Larval morphology of the tribe Matini (Coleoptera: Dytiscidae, Colymbetinae): descriptions of Batrachomatus daemeli, Matus bicarinatus, and Allomatus nannup and phylogenetic relationships

2001 ◽  
Vol 133 (2) ◽  
pp. 165-196 ◽  
Author(s):  
Yves Alarie ◽  
Chris H.S. Watts ◽  
Anders N. Nilsson

AbstractDescriptions are presented of larval instars of three species of the colymbetine tribe Matini Zimmermann (Coleoptera: Dytiscidae), Batrachomatus daemeli (Sharp), Matus bicarinatus (Say), and Allomatus nannup Watts, including a chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. A parsimony analysis based on 32 informative larval characteristics was conducted with the computer program NONA. Members of the Matini are postulated to share a monophyletic origin based on (i) seta TR2 articulated anteroventroproximally on the trochanter; (ii) seta TR5 elongate on the metatrochanter; (iii) seta TA1 elongate and inserted proximally on the tarsus; (iv) antenomere III with a hole-like ventroapical spinula; (v) prementum with the primary setae LA2, LA3, LA4, LA5, and LA8 spine-like and elongate; (vi) presence of secondary setae on the cephalic appendages; and (vii) presence of additional primary setae on the last abdominal segment. A clade Matini + Colymbetini is postulated based on (i) metafemoral seta FE5; (ii) metafemoral seta FE6; (iii) seta TI6 on tibia, all elongate and hair-like; (iv) one-segmented urogomphus; (v) presence of an occipital suture in first instar; (vi) galea elongate; (vii) presence of natatory setae on legs; and (viii) presence of secondary setae on the urogomphus.

2000 ◽  
Vol 31 (2) ◽  
pp. 121-164 ◽  
Author(s):  
Chris H.S. Watts ◽  
Anders N. Nilsson ◽  
Michael Balke ◽  
Lars Hendrich ◽  
Yves Alarie

AbstractDescriptions of the larval instars of four genera (12 species) of the dytiscid subfamily Laccophilinae, Laccophilus Leach, Neptosternus Sharp, Australphilus Watts and Africophilus Guignot, are presented including a detailed chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysis, based on the 13 informative larval characteristics was conducted with Hennig86. The genus Africophilus is postulated to represent the sister-group of a clade comprised of Laccophilus + (Neptosternus + Australphilus) which is supported by, (i) primary seta CO7 articulated proximally on all legs, (ii) presence of natatory setae, (iii) metatibia + metatarsus very elongated, and (iv) elongated urogomphi.


1999 ◽  
Vol 30 (2) ◽  
pp. 173-195 ◽  
Author(s):  
Lars Hendrich ◽  
Yves Alarie ◽  
Anders N. Nilsson

AbstractDescription of larval instars of Deronectes depressicollis Rosenhauer 1856, D. lareynii (Fair-maire 1858), D. latus (Stephens 1829), D. aubei (Mulsant 1843), and Scarodytes halensis (Fabricius 1787) is presented including a detailed chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal scgment and urogomphi. A phylogenetic analysis of 14 genera of the tribe Hydroporini, based on 22 larval characteristics was conducted with Hennig86. Three of the branches of the strict consensus tree have a statistical support greater than 60% according to the Parsimony Jackknifer. One of the supported clades is Antiporus Sharp + Nebrioporus Régimbart + Neonectes J. Balfour-Browne + Oreodytes Seidlitz + Stictotarsus Zimmermann + Scarodytes Gozis, of which the sister-group is the genus Deronectes Sharp. Consequently larval characters, in contrast to adult characters support the inclusion of Antiporus, Neonectes and Oreodytes in the Deronectes-group of genera. All members of this clade are characterized by: (i) presence of an occipital suture in first instar, (ii) presence of a constriction at level of occipital suture, (iii) absence of maxillary cardo, and (iv) insertion of the primary seta MX I on the maxillary stipes. Scarodytes is postulated to share a monophyletic origin with Nebrioporus, Stictotarsus, and Antiporus based on (i) the presence of natatory setae on femora, tibiae, and tarsi and (ii) the shape of the urogomphomere I which is more than 3.10 times longer than urogomphomere 2.


