Larval morphology of Liodessus Guignot, 1939: generic characteristics,  descriptions of five species and comparisons with other members of the tribe Bidessini (Coleoptera: Dytiscidae: Hydroporinae)

Zootaxa ◽  
2007 ◽  
Vol 1516 (1) ◽  
pp. 1-21 ◽  
Author(s):  
YVES ALARIE ◽  
MARIANO C. MICHAT ◽  
MIGUEL ARCHANGELSKY ◽  
HELEN M. BARBER-JAMES

The larvae of Liodessus affinis (Say, 1823), L. crotchi Nilsson, 2001, L. flavofasciatus (Steinheil, 1869), L. involucer (Brinck, 1948), and L. patagonicus (Zimmermann, 1923) are described with an emphasis on chaetotaxy of the head capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of these species are very uniform in terms of larval morphology. Considering all known bidessine larvae, Liodessus Guignot, 1939 is more similar to Hypodessus Guignot 1939, Amarodytes Régimbart, 1900, Anodocheilus Babington, 1841, Glareadessus Wewalka & Biström, 1998, Allodessus Guignot, 1953, and Neoclypeodytes Young, 1967, all these genera sharing a short siphon and an elongate first urogomphomere. Liodessus differs from Hypodessus, Amarodytes and Anodocheilus by absence of the primary pore PAj whereas it shares with Anodocheilus the absence of a ventroapical spinula on the third antennomere.

1988 ◽  
Vol 19 (3) ◽  
pp. 381-391 ◽  
Author(s):  
Anders N. Nilsson

AbstractA lectotype is designated for Agabus setulosus (J. Sahlberg, 1895), a rare rheophilous dytiscid known mainly from northern Fennoscandia. The larval instars are described for the first time, based on material from northern Sweden. The first-instar larva is characterized by the presence of two dorsal spines on each femur and a pair of mediodorsal setae on last abdominal segment; both characters are seemingly unique among Agabus. The third instar differs from all other Palaearctic Agabus species in the complete sclerotization of the ring-like abdominal segment 6. The biology of A. setulosus is described from a Swedish population; semivoltine life cycle with overwintering eggs laid in summer followed by adult overwintering prior to breeding is suggested.


2009 ◽  
Vol 40 (2) ◽  
pp. 209-228 ◽  
Author(s):  
Miguel Archangelsky ◽  
Mariano Michat

AbstractThe phylogenetic relationships of the diving beetle (Dytiscidae) genus Leuronectes Sharp are revised based on a cladistic analysis of seven Agabinae genera and 54 morphological and chaetotaxic characters from larvae. For this purpose, larvae of L. curtulus Régimbart are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy. The results show that Leuronectes is well placed within Agabinae based on the absence of natatory setae on tibia and tarsus in instars II and III, the urogomphus composed of two urogomphomeres, and the absence of secondary setae on urogomphus. Leuronectes is resolved as part of a basal polytomy along with Platynectes Régimbart and a clade formed by the remaining agabine genera. Leuronectes shares with Platynectes the setae UR2, UR3 and UR4 not inserted contiguously, with Platambus Thomson the anterolateral lobes of frontoclypeus not projected beyond anterior margin, with Hydrotrupes Sharp the seta AB9 inserted dorsolaterally, and with Ilybius Erichson the seta LA10 inserted submedially. Leuronectes is unique within Agabinae in having the apical lateroventral process of the third antennomere not protruding and additional ventroapical pores on third antennomere, and is unique within the dytiscid genera studied in having the seta LA12 inserted submedially and one additional spine-like seta inserted on the lateral margin of abdominal segment VIII.


2005 ◽  
Vol 36 (2) ◽  
pp. 183-198 ◽  
Author(s):  
Eduardo Galante ◽  
Estefanía Micó

AbstractThe third instar larvae of five anomaline species, Anomala dubia (Scopoli, 1763), Anomala quadripunctata (Olivier, 1789), Blitopertha lineata (Fabricius, 1798), Mimela rugatipennis (Graells, 1849) and Phyllopertha horticola (Linnaeus, 1758) are described as well as their biological data. The analysis of the morphology of the four distinct genera studied revealed diagnostic differences in leg morphology, last abdominal segment, and spiracles. An approach to the phylogeny of the group based on larval characteristics is provided. Finally, the systematic position of Blitopertha Reitter, 1903 is discussed.


