Alainites siamensis, Phlai-ngam & Tungpairojwong & Gattolliat, 2022

Phlai-ngam, Sirikamon, Tungpairojwong, Nisarat & Gattolliat, Jean-Luc, 2022, A new species of Alainites (Ephemeroptera, Baetidae) from Thailand, Alpine Entomology 6, pp. 133-146 : 133

publication ID	https://dx.doi.org/10.3897/alpento.6.96284
publication LSID	lsid:zoobank.org:pub:5E5F0159-E775-4AF5-A92F-18A1F6F4A75E
persistent identifier	https://treatment.plazi.org/id/DF090CF3-0863-4454-A90B-EB58DFB6D49D
taxon LSID	lsid:zoobank.org:act:DF090CF3-0863-4454-A90B-EB58DFB6D49D
treatment provided by	Alpine Entomology by Pensoft
scientific name	Alainites siamensis
status	sp. nov.

Treatment

Alainites siamensis sp. nov.

Material.

Holotype: Thailand • Larva; Phetchabun Province, Nam Nao National Park, Yakruae stream; Alt. 832 m. 16°44'27.92"N, 101°34'46.52"E; 7 Mar. 2022; Coll. S. Phlai-ngam and V. Vannachak; 1L on slide GBIFCH00763744 [MZL]. GoogleMaps

Paratypes: Thailand • 20 larvae; same data as holotype; 3L on slides GBIFCH00763745-GBIFCH00763747, [MZL]; 10L in alcohol GBIFCH00763748 [MZL]; 7L in alcohol [KKU-AIC] GoogleMaps .

Other material.

Thailand • 70 larvae; Tak Province, Mae Ra Mad District; Alt. 405 m . 17°04'52.68"N, 098°45'16.76"E; 12 Feb. 2022; Coll. K. Koomput and P. Dapsibhai; 1L on slides GBIFCH00763749 [MZL]; 8L in alcohol GBIFCH00763750 [MZL]; 10L in alcohol [KKU-AIC]. Tak Province, Mae Sod District, small stream near the road (unnamed stream); Alt. 719 m . 17°01'44.35"N, 098°30'24.47"E; 8 Oct. 2020; coll. S. Phlai-ngam; 1L on slide [KKU-AIC]; 14L in alcohol [KKU-AIC]; 1L in alcohol GBIFCH 00673245 [MZL]. Kanchanaburi Province, Thong Pha Phumi District, small stream near the Mining Dr. Phol Kleepbuathe; Alt. 660 m . 14°45'08.00"N, 98°48'40.00"E; 16 Nov. 2022; Coll. S. Phlai-ngam; 1L on slide GBIFCH00763751 [MZL]; 7L in alcohol GBIFCH00763752 [MZL], 8L in alcohol [KKU-AIC]. Phetchabun Province, Nam Nao National Park, Yakruae stream; Alt. 832 m . 16°44'27.92"N, 101°34'46.52"E; 23 Nov. 2020; Coll. S. Phlai-ngam; 15L in alcohol [KKU-AIC]. Kamphaengphet Province, Klong Lan District, Pong Nam Ron, Alt. 154 m. GoogleMaps GoogleMaps GoogleMaps GoogleMaps 17°02'34.94"N, 98°58'39.83"E; 12 Feb. 2022; Coll. K. Koomput and P. Dapsibhai; 4L in alcohol [KKU-AIC].

Description.

Coloration (Figs 1 View Figure 1 , 2 View Figure 2 ). General coloration medium brown. Head uniformly medium brown, slightly darker between ocelli and at insertion of antennae. Turbinate eyes in male larva dark orange. Thorax medium brown with indistinct pattern. Pronotum slightly paler than mesonotum and metanotum. Thoracic sternites mostly pale brown. Abdominal tergites medium brown, slightly darker in middle area, distal margin with darker transverse band. Abdominal sternites light brown. Cerci and median caudal filament light brown without bands or pattern.

Body. Maximum length 4.2 mm. Median caudal filament ca. 2/3 of cerci.

Head. Capsule medium brown. Antennae medium brown, filiform.

Mouthparts. Labrum (Fig. 3A View Figure 3 ): dorsal surface with one central seta and an arc of setae reduced to two lateral setae; about twenty fine stout setae scattered over surface. Ventral surface with five small acute setae near lateral margin. Distal margin fringed with two kinds of setae: long lateral setae strongly feather-like and medially with a shorter row of slightly feather-like setae.

