, bases with black stippling. Genitalia (Fig. 16): penes broad, fused for most of their distance, with shallow distomedial emargination; subgenital plate with moderately deep emargination; forceps three segmented, second segment with a basal swelling; segment one of forceps about as long as segments two and three combined.

Female imago. Body length: 3.0–3.5 mm. Forewing length 2.5–3.0 mm. Hind wing absent. Cercus length 1.0–1.5 mm. Median caudal filament 2.0–2.5 mm.

Head: pale yellow with diffuse overshadings of black dorsally; shading most intense at base of ocelli and between compound eyes; compound eyes small, widely separated; diameter of one eye less than distance between eyes; lateral and median ocelli black at base, clear in distal one­third; antenna white.

Thorax: prothorax pale with extensive overshadings of black dorsally; meso­ and metanotam reddish brown with black stippling medially and laterally; sterna pale yellow to white, margins light brown. Femur: white, margins reddish brown with black stippling; tibia and tarsus pale reddish brown. Forewings as in male.

Abdomen: tergites I­VIII yellow, IX and X pale yellow to white; dorsally with extensive black stippling forming transverse black bands; sternites pale yellow; subgential plate triangular with posterior margin rounded; cercus and median caudal filament pale gray.

Discussion: Adults of Tricorythodes sordidus fit within the concepts of Tricorythodes given by both Molineri (2002) and Wiersema and McCafferty (2000), including characters of the male genitalia (number and relative length of forceps and shape of penes), absence of hindwings, and vein ICu 1 joined basally with vein A forming a triad where veins CuP and ICu 2 are included.

Currently, there are only two species of Tricorythodes known from Central America: T. sordidus and T. costaricanus (Ulmer) . The holotype of T. costaricanus is based on a female imago deposited in the Bavarian State Collection, Zoology, Munich, Germany (Ernst­Gerhard Burmeister, personal communication). Because of the extremely fragile nature of the dried and pinned holotype, it was not available to be mailed for detailed study. However, Dr. Burmeister did provide pictures of the holotype and associated labels, which were sufficient for comparison with T. sordidus . The holotype is in relatively good condition with all three body regions, wings, and at least some of the legs, present and intact. The type locality of T. costaricanus , written on a label associated with the holotype, is “ San José, Costa Rica ”. No other specific information was given on the label.

Although T. sordidus was collected from the same province in Costa Rica as the holotype of T. costaricanus , it does not appear that T. sordidus is a synonym of T costaricanus . First, females of T. costaricanus are a little larger and described as possessing caudal filaments measuring about 3 mm in length, while females of T. sordidus have relatively short cerci (half to a little more than half length of caudal filament). Second, T. costaricanus has a body which is generally brown to dark brown in color. Tricorythodes sordidus adults are much paler, with a thorax which is more pale brown than T. costaricanus , and an abdomen which is generally pale yellow with moderate to extensive black shading. These characters should easily distinguish T. sordidus from T. costaricanus in the adult stage of both genders.

Distribution and Biology: Tricorythodes sordidus appears to be widely distributed and common in Latin America. It is known from northeastern Mexico south to Costa Rica. Larvae can be found in a wide variety of lotic habitats, from smaller creeks to large rivers, and are usually extensively covered with sediment.

Type Material Examined: HOLOTYPE: Tricorythodes sordidus Allen ; COSTA RICA: San Jose Prov.: San Jose, 9­viii­62, G.G. Musser [ FSCA ( FAMU)— E2003.1 T] . HOLOTYPE: Tricorythodes costaricanus (Ulmer) ; COSTA RICA: San Jose [Bavarian State Collection, Zoology, Munich, Germany] (electronic images of holotype only examined) .

Other Type Material Examined: PARATYPES: 4 larvae, same data as holotype ( CAS), originally designated paratopotypes. COSTA RICA: stream 11 mi. SE San Isidro del General , 200 ft., 22­vii­1962, G.G. Musser , 1 larva, 4 associated slides [ FSCA ( FAMU) ­ E2003 . T] .