Zootaxa ◽  
2009 ◽  
Vol 2317 (1) ◽  
pp. 1-102 ◽  
Author(s):  
YVES ALARIE ◽  
MARIANO C. MICHAT ◽  
ANDERS N. NILSSON ◽  
MIGUEL ARCHANGELSKY ◽  
LARS HENDRICH

Descriptions of larval instars of 22 species of Rhantus Dejean, 1833 are presented including a detailed chaetotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysis including 25 Rhantus species (the 22 species described in this paper + 3 additional ones) from all major zoogeographic regions and representatives of other Colymbetini genera was conducted using the program TNT based on 43 informative larval characteristics. Jackknife values indicate strong support for the monophyly of members of the tribe Colymbetini (Colymbetinae), which is supported by eight synapomorphies. It is postulated that Rhantus is polyphyletic as Rhantus (Nartus) grapii (Gyllenhal, 1908) and R. monteithi Balke, Wewalka, Alarie & Ribera, 2007 occur as more closely related phylogenetically to other genera of the tribe Colymbetini than to the Rhantus species studied. We suggest that the Neotropical species R. orbignyi Balke, 1992, R. antarcticus nahueli Trémouilles, 1984, R. calidus (Fabricius, 1792) and R. validus Sharp, 1882 represent a distinct lineage within the Colymbetini. All these species diverge at the basis of the strict consensus trees prior to all other Colymbetini studied and are characterized by several unique larval character states. Larvae of Palearctic and Nearctic species of Rhantus were found to share similar character states, which is suggestive of a common phylogenetic origin.


Zootaxa ◽  
2008 ◽  
Vol 1922 (1) ◽  
pp. 47-61 ◽  
Author(s):  
MARIANO C. MICHAT

The larvae of three Neotropical species of the diving beetle genus Laccophilus Leach (Laccophilus obliquatus Régimbart, L. paraguensis Régimbart and L. testudo Régimbart) are described and illustrated for the first time, with an emphasis on morphometry and chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of these species lack the primary setae LA10 and LA12, and have the primary seta CO7 articulated proximally on all coxae, two apomorphies that define the subfamily Laccophilinae. They are also characterized by a frontoclypeus truncate proximally in the first instar, the presence of pectens on legs, and the presence of secondary setae on first urogomphomere. These character states are apomorphies that define the genus Laccophilus Leach. The absence of pore PAc and the presence of a dense group of secondary spiniform setae dorsally at the base of the siphon in instar III may also characterize this genus, as similar states are not found in other dytiscids. On the other hand, L. obliquatus, L. paraguensis and L. testudo differ from the other species of Laccophilus known in detail in the presence of an additional seta on the stipes and in the absence of pore ABc. Brief comments on the putative phylogenetic relationships of Laccophilinae and Laccophilus inferred from larval morphology, as well as on the characters potentially useful in studying relationships within the group are presented.


2013 ◽  
Vol 145 (3) ◽  
pp. 247-264 ◽  
Author(s):  
Mariano C. Michat ◽  
Yves Alarie

AbstractLarval morphology of the monogeneric subfamily Coptotominae (Coleoptera: Dytiscidae) is described and illustrated in detail, with particular emphasis on morphometry and chaetotaxy. Larvae ofCoptotomusSay are unique within Dytiscidae in the presence of tracheal gills on the abdominal segments I–VI, a short bifid horn or nasale in instar I, long spinulae on the urogomphus in instar I, and rows of natatory setae on both the internal and external margins of the urogomphus in instars II and III. A cladistic analysis based on 125 larval characters sampled among representatives of other dytiscid subfamilies supports a sister-group relationship between Coptotominae and Laccophilinae based on the shared absence of setae LA10 and LA12 on the second labial palpomere and of pore ABc on the abdominal segment VIII. The clade Coptotominae + Laccophilinae resolved as sister to Lancetinae, all three subfamilies sharing the presence of an unusually low number of lamellae clypeales in the first instar (a condition called four-peg-pattern), postulated to have evolved secondarily within Dytiscidae.