Left mandible (Fig. 3B-D View Figure 3 ): inner and outer incisors almost fused, formed by seven blunt denticles (Fig. 3C View Figure 3 ); prostheca with eleven small pointed denticles apically, (Fig. 3D View Figure 3 ); edge between prostheca and mola only slightly crenelate near mola; mola with an enlarged triangular pointed tooth, fine setae present apically; proximal part with scattered fine setae, not shagreened (Fig. 3B View Figure 3 ). Right mandible (Fig. 3E-G View Figure 3 ): inner and outer incisors almost fused, formed by eight blunt denticles (Fig. 3F View Figure 3 ), prostheca bifid, both filaments feathered, outer filament half length inner filament (Fig. 3G View Figure 3 ); edge between prostheca and mola crenelate; proximal part with scattered fine setae, not shagreened (Fig. 3E View Figure 3 ). Maxilla (Fig. 3H-I View Figure 3 ): galea-lacinia with 3 enlarged acute teeth on apex (Fig. 3I View Figure 3 ), 2 rows of long dense basal setae on galea-lacinia; maxillary palpus (Fig. 3H View Figure 3 ) 2-segmented with scattered small hair-like setae; segment II rounded at apex. Labium (Fig. 3J View Figure 3 ): glossa slightly shorter than paraglossa; a row of stout setae along outer, inner and apical margins, subapical setal tuft present; paraglossae with 3 rows of simple setae along apical margin; labial palpus 3-segmented with scattered fine setae; segment I slightly shorter than segments II and III combined; segment III subrectangular covered with long robust setae mostly in distal half, short pointed setae mostly along outer margin and abundant fine setae. Hypopharynx with rounded lingua and superlinguae, covered with abundant hair-like setae subapically (Fig. 3K View Figure 3 ).

Thorax. Hindwing pads well developed.

Foreleg (Fig. 4A View Figure 4 ). Femur: dorsal margin with a regular row of eight to eleven long robust setae and two subapical setae; ventral margin with abundant short spine-like setae; lateral margin with scale bases, bare and not shagreened, femoral villopore absent.

Tibia (Fig. 4B View Figure 4 ): dorsal margin of fore-tibia with less than five strong setae (usually with 3-4 setae), short fine setae roughly arranged in row; ventral margin with abundant short stout setae ending with patch of long stout feathered setae; lateral margin with abundant scale bases, tibiopatellar suture with short spine-like setae. Tarsus: dorsal margin with few fine setae, ventral margin with abundant pointed setae only slightly increasing in length toward apex, lateral margin with abundant scale bases and a few fine setae. Tarsal claws (Fig. 4E View Figure 4 ) with one row of 7-9 denticles, increasing in size distally, subapical setae absent. Midleg and hindleg. Similar to foreleg; except ventral margin of femur of hindleg with reduced number of short spine-like setae, generally one or two setae; dorsal margin of mid- tibia (Fig. 4C View Figure 4 ) and hind-tibia (Fig. 4D View Figure 4 ) with more than five strong setae (usually more than nine).

Abdomen. Posterior margin of tergite I smooth; posterior margin of tergite II with a few triangular spines mainly in the middle area; posterior margin of tergites III-IX with triangular spines along central portion, absent laterally (Fig. 4F-G View Figure 4 ). Surface of all tergites not shagreened, with numerous scale bases and few setae. Sternites I-VIII similar to tergites except distal margin smooth, sternite IX distal margin with triangular spines. Gills (Fig. 5A-D View Figure 5 ) on segments I-VII, with well visible main tracheation but reduced ramification; gill I smallest (Fig. 5A View Figure 5 ), length of gill I equal to half of tergite II; gill IV (Fig. 5B View Figure 5 ) and gill V larger than others, length of gill IV equal to tergite V plus half of tergite VI; length of gill V equal to tergite VI plus half of tergite VII; length of gill VII (Fig. 5D View Figure 5 ) equal to tergite VIII plus half of tergite IX. Surface smooth without any setae or pores, margin serrated with fine simple setae (Fig. 5C View Figure 5 ). Paraproct (Fig. 5E-F View Figure 5 ) covered with scale bases and micropores on surface; distal margin with well-developed prolongation; lateral margins of prolongation with numerous small spines, surface without spines (Fig. 5F View Figure 5 ); distal margin inner to prolongation with 5 huge spines, distal margin outer to prolongation with numerous medium spines (around 20-30 spines); cercotractor with scale bases, distal margin with about 14-16 medium spines (Fig. 5E View Figure 5 ). Cerci with fine swimming setae along inner margin. Median filament with swimming setae on both margins.

Diagnosis.

Alainites siamensis sp. nov. is closely related to A. lingulatus , A. laetificus and A. yixiani ; these species are distributed in the Southeast Asia. The new species can be separated from the other species by the following combination of characters: i) the shape of labial palp, ii) the setation on tibia, iii) the number of denticles of the claws, iv) the degree of development and spination of paraproct prolongation, v) the number of spines on distal margin of paraproct, vi) number of pairs of gills (Table 4 View Table 4 ).

Ecological notes.

The larvae of Alainites siamensis sp. nov. mainly live among aquatic plants and roots of riparian plants in slow to moderately flowing streams (Fig. 6 View Figure 6 ). The species seems to be rather widely distributed in the northwestern and northern Thailand, but is rare and not abundant (Fig. 7 View Figure 7 ).

Etymology.

The specific epithet of this species, siam (noun), refers to the old name of Thailand and to the known distribution of the species.

Molecular result.

Sequences of 658 bp, corresponding to a fragment of the COI gene, were obtained from six specimens collected in three localities; the new sequences are deposited in GenBank under accession numbers specified in Table 2 View Table 2 . The K2P analysis for genetic distances analysis shows that the three populations of Alainites siamensis sp. nov. have very low intraspecific variation (0% to <2%). The interspecific distances between A. siamensis sp. nov. and other Alainites species show distances between 17% and 28% (Table 3 View Table 3 ). In the COI reconstruction, the six larval specimens of Alainites from Thailand were grouped together into the same clade and clearly separated from all other sequenced species of Alainites (Fig. 9 View Figure 9 ).