1991 ◽  
Vol 123 (3) ◽  
pp. 627-704 ◽  
Author(s):  
Y. Alarie

AbstractThe larvae of 17 species of Hydroporus Clairville were described and characterized; a key for their discrimination and illustrations of structural features of first- and third-instar larvae are provided. Many structural features, especially those of chaetotaxy and porotaxy of head capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for taxonomic and phylogenetic comparisons. Based on 21 larval characters, the phylogenetic relationships among the five main lineages of Hydroporus (s. lat.) occurring in North America were studied. Structurally, the species of the subgenus Hydroporus (s. str.) and of the vilis species-group (H. planiusculus Fall) were found to be the most generalized taxa whereas the subgenera Neoporus Guignot and Heterosternuta Strand encompassed the species with the most derived condition. The subgenus Heterosternuta was closely related to the subgenus Neoporus and both subgenera were hypothesized to form a distinct monophyletic unit on the basis of five synapomorphies. The only representative of the oblitus species-group studied, H. paugus Fall, was related to Hydroporus (s. str.) and the vilis species-group by the shape of the siphon. This species was a very peculiar clement within Hydroporus (s. lat.) because it was the only known species of the genus without stemmaia in the first- and second-instar larvae, with stemmata greatly reduced in size in the third-instar larvae, and with a secondary dorsomedian seta on antennomere 2. The larval features of Hydroporus (s. lat.) were compared with those of Hygrotus Stephens. The comparison suggested that both genera form a monophyletic unit, that each of them is a distinct monophyletic unit, and that Hydroporus (s. lat.) is the sister-group of Hygrotus Stephens.


ZooKeys ◽  
2019 ◽  
Vol 884 ◽  
pp. 53-67
Author(s):  
Mariano C. Michat ◽  
Yves Alarie ◽  
Chris H. S. Watts

In this contribution, the larval morphology of Spencerhydrus Sharp, 1882 was studied, an Australian endemic genus in the diving beetle tribe Cybistrini. All instars of the only two species included in the genus (S. latecinctus Sharp, 1882 and S. pulchellus Sharp, 1882) are described and illustrated with the exception of the third instar of S. latecinctus. Detailed morphometric and primary chaetotaxic analyses were performed to discover useful characters for generic diagnosis and species distinction. Spencerhydrus can be distinguished from other Cybistrini genera by the medial projection of frontoclypeus slightly indented apically, with lamellae clypeales directed forward in a characteristic V-shaped pattern, the median process of prementum strongly developed, the presence of a single ventral sclerite on prothorax, the presence of basoventral spinulae on claws, and the reduced sclerotization of the abdominal segment VII which covers only the anterior half. Larvae of the two species of Spencerhydrus can readily be distinguished by the shape of the median process of prementum, which is visibly broader in S. pulchellus than in S. latecinctus.


Zootaxa ◽  
2020 ◽  
Vol 4718 (3) ◽  
pp. 436-446
Author(s):  
EDWARD TSYRLIN ◽  
MELISSA CAREW ◽  
YVES ALARIE

The second and third larval instars of the Australian endemic dytiscid Chostonectes nebulosus (Macleay, 1871) are described and illustrated for the first time including a detailed chaetotaxic analysis of head capsule and appendages, legs, last abdominal segment and urogomphi. Collected larvae were successfully associated with adults using rearing and a molecular approach. The identification key and COI barcodes for C. nebulosus, C. gigas (Boheman, 1858) and C. johnsonii (Clark, 1862) are provided. 