1995 ◽  
Vol 127 (6) ◽  
pp. 913-943 ◽  
Author(s):  
Yves Alarie

AbstractThrough an analysis of the primary setae and pores (campaniform sensilla) of first-instar larvae of 32 species of Colymbetinae, 33 species belonging to other dytiscid subfamilies, and seven species belonging to other families of Hydradephaga, the ancestral system of primary setae and pores of the legs, the last abdominal segment, and the urogomphi of Colymbetinae is deduced. Seventy-four setae and 24 pores have been assigned to the generalized colymbetine larva: 51 setae and 18 pores on the legs, 15 setae and three pores on the last abdominal segment, and eight setae and three pores on each urogomphus. A comparison with the ground-plan pattern of the subfamily Hydroporinae is provided. Members of Colymbetinae differ from those of Hydroporinae by the presence of setae TR3, AB14, and AB15, the absence of pore ABd, and the presence of a variable number of additional setae on the femur. A tentative phylogenetic reconstruction of the colymbetine genera provided is based on 24 larval characteristics. The monophyletic origin of the subfamily Colymbetinae is confirmed based on the shared presence of seta AB14. Two monophyletic lineages unite basally: (1) [(Agabus Leach + Ilybius Erichson) + Agabinus Crotch], and (2) {[Colymbetes Clairville + (Rhantus Dejean + Neoscutopterus Balfour-Browne)] + Matus Aubé}. The genera Agabinus and Matus are postulated as a sister-group of (Agabus + Ilybius) and [(Colymbetes + (Rhantus + Neoscutopterus)], respectively. Compared with other Colymbetinae, both Neoscutopterus and Matus stand out by the presence of several strikingly peculiar features. The subgenus Rhantus (Nartus) is postulated to be the sister-group of Neoscutopterus based on the shared presence of additional setae on the dorsal margin of the femur.


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. 


Zootaxa ◽  
2012 ◽  
Vol 3584 (1) ◽  
pp. 1 ◽  
Author(s):  
MARIANO C. MICHAT ◽  
YVES ALARIE ◽  
CHRIS H. S. WATTS

The larvae of five epigean and 25 stygobitic species of the diving beetle genus Limbodessus Guignot, 1939 are describedand illustrated for the first time, with special emphasis on morphometry and chaetotaxy of the cephalic capsule, headappendages, legs, last abdominal segment and urogomphi. Those of the following five epigean species are described: L.amabilis (Clark, 1862), L. compactus (Clark, 1862), L. inornatus (Sharp, 1882), L. praelargus (Lea, 1899), L. shuckardii(Clark, 1862). The 25 stygobitic larvae described are: L. barwidgeeensis Watts & Humphreys, 2006, L. bigbellensis(Watts & Humphreys, 2000), L. challaensis (Watts & Humphreys, 2001), L. cooperi Watts & Humphreys, 2006, L.eberhardi (Watts & Humphreys, 1999), L. exilis Watts & Humphreys, 2006, L. fridaywellensis (Watts & Humphreys,2001), L. hillviewensis (Watts & Humphreys, 2004), L. hinkleri (Watts & Humphreys, 2000), L. leysi Watts & Humphreys,2006, L. macrohinkleri Watts & Humphreys, 2006, L. masonensis (Watts & Humphreys, 2001), L. millbilliensis Watts &Humphreys, 2006, L. mirandaae Watts & Humphreys, 2006, L. morgani (Watts & Humphreys, 2000), L. nambiensisWatts & Humphreys, 2006, L. ordinarius Watts & Humphreys, 2009, L. palmulaoides Watts & Humphreys, 2006, L.pulpa (Watts & Humphreys, 1999), L. raeae Watts & Humphreys, 2006, L. raesideensis (Watts & Humphreys, 2001), L.windarraensis (Watts & Humphreys, 1999), L. yandalensis Watts & Humphreys, 2006, L. yarrabubbaensis Watts & Humphreys, 2009, L. yuinmeryensis (Watts & Humphreys, 2003). The morphology and chaetotaxy of epigean vs.stygobitic species are compared, and a key for the identification of the species is presented. Contrary to their epigeancounterparts, larvae of stygobitic Limbodessus have turned out to be very divergent morphologically. In addition to thecommon characteristics associated with an underground living (i.e., absence of stemmata, reduced pigmentation, and thinor soft exoskeleton), larvae of these species have undergone a variable modification of the frontoclypeus and have evolvedrelatively shorter tarsal claws. Two morphological groups of stygobitic species are evident, one including species lessdeviated from the ancestral (epigean) condition and another group comprising more modified species that typically havea larger size, a more or less pyriform head with a digitiform nasale, and a strongly reduced occipital foramen. Primarychaetotaxy of the species has remained a very conservative expression of the phenotype. Secondary chaetotaxy showsvariation among the species, the most obvious being the variable number of lamellae clypeales and the presence or absenceof secondary setae on the urogomphus. The phylogenetic relationships of Limbodessus are analyzed cladistically. Larvaeof this genus lack the primary pore ABc, which is a synapomorphy of the tribe Bidessini. As presently defined, Limbodessus is probably paraphyletic with respect to Allodessus Guignot, 1953.


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.


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