Material Examined Not Belonging to Type Series: All specimens deposited at TAMU unless otherwise indicated. COSTA RICA: Alajuela Prov.: NE of Bijagua, nr. Las Flores, Río Areuo (10°21’06”N; 85°21’05”W), 07.vi.2000, 2L, WDS ; 3 km SE Rio Cuarto, Hwy. 140, Río Hule (10°20’N; 84°12’W), 15.i.2000, 1L, WDS . Guanacaste Prov.: 4.8 km N Canas, Hwy. 142, Río Santa Rosa , 17.i.2000, 4L, WDS ; Río Diria at unnamed road, ca. 1 Km. E of intersection with Hwy 21, (10°20’05”N; 85°34’04”W), 15.vi.2001, 3L, DEB ; 6 km S San Miguel, Hwy 1, Quebrada Culvert (10°19’N; 85°03’W), 23.i.2000, 3L, WDS ; unnamed creek at Hwy. 18, ca. 8 Km NW Nicoya (10°10’00”N; 85°26’08”W), 16.vi.2001, 2L, DEB . Heredia Prov: unnamed creek at Hwy 4, ca. 3 Km from jct. with Hwy 32 (10°15’10”N; 83°55’11”W), 10.vi.2001, 2L, DEB . Limón Prov.: Río Catarata at Hwy 36, 4 Km East of Bribri (09°37’50”N; 82°49’06”W), 11.vi.2001, 1L, DEB ; unnamed creek at Hwy 32, ca. 3 Km W of Pocora (10°10’38”N; 83°37’03”W), 10.vi.2001, 2L, DEB ; unnamed stream at road, ca. 2 Km NW Puerto Viejo (09°38’43”N; 82°47’12”W), 11.vi.2001, 1L, DEB . Puntarenas Prov.: 1 Km S Coloradito, Río Coloradito at Hwy. 2 (08°36’10”N; 82°54’07”W), 17.vi.2000, 3L, WDS ; 4.1 Km N Dominical on Hwy. 243, unnamed river (09°16’51”N; 83°50’55”W), 14.vi.2000, 2L, WDS ; Río Jaba at Las Cruces Biological Station, ca. 14 Km. S San Vito, 23, 24.vi.2001, 1L, 1♂ (reared), DEB ; Estacion Biologica Monteverde, Quebrada Moquina (10°19’N; 84°48’W), 24.i.2000, 2L, WDS ; Río Baru at Baru, ca. 5 Km NE Dominical, 22.vi.2001, 1L, DEB ; 1 Km S Coloradito, Río Coloradito at Hwy 2 (08°36’10”N; 82°54’07”W), 17.vi.2000, 6L, WDS ; Quebrada Culebra at Las Cruses Biological Station, ca. 14 Km S. San Vito, 24.vi.2001, 2L, DEB ; NE Dominical, unnamed stream (09°16’48”N; 83°49’22”W), 19.vi.2000, 1L, WDS ; unnamed creek at Hwy. 34, ca 37.5 Km SE Dominical (09°03’04”N; 83°37’00”W), 22.vi.2001, 5L, DEB ; Río Caracol at CA Hwy. 2, ca. 7.3 Km E. Río Claro (08°39’47”N; 83°00’41”W), 23.vi.2001, 3L, DEB ; 5 Km SE Coloradito, unnamed river (08°34’41”N; 82°52’28”W), 17.vi.2000, 1L, WDS . San Jose Prov.: Río Pedregoso at Hwy. 243, ca. 4 Km S. San Isidro de El General (09°21’15”N; 83°43’35”W), 22.vi.2001, 1L, DEB . GUATEMALA: Chiquimula Dept.: Río Anguiatu, Frontera a Anquiata, 13.vii.1995, 1L, Bryan Yates; El Progreso Dept.: Río Hato at CA Hwy. 9, ca. 5.9 Km E. from jct. with Hwy. 17, Magdalena (14°55’11”N; 89°57’56’W), 14.vii.2001, 3L, DEB ; Quebrada Las Pericas at Hwy. 17, 11.1 Km W. from jct. with Hwy. CA (09°14’54”N; 90°05’52”W) , 12.vii.2001, 4L, DEB ; Izabel Dept.: Río Cienega at CA Hwy. 13, ca. 4 Km. S. Shaila (15°43’53”N; 89°84’44”W), 16.vii.2001, 1L, DEB ; Zacapa Dept.: Río Cayo at CA Hwy. 9, 2.3 Km E. Santa Cruz (15°00’54”N; 89°39’09’W), 14.vii.2001, 1L, DEB ; Río Cayo at CA Hwy. 9, 2.3 Km E. Santa Cruz (15°00’54’N; 89°39’09’W), 14.vii.2001, 3L, DEB . MEXICO: Nuevo Leon: Río Cabazones at Hwy. 85, 15 mi. N. Linares., 5L, 16.v.1995; unnamed creek at road leading to Brownsville, nr. town of Galenana off Hwy. 60, 9L, 19.v.1995; Queretaro: Puerta de Alegriax , Arroyo Los Zunigas (20°20’28”N; 100°07’10”W), 1L, 08­vii­2000, WDS ; 1 Km. S. Huasquilico, Arroyo Jalpan (21°09’04”N; 99°34’42”W), 7L, 11.vii.2000, WDS ; 1 km SSE San Pedro, Arroyo Real (21°07’07”N; 99°32’05”W), 12L, 11.vii.2000, WDS ; Chuveje, Río Chuveje (21°10’13”N; 99°33’18”W), 12.vii.2000, 1L, WDS ; Pínal de Amoles , Agua Fria ( UTM 2338413 ), 1L, 28.viii.1997, R . Jones; San Luís Potosi: Río Moctezuma at Tamazunchale on Hwy. 85, 2L, 18.viii.1977, R . K. Allen ( CAS); Tamaulipas: Río San Marcos nr. Ciudad Victoria, 14L, 24/ 25.x.1968, R . K. Allen ( CAS); Branch of Río Chihue at Hwy. 101, ca. 12 mi. S Juamave, nr. kilo. marker #91, 10L, 17.v.1995, DEB . NICARAGUA: Granada: Unnamed river at Domitila Field Station , ca. 30 km S Granada (N11º42'09"; W85º57'06”), 13­18.vi.2004, 68L, 2♂ (reared, 1 slide, #DB05012901 – genitalia drawn from this slide), 7♀ (reared), DEB .