2006 ◽  
Vol 85 (1) ◽  
pp. 307 ◽  
Author(s):  
Yves Alarie ◽  
Samantha Hughes

New descriptions of the larvae of <em>Meladema lanio</em> (Fabricius), <em>M</em>. <em>coriacea</em> Laporte and <em>Hoperius planatus </em>Fall are provided. Characters from larval morphology are analyzed to infer the phylogenetic relationships of the genera <em>Meladema</em> Laporte and <em>Hoperius</em> Fall with other genera of the tribe Colymbetini (Colymbetinae). Larvae of <em>Meladema</em> are unique among other Colymbetini being characterized by the presence of a variable number of additional setae along the dorsal margin of both femora and tibiae. Larvae of <em>Hoperius</em> reveal to be remarkably modified and autapomorphic being characterized by a short antennomere II, the presence of a variable number of secondary setae on antennomeres I - II and maxillary palpomere, an elongate maxillary palpus, and a narrow and elongate mandible. A parsimony analysis based on 30 informative larval characters is carried out. Whereas the 12 most parsimonious trees support the placement of <em>Meladema</em> as sister to <em>Neoscutopterus</em> J. Balfour-Browne, the relative position of Hoperius remains unresolved within the Colymbetini. Larvae of <em>Meladema</em> share with those of <em>Neoscutopterus</em>: (i) the presence of additional setae both on the frontoclypeus and parietale, (ii) the presence of a large number of secondary setae on trochantera, (iii) the absence of spinulae along ventral margin of mesotibia and mesotarsus and (iv) the presence of additional setae both on abdominal segment VIII.


Zootaxa ◽  
2019 ◽  
Vol 4619 (1) ◽  
pp. 121-138 ◽  
Author(s):  
JUAN I. URCOLA ◽  
YVES ALARIE ◽  
CESAR J. BENETTI ◽  
GEORGINA RODRIGUEZ ◽  
MARIANO C. MICHAT

The three larval instars of Suphis cimicoides Aubé, 1837 are described and illustrated, including morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphus. A preliminary ground plan of primary chaetotaxy for noterid larvae is presented for the first time, based on the species described herein and examination of larvae of the genera Hydrocanthus Say, 1823 and Suphisellus Crotch, 1873. This ground plan is compared with previous systems proposed for other adephagan families. Larvae of Noteridae can be distinguished from those of other families of Hydradephaga by the following combination of characters: (1) antennomere 3 with a rugged area on distal portion; (2) abdominal segment VIII with a U-shaped wavy membranous area ventrally; (3) absence of pore FRd; and (4) presence of seta AB16. Several sensilla present in noterid larvae (notably setae TR2 and TA1 and pores PAl, PAm, COd, TRb and FEb) are absent in larvae of Meruidae. On the contrary, parietal seta PA5 is present in Meruidae but absent in Noteridae. The presence of pore COc in Noteridae may indicate that this family has retained the ancestral condition found only in Carabidae. On the other hand, the absence of setae FE7, FE8, FE9 and FE10 in Noteridae is similar to the condition found in Carabidae, Gyrinidae and Meruidae. 


1968 ◽  
Vol 100 (2) ◽  
pp. 202-206 ◽  
Author(s):  
Louis F. Wilson

AbstractThe willow beaked gall midge, Mayetiola rigidae (Osten Sacken), is univoltine in Michigan. Adults emerge from bud galls on Salix discolor Mühl. and other willows on mornings of warm days in early April. Eggs are laid singly on or near the buds of the host. Head capsule measurements indicate three larval instars. The last two instars each possess a spatula. The first-instar larva emerges in late April and penetrates the soft bud tissues. The gall begins to develop at the beginning of the second instar in mid-May. The third instar appears in early July and continues to enlarge the gall until fall. Prior to overwintering, the larva lines the inner chamber of the gall with silk and constructs one to seven silken septa across the passageway. Pupation occurs in mid-March. The gall deforms the stem and occasionally a galled branch dies or breaks off.


1990 ◽  
Vol 122 (5) ◽  
pp. 985-1035 ◽  
Author(s):  
Y. Alarie ◽  
P.P. Harper ◽  
R.E. Roughley

AbstractA systematic analysis of larvae of 11 Nearctic species of Hygrotus Stephens was undertaken. The larvae are described and characterized; a key for their discrimination and illustrations of structural features of representatives of first- and third-instar larvae are provided. Many structural features, especially detailed variations in the chaetotaxy of cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for systematic and phylogenetic comparisons. Based on 21 larval characters, a cladistic analysis of the species studied was developed. A sister-group relationship between H. laccophilinus (LeConte) and the remaining available species is suggested. The less derived species, i.e. those without natatory setae on the legs, appear phylogenetically more closely related to the larvae of Hydroporus s.str. Hygrotus masculinus (Crotch) is the most derived species of the genus and, for many characters, seems more closely related to Hyphydrini. According to larval morphology, it is hypothesized that the genus Hygrotus diverged posteriorly to the genus Hydroporus Clairville.


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